Mitigation Assessment Team Report

Hurricane Ike in Texas

and Louisiana

Building Performance Observations, Recommendations, 

and Technical Guidance

FEMA P-757 / April 2009 

FEMA
I

In response to Hurricane Ike, the Federal Emergency Management 

Agency (FEMA) deployed a Mitigation Assessment Team (MAT) 

to evaluate and assess damage from the hurricane and provide 

observations, conclusions, and recommendations on the performance of 

buildings and other structures impacted by wind and flood forces. 

The MAT included FEMA Headquarters and Regional Office engineers, 

representatives from other Federal agencies and academia, and experts 

from the design and construction industry. The conclusions and 

recommendations of this Report are 

intended to provide decisionmakers 

with information and technical 

guidance that can be used to reduce 

future hurricane damage.

In this photo taken by the MAT on September 19, 2008, a 

lone house in the Gilchrist neighborhood on the Bolivar 

Peninsula in Texas, survived Hurricane Ike.
MITIGATION ASSESSMENT TEAM REPORT

Hurricane Ike

in Texas and Louisiana

Building Performance Observations, 

Recommendations, and Technical Guidance

FEMA P-757 / April 2009

FEMA
MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

Executive Summary

Eric Letvin

Chapter 1

Vassiliki Koumoudis

Chris Jones

Larry Tanner

Wallace Wilson

Chapter 2

Larry Tanner 

Chris Jones

Dave Low

Wallace Wilson

Chapter 3

Chris Jones

Larry Tanner 

David Johnston

Dave Low

Mark Matulik

Tom Smith

Wallace Wilson

Chapter 4

Tom Smith 

David Conrad

Dave Low

Mark Matulik

Wallace Wilson

Chapter 5

Tom Smith

David Conrad

Chapter 6

All

Chapter 7 

All

Chapter 8 

Janice Olshesky

Team Leader

Paul Tertell, PE, FEMA HQ

Team Manager

Eric Letvin, PE, Esq., CFM, URS Group, Inc.

Team Members

Kent Baxter, FEMA Region 6

David L. Conrad, PE, PBS&J

Claudette Fetterman, FEMA HQ

Lois Forster, FEMA HQ

Philip Grankowski, International Code Council

David S. Johnston, Vinyl Siding Institute, Inc.

Christopher P. Jones, PE

Vassiliki Koumoudis, URS Group, Inc.

Emanuel Lain, Jr., MPA, FEMA LA TRO

Dave Low, PE, D.K. Low & Associates

CW Macomber, APA

Mark Matulik, CFM, MPA, Dewberry

Janice Olshesky, AIA, Olshesky Design Group LLC

Tim Reinhold, Institute for Business and 

Home Safety

Thomas L. Smith, AIA, RRC, TLSmith 

Consulting, Inc.

Larry J. Tanner, PE, MASCE, MAAWE, Wind 

Engineering Research Center, Texas Tech University

Charles Tobelman, FEMA LA TRO

Jonathan Westcott, PE, FEMA HQ

Brian Willsey, FEMA HQ

Wallace A. Wilson, PE, CFM, W.A. Wilson Consulting 

Services, LLC

Gary Zimmerer, PE, FEMA Region 6

Technical Editor: Susan Ide Patton, 

URS Group, Inc.

Publication Designer: Wanda Rizer, Consultant

Graphic Artist: Julie Liptak, 

Greenhorne & O’Mara, Inc.

Chapter Leaders and Authors

Team Members

Members of the Mitigation Assessment Team
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT i

Executive summary

Executive Summary

Hurricane Ike made landfall over Galveston, TX, on 

September 13, 2008 at 2:10 a.m. Central Daylight Time (CDT). 

Hurricane Ike was the ninth named storm during the 2008 

hurricane season and the most significant of the three that hit Texas 

in 2008. It was the seventh storm of the season to hit the United 

States mainland. At one point in time, the tropical-force winds 

spanned 600 miles across the Gulf of Mexico as the hurricane 

approached Texas. It is estimated that the storm surge generated by 

Hurricane Ike affected an area of approximately 310 miles along the 

Gulf of Mexico coastline.

Hurricane Ike is likely to be one of the costliest and most destructive hurricanes in U.S. history. 

Although Hurricane Ike was only a Category 2 hurricane when it made landfall near Galveston, 

TX, the large wind field of Hurricane Ike and the timing of when it struck, which included a 

period of increased tides, led to storm surge levels more typically associated with a Category 4 

Eric Letvin
ii MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

hurricane. This disparity is due to the fact that the Saffir-Simpson hurricane scale is based on 

typical storm characteristics, and Ike was atypical. Ike was a very large hurricane (tropical-stormforce and hurricane-force winds extended approximately 275 miles and 120 miles from the 

storm center, respectively). A proposed new storm classification system (Integrated Kinetic Energy classification) would place Ike as high as 5.2 on a scale of 1 to 6. 

The combination of surge and high waves was particularly destructive in areas along the Gulf of 

Mexico coast and parts of the Galveston Bay shoreline, particularly the Bolivar Peninsula, where 

preliminary numbers show that out of 5,900 buildings standing before Ike, approximately 3,600 

were destroyed, 400 sustained major damage (substantially damaged), 1,800 sustained some 

damage but were not substantially damaged, and 100 were undamaged or sustained only minimal damage. Flooding also damaged many homes and businesses in the City of Galveston; in 

communities surrounding Galveston Bay; in the Bridge City, TX, area; and in low-lying southwest Louisiana.

In January 2009, the Property Claim Services (PCS) of the Insurance Services Office revised 

its estimated insured losses to $10.655 billion from its original estimates of $8.1 billion. Based 

on the revised estimated insured losses, total losses are estimated at $21.3 billion, which would 

make Hurricane Ike one of the top five costliest U.S. hurricanes of all time. 

Mitigation Assessment Team (MAT)

For the past 25 years, the Federal Emergency Management Agency (FEMA) has studied the 

performance of buildings affected by disasters of national significance. Disasters of national 

significance provide opportunities for research on how hazards affect the built environment 

and also an opportunity to research the performance of current building codes and practices. 

This work is accomplished by the FEMA Mitigation Assessment Team (MAT). Often, recommendations from these findings have been adopted as statutes in model building codes, or 

just as importantly, as guidance for better and stronger construction practices. 

These broad-minded studies are driven by a core mission of FEMA’s Mitigation Directorate: to 

reduce damages from future disasters. They support an integral part of the Stafford Act, which 

is to reduce the loss of life and property that can occur from disasters. The ongoing study of the 

effects of these significant disasters and the documentation of findings will help in developing 

recommendations to enhance building performance. Improving building performance will reduce the vulnerability of population centers and critical infrastructure to natural hazards. This 

can be accomplished by exploiting the science and technology developed today, and imparting 

this knowledge to local communities through guidance and education. 

In response to a request for technical support from FEMA’s Joint Field Office in Austin, TX, 

and the Transitional Recovery Office in New Orleans, LA, FEMA’s Mitigation Directorate deployed a MAT to Texas and Louisiana in October 2008 to evaluate both building performance 

during Hurricane Ike and the adequacy of current building codes, other construction requirements, and building practices and materials. The MAT set out to investigate the following 

Executive summary
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT iii

issues and make appropriate conclusions and recommendations based on their observations 

of Hurricane Ike damage:

n Performance of new construction, especially foundation performance and performance 

against floodborne debris

n Performance of critical facilities (e.g., schools, hospitals, and first responder facilities)

n Performance of high-rise buildings in downtown Houston 

n Performance of hurricane-resistant homes on Bolivar Peninsula

n Performance of beach nourishment and reinforced dune projects in reducing flood 

damage

n Performance of FEMA-funded mitigation projects 

n Sustainable design considerations in hurricane-prone areas

Assessment Observations

In localized areas in Texas, the flood levels for Hurricane Ike exceeded the current design 

flood event (i.e., 100-year base flood event) illustrated on the FEMA Flood Insurance Rate Maps 

(FIRMs). The wind speeds from Hurricane Ike were less than the design speeds prescribed in 

American Society of Civil Engineers (ASCE) 7-05, Minimum Design Loads for Buildings and Other 

Structures.

Flood Damage

All the Texas and Louisiana communities visited by the MAT participate in the National Flood 

Insurance Program (NFIP) and have adopted floodplain management regulations that meet or 

exceed minimum NFIP requirements. Most of the communities have also adopted model building codes. However, unincorporated areas of Texas are not required to complete plan review, 

residential building design review, or building inspection by a State or county building official. 

One of the goals of the MAT was to investigate building failures in mapped flood zones. The 

MAT determined that some of the communities visited have adopted design and construction 

requirements more stringent than required by the NFIP for these zones, and that structural 

damage to newer buildings in these communities was generally less than in communities that 

have not adopted higher standards.

Compliance with NFIP design and construction provisions was lacking at some buildings and in 

some Louisiana communities. Problems were observed at residential and commercial buildings, 

and at critical facilities. Compliance issues seemed to be more frequent at older structures, but 

some problems were also noted at newer structures. 

A preliminary review of pre- and post-Ike aerial photographs suggests that 100 to 200 feet of 

dunes and vegetation were lost during Ike along much of the Gulf of Mexico shoreline. This 

loss occurred in areas with natural dunes and in areas where eroded dunes had been rebuilt 

Executive summary
iv MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

and reinforced with geotextile tubes. The MAT observed significant levels of erosion and scour 

around buildings situated near the Gulf. Erosion was widespread along the Gulf shoreline of 

Follets Island, Galveston Island, Bolivar Peninsula, and portions of southwest Louisiana. The 

MAT did not observe any significant erosion and scour along the bay shorelines, although there 

may have been some locations where such erosion and scour occurred. 

Overall, the damage observed by the MAT was consistent with typical wave damage patterns: 

damage to properly designed and constructed elevated homes was generally minor until the 

waves reached above the elevated floor system, at which point the damage increased dramatically with increasing water level and wave height. Performance of residential building foundations 

to coastal and near-coastal hazards depended primarily on the residence having adequate elevation, proper construction, and proper foundation selection. If any of these criteria were 

not satisfied, performance suffered. Several of the houses the MAT evaluated performed well, 

particularly where the foundations elevated the houses above flood levels, where the foundations were adequately constructed to resist the imposed forces, and where the foundations were 

founded deeply enough to resist scour and erosion.

Wind Damage

Though Hurricane Ike’s estimated wind speeds were less than the design wind speeds given in 

the current building code, the MAT observed widespread wind damage in the areas that were 

investigated. Although a very large number of buildings (including residential, commercial, 

and critical facilities) were damaged, much of the damage was light to moderate. Most of the 

wind damage was to building envelopes (primarily roof coverings, rooftop equipment, and wall 

coverings). Wind damage was most pronounced along the Bolivar Peninsula, the eastern portion of Galveston Island, and the areas bordering Galveston Bay. 

The MAT observed various types of building envelope damage at several buildings in downtown Houston. A few high-rise buildings in downtown Houston had extensive glazing damage. 

According to the current building code, the basic wind speed for downtown Houston is approximately 108 mph. The estimated maximum speed during Hurricane Ike was approximately 

94 mph. Several failure mechanisms were observed for building envelopes, specifically glazing 

damage.

The wind speeds in Louisiana were even less than those in Texas, and were also less than the 

design wind speeds given in the current building codes. Estimated wind speeds ranged from 

80 mph near the Texas/Louisiana border, to 50 mph in Vermilion Parish. East of Vermilion 

Parish, estimated wind speeds were less than 50 mph. Although wind damage did occur in 

Louisiana, it was not as significant as the damage in Texas. As is frequently observed during 

MAT investigations, damage to buildings and other structures is routinely produced by less 

than design wind speeds due to the following: lack of understanding and execution of basic 

wind-resistant design and construction practices; insufficient codes and standards at the time 

of construction; insufficient or lack of design guides and/or test methods at the time of construction; and improper or non-compliant building modifications or lack of maintenance by 

the property owners. 

Executive summary
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT v

Critical Facilities Damage

Several critical facilities, such as Emergency Operations Centers (EOCs), fire and police stations, hospitals, nursing homes, and schools were evaluated by the MAT in order to document 

building performance, as well as loss of function from Hurricane Ike. Critical facilities generally 

performed as expected. Those that were elevated higher and on stronger foundations sustained 

less damage. Those that were constructed in a manner similar to nearby, minimally compliant 

residential and commercial buildings sustained more damage.

Critical facilities with equipment and utilities in basements or at ground level tended to sustain 

flood damage to these support systems that either prohibited post-Ike resumption of operations, or delayed or reduced operational capabilities. At least one critical facility destroyed by 

Hurricane Rita and rebuilt prior to Ike appeared to have insufficient elevation, and will likely 

be flooded again. While Ike flooding did not enter the building, the below-floor utilities were 

damaged by Ike, and facility function was lost for a period of time. Critical facilities such as this 

should be elevated several feet above the base flood elevation (BFE) to reduce the likelihood of 

future flood damage. 

All of the critical facilities exposed to Hurricane Ike were subjected to wind speeds that were 

less than the design wind speeds given in the current building codes. Hence, while most of the 

critical facilities observed by the MAT experienced relatively little or no wind damage, the MAT 

observed issues indicating that if Hurricane Ike had delivered code design wind speeds, damage 

from poor wind performance would have been expected at many of these facilities. 

Recommendations

A few of the main recommendations based on observed building performance related to Hurricane Ike are provided below, as well as specific recommendations for improving wind- and 

flood-resistance of critical facilities.

Flood 

a. Until new flood maps are available and adopted, require the following freeboard 

above the Effective BFEs for new construction, substantial improvements, and repair 

of substantial damage: freeboard specified by the ASCE 24-05, Flood Resistant Design and 

Construction, plus 3 feet. Once new flood maps are available and adopted, require new 

construction, substantial improvements, and repair of substantial damage to be elevated 

to or above the freeboard elevation specified by ASCE 24-05.

b. Enforce ASCE 24-05’s Zone A design and construction standards in the area between the 

Effective Special Flood Hazard Area (SFHA) landward limit and a ground elevation equal 

to the adjacent Zone A Effective BFE plus freeboard.

c. Enforce ASCE 24-05’s Coastal A Zone design and construction requirements in areas 

presently mapped as Zone A on the Effective FIRM.

Executive summary
vi MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS AND LOUISIANA

d. FEMA should review its lowest floor elevation requirements for consistency with the 

requirements contained in the national consensus standard ASCE-24, Flood Resistant Design 

and Construction, and in light of the recommendations contained in the Evaluation of NFIP 

Building Standards (American Institutes for Research, 2006). Specifically, FEMA should 

consider requiring freeboard such that the entire floor system is at or above the BFE for all 

flood hazard zones. 

e. State and local governments should encourage siting away from eroding shorelines; 

employ coastal restoration, where justified, to mitigate erosion effects; and acquire erosiondamaged properties and prohibit reconstruction on those properties.

f. All new and replacement manufactured homes should be elevated to or above the BFE using 

wind- and flood-resistant foundations, such as those specified in the National Fire Protection 

Association 225-09, and installation of new manufactured homes should follow the guidance 

provided in FEMA 85, Manufactured Home Installation in Flood Hazard Areas (1985). (Note that 

FEMA 85 is currently under revision and is tentatively scheduled for release later in 2009.)

Figure ES-1 illustrates the recommendations outlined in bullets a, b, and c above.

Figure ES-1. Comparison of Effective BFEs and flood hazard zones (upper figure), with MAT-recommended 

freeboard and flood hazard zones (lower figure)

EXECUTIVE SUMMARY
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT vii

Wind 

a. An extensive amount of envelope wall covering, primarily vinyl siding and fiber cement 

siding, was damaged by Hurricane Ike. Municipalities with building code authorities, 

along with the Texas Department of Insurance (TDI) and their inspection program, 

should require that the installed products are on their approved and tested list and are 

installed in accordance with industry and manufacturer’s recommendations for highwind-zone installations.

b. Vinyl soffits and attic ventilation systems frequently failed, thereby allowing water 

infiltration into the homes, causing damage. The TDI and Building Inspection 

Program should ensure that vinyl soffits are installed in accordance with industry and 

manufacturer’s recommendations for high-wind-zone installations. 

c. Few impact-resistant laminated glass window units were observed by the MAT, with 

homeowners and builders opting to use shutters to provide windborne debris impact 

protection for glazed openings. TDI currently requires homes located in the Seaward 

Zone and the Inland (I) to be protected by impact-resistant glazing or shutters. The 

MAT recommends that opening protection by TDI include Inland (II [110 mph]) within 

1 mile of the coastal mean high water line where the basic wind speed is equal to or 

greater than 110 mph, which is consistent with ASCE 7-05 and International Residential 

Code (IRC) 2003 recommendations.

Critical Facilities 

a. New and replacement critical facilities should be sited outside the 500-year floodplain, 

where possible; where not possible, the critical facilities should be elevated higher 

than the residential and commercial building elevations called for in the flood 

recommendations. At a minimum, critical facilities should be elevated above the 500-

year flood level or the freeboard requirements of ASCE 24-05, whichever offers more 

protection to the facility.

b. Do not locate equipment and utilities in the basements or ground levels of critical 

facilities; locate these above the BFE-plus-freeboard elevation. If elevation of these 

components is not feasible for existing critical facilities in Zone A, evaluate dryfloodproofing of these areas to an elevation several feet above the BFE; if the building 

structure cannot accommodate flood loads associated with dry-floodproofing to this 

elevation, consider relocation of the critical facility or replacement with a new critical 

facility.

c. Perform a comprehensive vulnerability assessment of the Main Wind Force Resisting 

Systems and building envelope. As part of the evaluation process, prioritize the identified 

vulnerabilities. FEMA 543, Design Guide for Improving Critical Facility Safety from Flooding and 

High Winds: Providing Protection to People and Buildings (2007) and FEMA 577, Design Guide for 

Improving Hospital Safety in Earthquakes, Floods, and High Winds: Providing Protection to People 

and Buildings (2007) recommend such an evaluation, regardless of building age, for critical 

facilities located in hurricane-prone regions.

Executive summary
viii MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

d. Before a critical facility receives a grant from either the Hazard Mitigation Grant 

Program or the Pre-Disaster Mitigation Grant Program, the MAT recommends that a 

comprehensive vulnerability assessment be conducted. All significant wind vulnerabilities 

(including those related to interruption of municipal utilities) should be mitigated as 

part of the grant work, and for those that are not, the remaining residual risk should be 

recognized and documented.

ExEcuTIvE SuMMARy

viii MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT ix

TOC TABLE OF CONTENTS

Table of Contents 

Executive Summary....................................................................................................................i

Mitigation Assessment Team (MAT)............................................................................................... ii

Assessment Observations................................................................................................................ iii

Flood Damage ..................................................................................................................... iii

Wind Damage.......................................................................................................................iv

Critical Facilities Damage ..................................................................................................... v

Recommendations............................................................................................................................v

Flood .................................................................................................................................... v

Wind ..................................................................................................................................vii

Critical Facilities .................................................................................................................vii

1 Introduction........................................................................................................................ 1-1

1.1 Hurricane Ike – The Event............................................................................................... 1-2

1.1.1 Summary of Damage and Economic Loss ...........................................................1-5

1.1.2 Timeline and History of Hurricane Ike................................................................1-7

1.2 Coastal Flooding ............................................................................................................... 1-9

1.2.1 Shoreline Characteristics.......................................................................................1-9

1.2.2 Subsidence..............................................................................................................1-9

1.2.3 Hurricane Ike High Water Marks .......................................................................1-10
x MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

TABLE OF CONTENTS TOC

1.3 Wind Hazard Analysis and Discussion........................................................................... 1-12

1.3.1 H*Wind ................................................................................................................1-15

1.3.2 HAZUS-MH ..........................................................................................................1-16

1.4 Historic Hurricanes ........................................................................................................ 1-21

1.5 FEMA Mitigation Assessment Teams ............................................................................. 1-27

1.5.1 Purpose of the MAT.............................................................................................1-27

1.5.2 Team Composition...............................................................................................1-27

1.5.3 Methodology ........................................................................................................1-28

2 Floodplain Management Regulations, Building Codes, and Standards ..................... 2-1

2.1 Floodplain Management Regulations.............................................................................. 2-1

2.1.1 Flood Studies and Flood Maps .............................................................................2-2

2.1.1.1 Accuracy of Flood Insurance Studies and

Flood Insurance Rate Maps ...................................................................2-4

2.1.1.2 Implication of FIRMs on Rebuilding and Building Safety ...................2-6

2.1.1.3 Higher Regulatory Standards ................................................................2-6

2.2 Building Codes and Standards......................................................................................... 2-6

2.2.1 Flood Requirements ..............................................................................................2-8

2.2.1.1 Flood Requirements in the IBC and the IRC........................................2-8

2.2.1.2 Flood Requirements in ASCE 7-05.........................................................2-9

2.2.1.3 Flood Requirements in ASCE 24-05.....................................................2-10

2.2.1.4 Flood Requirements in Texas...............................................................2-11

2.2.1.5 Flood Requirements in Louisiana........................................................2-11

2.2.2 Wind Requirements.............................................................................................2-11

2.2.2.1 Wind Requirements in the IBC............................................................2-11

2.2.2.2 Wind Requirements in Texas ...............................................................2-11

2.2.2.3 Wind Requirements in Louisiana ........................................................2-17

2.2.3 HUD Manufactured Housing Design Standards ..............................................2-17

2.2.3.1 Manufactured Housing in Texas..........................................................2-19

2.2.3.2 Manufactured Housing in Louisiana ..................................................2-19

2.2.4 Galveston Residential Hurricane Resistance Study, 1990 .................................2-20

2.2.4.1 Ike MAT Observations of Houses in the 1990 Galveston Study .........2-21

2.2.4.2 MAT Summary of Findings Regarding the Galveston Study .............2-25
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT xi

TOC TABLE OF CONTENTS

2.3 Texas Windstorm Program ............................................................................................ 2-26

2.3.1 Texas Department of Insurance..........................................................................2-26

2.3.2 Basic Tenets of the Texas Windstorm Code .......................................................2-27

2.3.3 Texas Windstorm Program – Insights and Opinions.........................................2-29

2.4 Enhanced Code Construction ....................................................................................... 2-30

3 Performance of Residential Buildings (Flood and Wind), 

One- to Two-Family and Multi-Family............................................................................ 3-1

3.1 Structural Performance.................................................................................................... 3-1

3.1.1 Foundation Performance .....................................................................................3-2

3.1.1.1 Foundation Function 1: Elevate the Building .......................................3-5

3.1.1.2 Foundation Function 2: Resist Scour and Erosion .............................3-11

3.1.1.3 Foundation Function 3: Provide a Continuous Load Path 

to the Ground........................................................................................3-17

3.1.1.4 Foundation Function 4: Resist Flood Loads........................................3-21

3.1.2 Main Wind Force Resisting System .....................................................................3-27

3.1.2.1 High Winds ...........................................................................................3-27

3.1.2.2 Combination of Loads – MWFRS and C&C ........................................3-30

3.1.2.3 Load Paths.............................................................................................3-32

3.1.3 Elevation and Freeboard .....................................................................................3-39

3.1.4 Siting Effects on Structural Performance...........................................................3-40

3.2 Envelope Damage ........................................................................................................... 3-42

3.2.1 Roof Systems.........................................................................................................3-43

3.2.1.1 Asphalt Shingles....................................................................................3-44

3.2.1.2 Metal Panels ..........................................................................................3-50

3.2.1.3 Tile ........................................................................................................3-51

3.2.2 Non-Load-Bearing Walls and Wall Coverings ....................................................3-52

3.2.2.1 Brick Veneer ..........................................................................................3-55

3.2.2.2 Vinyl Siding............................................................................................3-57

3.2.2.3 Fiber Cement Siding.............................................................................3-64

3.2.2.4 Wood and Hardboard Siding ...............................................................3-68

3.2.3 Doors.....................................................................................................................3-69

3.2.4 Windows and Shutters .........................................................................................3-69

3.2.5 Soffit and Roof Ventilation..................................................................................3-75
xii MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

TABLE OF CONTENTS TOC

3.2.5.1 Soffits .....................................................................................................3-75

3.2.5.2 Ridge Vents ...........................................................................................3-77

3.2.5.3 Gable End Vents....................................................................................3-78

3.2.6 Exterior-Mounted Equipment.............................................................................3-79

3.3 Other Damage................................................................................................................. 3-81

3.3.1 Breakaway Walls ...................................................................................................3-81

3.3.2 Sheathing on the Underside of Elevated Buildings...........................................3-84

3.3.3 Parking Slabs and Grade Beams..........................................................................3-87

3.3.4 Mold and Contamination....................................................................................3-91

3.3.5 Other Issues and Problems..................................................................................3-91

3.4 Manufactured Housing................................................................................................... 3-92

3.4.1 Texas .....................................................................................................................3-93

3.4.2 Louisiana .............................................................................................................3-95

3.4.2.1 Cameron and Vermilion Parishes ........................................................3-95

3.4.2.2 Jefferson Parish .....................................................................................3-95

3.4.2.3 Lafourche Parish...................................................................................3-97

3.4.2.4 Manufactured Home Anchoring and Support Systems......................3-97

3.5 Mitigation Projects.......................................................................................................... 3-98

4 Performance of Critical Facilities ................................................................................... 4-1

4.1 Schools/Shelters............................................................................................................... 4-4

4.1.1 Crenshaw Elementary and Middle School (Port Bolivar, TX)............................4-4

4.1.2 South Cameron Parish High School (Grand Chenier, LA) ................................4-8

4.1.3 Johnson’s Bayou School, (Cameron,LA)..............................................................4-9

4.2 Hospitals/Health Centers .............................................................................................. 4-12

4.2.1 San Jacinto Methodist Hospital (Baytown, TX).................................................4-12

4.2.2 Winnie Community Hospital (Winnie, TX).......................................................4-17

4.2.3 University of Texas Medical Branch (Galveston, TX) .......................................4-20

4.2.4 South Cameron Parish Hospital, (Cameron,LA)...............................................4-27

4.2.5 Hackberry Rural Medical Clinic (Hackberry, LA).............................................4-31

4.2.6 Oceanview Transitional Care Center (Texas City, TX)......................................4-32

4.3 First Responder Facilities (Police/Fire/EOC).............................................................. 4-35
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT xiii

TOC TABLE OF CONTENTS

4.3.1 Houston Transtar – Regional EOC (Houston, TX) ..........................................4-35

4.3.2 Deer Park Police (Deer Park, TX) ......................................................................4-40

4.3.3 Port Neches Fire Station, (Port Neches,TX)......................................................4-42

4.3.4 High Island Fire Station (High Island, TX).......................................................4-45

4.3.5 Louisiana Fire Stations ........................................................................................4-46

 4.4 Other Government Buildings ........................................................................................ 4-50

4.4.1 U.S. Army Corps of Engineers Administration Building (Galveston, TX).......4-50

4.4.2 Federal Courthouse and Post Office (Galveston, TX) ......................................4-51

4.4.3 Tiki Island City Hall (Tiki Island, TX) ...............................................................4-54

4.4.4 Terrebonne Parish Criminal Justice Complex (Houma, LA) ...........................4-56

5 Performance of Buildings in Houston’s Central Business District ............................ 5-1

5.1 Areas Outside Clusters A and B ....................................................................................... 5-2

5.2 Cluster A – JP Morgan Chase Area .................................................................................. 5-6

5.2.1 Granite Veneer ....................................................................................................5-12

5.2.2 Roof Systems and Rooftop Equipment...............................................................5-12

5.2.3 Nearby Building Performance ...........................................................................5-13

5.3 Cluster B – Chevron Center Area .................................................................................. 5-16

5.3.1 Glazing..................................................................................................................5-17

5.3.2 Roof Systems and Rooftop Equipment ..............................................................5-20

5.3.3 Nearby Building Performance ............................................................................5-21

5.4 Vegetative Roofs.............................................................................................................. 5-25

6 Conclusions........................................................................................................................ 6-1

6.1 Residential......................................................................................................................... 6-2

6.1.1 Flood.......................................................................................................................6-2

6.1.2 Wind........................................................................................................................6-5

6.2 Critical Facilities................................................................................................................ 6-8

6.2.1 Flood.......................................................................................................................6-8

6.2.2 Wind........................................................................................................................6-9

6.3 Houston’s Central Business District............................................................................... 6-12
xiv MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS AND LOUISIANA

TABLE OF CONTENTS TOC

7 Recommendations ............................................................................................................ 7-1

7.1 Residential......................................................................................................................... 7-1

7.1.1 Flood.......................................................................................................................7-2

7.1.2 Wind........................................................................................................................7-6

7.2 Critical Facilities................................................................................................................ 7-7

7.2.1 Flood.......................................................................................................................7-8

7.2.2 Wind........................................................................................................................7-8

7.3 Further Studies and Standards Revisions...................................................................... 7-10

7.3.1 Flood.....................................................................................................................7-10

7.3.2 Wind......................................................................................................................7-10

7.3.3 Critical Facilities...................................................................................................7-13

7.4 Building Codes................................................................................................................ 7-17

8 Planning for a Sustainable Coast.................................................................................... 8-1

8.1 Geologic Hazards and Coastal Communities ................................................................. 8-2

8.1.1 Geologic Hazards That Threaten Coastal Communities.....................................8-2

8.1.1.1 Subsidence and Relative Sea Level Rise.................................................8-3

8.1.1.2 Shoreline Erosion ...................................................................................8-6

8.1.1.3 Dunes and Wetland Loss ........................................................................8-8

8.1.2 Discussion of Conflicts Between Coastal Communities 

and Geological Hazards.........................................................................................8-9

8.2 Existing Planning Resources and Programs.................................................................. 8-10

8.2.1 Texas ....................................................................................................................8-10

8.2.2 Louisiana .............................................................................................................8-11

8.2.3 Nationwide Initiatives ..........................................................................................8-12

8.3 Recommendations for Rebuilding After Ike................................................................. 8-15

8.3.1 Specific to Local Communities ...........................................................................8-15

8.3.2 General Recommendations – State Level ..........................................................8-17

8.3.3 General Recommendations – Federal Level ......................................................8-18
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT xv

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Appendices

Appendix A Acknowledgments

Appendix B References and FEMA Publication List

Appendix C Acronyms and Glossary

Appendix D FEMA Recovery Advisories

Appendix E High Water Marks

List of Figures

Chapter 1

Figure 1-1. Satellite image of Hurricane Ike as it moved toward Texas and Louisiana .......1-4

Figure 1-2. Areas affected by Hurricane Ike............................................................................1-5

Figure 1-3. Hurricane Ike storm track.....................................................................................1-8

Figure 1-4. Land subsidence in the Houston-Galveston area, 1906–2000 

(Harris-Galveston Subsidence District [HGSD], retrieved January 2009) ......1-10

Figure 1-5. FEMA’s surveyed locations of Hurricane Ike’s HWMs in Texas........................1-11

Figure 1-6. FEMA’s surveyed locations of Hurricane Ike’s HWMs in Louisiana ................1-12

Figure 1-7. Locations of monitoring stations and portable towers that reported data 

in Texas during Hurricane Ike............................................................................1-14

Figure 1-8. Wind swath contour plot based on H*Wind analysis; wind speeds given in 

mph with contours of the 1-minute sustained wind speed ...............................1-16

Figure 1-9. Wind swath contour plot (3-second gust at 10-meter elevation [33 feet 

above ground level]) at Texas and Louisiana based on HAZUS-MH wind 

field methodology ................................................................................................1-17

Figure 1-10. HAZUS-MH-estimated maximum peak gust wind speeds near radius of 

maximum winds...................................................................................................1-18

Figure 1-11. Map showing 1-minute sustained winds 3 hours after Galveston landfall 

with continued high back bay winds ..................................................................1-20

Figure 1-12. Roofing damage to north and west exposures produced by Hurricane Ike 

backside winds......................................................................................................1-21

Figure 1-13. Hurricane tracks of significant historic hurricanes in Texas and Louisiana ...1-22

Figure 1-14. Plaques near the Great Galveston Hurricane Memorial were destroyed 

by Ike.....................................................................................................................1-26
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Figure 1-15. The memorial capstone was moved off center by Ike........................................1-26

Figure 1-16. Flight plan for pre-MAT aerial reconnaissance..................................................1-29

Figure 1-17. Locations visited by the MAT in Texas and Louisiana.......................................1-30

Chapter 2

Figure 2-1. Floodplain management regulations and building design in communities 

with adopted building codes.................................................................................2-2

Figure 2-2. Relationship between the stillwater elevations, BFE, wave effects, and 

flood hazard zones.................................................................................................2-4

Figure 2-3. Elevation of residential structures to the BFE is required in Zone V .................2-4

Figure 2-4. Comparison of ASCE 7-05 and Ike gust wind speeds.........................................2-14

Figure 2-5. Galveston Island houses investigated for the 1990 report that were visited 

by the MAT in 2008 after Hurricane Ike ............................................................2-21

Figure 2-6. Indian Beach house, post-Ike (number 3289 in 1990 Galveston study)...........2-23

Figure 2-7. Point San Luis house (number 3083 in 1990 Galveston study) ........................2-24

Figure 2-8. Jamaica Beach house on the West Bay with “backside” wind damage 

(number 2480 in 1990 Galveston study) ............................................................2-24

Figure 2-9. First floor walls removed and floor slab undermined by flooding and waves 

at this Jamaica Beach house (number 2480 in 1990 Galveston study) .............2-25

Figure 2-10. Texas Windstorm Designated Catastrophe Areas ..............................................2-28

Chapter 3

Figure 3-1. Louisiana house sufficiently elevated on a foundation that withstood Ike 

flood loads..............................................................................................................3-3

Figure 3-2. A house on timber piles was pushed over by wind and flood loads and the 

load path failed at the connection between the floor beam and the piles ........3-3

Figure 3-3. Broken timber piles (Galveston Island, TX) ........................................................3-4

Figure 3-4. This concrete column failed due to lateral loads.................................................3-4

Figure 3-5. Typical bolted connection between wood columns and wood beams................3-5

Figure 3-6. Unlike the older and lower house on the right, the Zone V house on the 

left was elevated approximately 5 feet above the 16-foot National Geodetic 

Vertical Datum (NGVD) BFE and sustained no structural damage due to 

flooding (Crystal Beach, TX)................................................................................3-5

Figure 3-7. The landward displacement of shore-parallel floor joists indicates the 

onset of wave damage to an elevated floor system (Bolivar Peninsula, TX) ......3-6
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT xvii

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Figure 3-8. This elevated house (Zone V, BFE = 15 feet) suffered no significant 

damage due to flooding (Baytown, TX)...............................................................3-7

Figure 3-9. Adjacent houses south of Baytown, TX ................................................................3-7

Figure 3-10. The Ike flood level reached approximately 3 feet above the floor slab 

(1 foot above the 6-foot BFE) of this Zone A house (see inset), which was 

reported to have been similarly inundated during Hurricane Rita (Lake 

Charles, LA) ...........................................................................................................3-8

Figure 3-11. This house sustained significant structural damage due to storm surge and 

small waves above the 9-foot BFE in Zone A (Bridge City, TX) ..........................3-8

Figure 3-12. This house floated off its foundation due to insufficient elevation and 

inadequate connections between the foundation and the house (Golden 

Meadow, LA) ..........................................................................................................3-9

Figure 3-13. Looking toward the Gulf, past Zone V houses on tall concrete column 

foundations (with the lowest floor 10 feet above the 17-foot BFE) (Bolivar 

Peninsula, TX) .....................................................................................................3-10

Figure 3-14. Ground-level view of elevated houses with inset showing typical column 

damage where the timber deck broke away (Bolivar Peninsula, TX) ..............3-10

Figure 3-15. Concrete column showing cracking that was likely caused by extreme 

column bending stresses due to lateral loads on the elevated house and 

foundation (Bolivar Peninsula, TX) ...................................................................3-11

Figure 3-16. Pre- and post-Ike aerial photographs of the east end of Galveston Island, 

TX, illustrating some of the most significant loss of dunes and vegetation 

during Ike.............................................................................................................3-13

Figure 3-17. Exposed geotextile tubes formerly covered by sand and dune vegetation ......3-14

Figure 3-18. Foundation scour observed at Holly Beach, LA.................................................3-14

Figure 3-19. Foundation scour observed at Holly Beach, LA (Zone V, ABFE = 16 feet)......3-15

Figure 3-20. Foundation scour was reported to be 10 feet deep—note the bottoms of 

the piles on the right side of building that have been pushed toward the 

building (Bolivar Peninsula, TX; Zone V) .........................................................3-15

Figure 3-21. Failure of a timber pile foundation undermined by scour and erosion 

(Galveston Island, TX; Zone V) ..........................................................................3-16

Figure 3-22. Linear scour features tend to align with canals and roads as storm surge 

returns to the Gulf (Bolivar Peninsula, TX) ......................................................3-17

Figure 3-23. Example load path through a pile foundation (note: some building 

components are not shown)................................................................................3-18
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Figure 3-24. This Bridge City, TX, house sustained no structural damage, despite 

the fact that the owner reported that Ike flood levels rose above the 

lowest floor ...........................................................................................................3-18

Figure 3-25. A 5/8-inch diameter galvanized steel anchor bolt in red circle (with 

washer and nut, not visible in this photograph) provided connections 

between beam and column for the house shown in Figure 3-24 ......................3-19

Figure 3-26. Reinforcing steel extending from the top of a concrete column 

(building under construction) (Galveston Island, TX) ....................................3-19

Figure 3-27. Deterioration in the wood piling likely contributed to the foundation 

failure (Bolivar Peninsula, TX)...........................................................................3-20

Figure 3-28. Deterioration in wood piling (Galveston Island, TX) .......................................3-20

Figure 3-29. House resting (i.e., with no structural connection) on top of precast 

concrete piers, stacked CMUs, and shallow footing pads (New Iberia, LA) ....3-21

Figure 3-30. Idealized depth-damage relationship for an elevated building subject to 

waves ....................................................................................................................3-22

Figure 3-31. Pre- and post-Ike aerial photographs of the Crystal Beach area of Bolivar 

Peninsula, TX.......................................................................................................3-24

Figure 3-32. Seaward side of Zone V house struck by waves (Bolivar Peninsula, TX)..........3-25

Figure 3-33. Roofs, walls, and other parts of destroyed houses washed landward to and 

inland of this location, approximately 1⁄2 mile from the Gulf shoreline of 

Bolivar Peninsula, TX ..........................................................................................3-25

Figure 3-34. Broken piles beneath destroyed Gulf-front houses, Galveston Island, TX 

(west of the seawall).............................................................................................3-26

Figure 3-35. Damage to at-grade house in Zone V likely caused by wave and surge 

along the northern Galveston Bay shoreline in Baytown, TX...........................3-26

Figure 3-36. Likely wave and debris damage to townhouse building along the western 

Galveston Bay in Seabrook, TX...........................................................................3-27

Figure 3-37. ASCE wind speed map (ASCE 7-05) ...................................................................3-28

Figure 3-38. Code-defined MWFRS wind loads on an elevated residential structure...........3-29

Figure 3-39. Galveston, TX, West End Beach house with roof structure removed by 

Hurricane Ike.......................................................................................................3-29

Figure 3-40. This West Bay, Galveston Island, TX, apartment experienced gable-end 

wind damage as a result of sheathing failure and poor connection of the 

brick veneer to the stud walls (Hurricane Ike estimated wind speed in this 

area: 90 mph, Exposure B)..................................................................................3-30
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT xix

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Figure 3-41. The roof structure was poorly connected to this house in Grand Isle 

(Jefferson Parish, LA) and was blown off by 50-mph Ike winds 

(Exposure B) ........................................................................................................3-30

Figure 3-42. Areas of roof covering loss (red arrows) indicate zones of higher wind 

pressure on a roof................................................................................................3-31

Figure 3-43. Galveston, TX, West End Beach house with roof damage in high pressure 

zones (Hurricane Ike estimated wind speed in this area: 95 mph, 

Exposure C)..........................................................................................................3-31

Figure 3-44. Effect of wind on an enclosed building and a building with a wall opening 

producing a partially enclosed building by allowing internal pressurization 

of the structure.....................................................................................................3-32

Figure 3-45. Depiction of a building load path.......................................................................3-33

Figure 3-46. Load path around openings and connection to foundation pile.....................3-34

Figure 3-47. Collapse of a West Galveston Island, TX, house due to foundation failure.....3-34

Figure 3-48. Though much of the cladding and structural sheathing was destroyed by 

Ike’s surge, the MWFRS of this Bolivar Peninsula, TX, beach house 

remained intact and connected..........................................................................3-35

Figure 3-49. Strong concrete column-to-beam steel saddle connector .................................3-35

Figure 3-50. Strong interior wood column-to-beam connector with building shear 

wall connector ......................................................................................................3-36

Figure 3-51. Poor beam connection to corner column..........................................................3-36

Figure 3-52. Studs and sill plate connected in new house (sill bolts yellow arrows and 

clips red arrows) (Webster, TX) ..........................................................................3-37

Figure 3-53. Studs clipped to double top plate; rafter-to-top-plate connector has yet to 

be installed ...........................................................................................................3-37

Figure 3-54. Wall-to-roof strapping ..........................................................................................3-38

Figure 3-55. Toe-nailed connection of floor joists on band beam on house under 

construction (LaPorte, TX) ................................................................................3-38

Figure 3-56. Existing house shear wall connector incorrectly located (red arrow) 

(Sunset Crystal Beach, Bolivar Island, TX) ........................................................3-39

Figure 3-57. Post-Ike photograph of West Galveston Island, TX, illustrating increased 

severity of flood damage near the shoreline ......................................................3-40

Figure 3-58. Post-Ike photograph of Bolivar Peninsula, TX, illustrating increased 

severity of flood damage near the shoreline ......................................................3-40
xx MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

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Figure 3-59. A substantial amount of siding (the white lines scattered around the 

ground), along with roofing materials, blew off these West Galveston, 

TX, houses (Hurricane Ike estimated wind speed in this area: 90 mph).........3-42

Figure 3-60. Some of the roofs on these Jamaica Beach, TX, houses had no roof 

covering damage, while one had moderate damage (blue arrow) and 

one had extensive damage, including loss of underlayment (red arrow) 

(Hurricane Ike estimated wind speed in this area: 90 mph) ............................3-43

Figure 3-61. View of a shingle bundle wrapper at the Webster, TX, house shown in 

the inset ................................................................................................................3-45

Figure 3-62. Shingle damage at a house near the one shown in Figure 3-61 

(Webster, TX).......................................................................................................3-45

Figure 3-63. Loss of shingles along the eave in Bolivar Peninsula, TX (Hurricane Ike 

estimated wind speed in this area: 110 mph).....................................................3-46

Figure 3-64. Loss of shingles and underlayment in a corner area, and loss of shingles 

from the field of this roof in Bolivar Peninsula, TX (Hurricane Ike 

estimated wind speed in this area: 110 mph).....................................................3-46

Figure 3-65. Loss of hip shingles and portions of the underlayment in Bolivar Peninsula, 

TX (Hurricane Ike estimated wind speed in this area: 110 mph)....................3-47

Figure 3-66. Roof covering and roof structure damage at Fortified...for safer living®

houses in the Audubon Village area on Bolivar Peninsula, TX (Hurricane 

Ike estimated wind speed in this area: 110 mph) ..............................................3-48

Figure 3-67. This Fortified...for safer living® house had taped sheathing joints 

(red arrow) ...........................................................................................................3-49

Figure 3-68. This tape did not provide a watertight seal (Audubon Village, TX) ................3-49

Figure 3-69. These snap-lock seam panels were attached with fasteners through one side 

of the seam (Galveston Island, TX; Hurricane Ike estimated wind speed in 

this area: 110 mph) ..............................................................................................3-50

Figure 3-70. These architectural metal panels unlatched from the concealed clips 

(Galveston Island, TX; Hurricane Ike estimated wind speed in this area: 

110 mph). .............................................................................................................3-51

Figure 3-71. This tile roof on Galveston Island, TX, did not experience any wind 

damage (Hurricane Ike estimated wind speed in this area: 106 mph) ............3-52

Figure 3-72. This tile roof on Galveston Island, TX, experienced hip, eave, and field 

damage (Hurricane Ike estimated wind speed in this area: 106 mph) ............3-52

Figure 3-73. Loss of siding due to winds, Chauvin, LA (Terrebonne Parish; Hurricane 

Ike estimated wind speed in this area: 50 to 60 mph, Exposure B)..................3-53
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT xxi

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Figure 3-74. Loss of siding at Holly Beach, LA, home (Cameron Parish; Hurricane 

Ike estimated wind speed in this area 80 mph, Exposure C)............................3-53

Figure 3-75. Complete loss of thin gypsum sheathing and brick veneer from gable end 

(West Bay, Galveston Island, TX; Hurricane Ike estimated wind speed in 

this area: 90 mph, Exposure B)...........................................................................3-54

Figure 3-76. Loss of fiberboard sheathing and fiber cement siding from gable end wall 

of an apartment complex (West Bay, Galveston Island, TX; Hurricane Ike 

estimated wind speed in this area: 90 mph, Exposure B) .................................3-54

Figure 3-77. Collapsed brick veneer wall with brick ties at varied spacing, some of which 

were only partially imbedded or not embedded (West Bay, Galveston Island, 

TX; Hurricane Ike estimated wind speed in this area: 90 mph, Exposure B) ....3-55

Figure 3-78. Misalignment of the tie reduces the embedment and promotes veneer 

failure....................................................................................................................3-56

Figure 3-79. Proper installation and embedment of corrugated brick ties...........................3-56

Figure 3-80. Typical vinyl siding failure (Sea Isle, TX; Hurricane Ike estimated wind 

speed in this area: 95+ mph, Exposure C) .........................................................3-58

Figure 3-81. Improper installation led to extensive loss of siding up the house wall 

(Tiki Island, TX; Hurricane Ike estimated wind speed in this area: 88 

mph, Exposure B)................................................................................................3-59

Figure 3-82. Vinyl siding rated for high wind has a double-layer nail hem...........................3-60

Figure 3-83. Use of a generic starter strip contributed to loss of siding on this house 

(Tiki Island, TX; Hurricane Ike estimated wind speed in this area: 88 

mph, Exposure B)................................................................................................3-61

Figure 3-84. Loosely locked panel led to the siding failure of this Tiki Island, TX, house 

(Hurricane Ike estimated wind speed in this area: 90 mph, Exposure B) .......3-62

Figure 3-85. Use of utility trim under window to securely attach cut and notched 

siding section........................................................................................................3-63

Figure 3-86. Siding partially detached by wind as a result of improper placement of 

joint directly under window (Tiki Island, TX; Hurricane Ike estimated 

wind speed in this area: 88 mph)........................................................................3-63

Figure 3-87. Fiber cement plank siding, installed as a reside over the original plywood 

siding, was torn from this West Bay, Galveston Island, TX, house 

(Hurricane Ike estimated wind speed in this area: 100 mph, Exposure C).....3-64

Figure 3-88. Fiber cement lap siding was blown off this West Bay, Galveston Island, 

TX, house (Hurricane Ike estimated wind speed in this area: 100 mph, 

Exposure B)..........................................................................................................3-65
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Figure 3-89. Damaged fiber cement plank siding (Hurricane Ike estimated wind speed 

in this area: 93 mph, Exposure B) ......................................................................3-65

Figure 3-90. Standard and high wind zone installations ........................................................3-66

Figure 3-91. Shim placement (red arrow) allowed the lower edge (red circles) of siding 

to be exposed, resulting in loss of siding at several locations around this 

elevated structure on Bolivar Peninsula, TX (Hurricane Ike estimated 

wind speed in this area: 110 mph, Exposure C) ................................................3-67

Figure 3-92. Loss of fiber cement panels due to lower edge exposure (Bolivar 

Peninsula, TX; Hurricane Ike estimated wind speed in this area: 

110 mph, Exposure C).........................................................................................3-67

Figure 3-93. Clapboard-sided house with siding that performed well; damage resulted 

from failure of a non-breakaway wall (Tiki Island, TX; Hurricane Ike 

estimated wind speed in this area: 103 mph, Exposure C) ...............................3-68

Figure 3-94. Decayed plywood siding removed by wind pressures (Tiki Island, TX; 

Hurricane Ike estimated wind speed in this area: 103 mph, Exposure C).......3-68

Figure 3-95. Impact-resistant door and window glazing in new East Galveston, TX, 

house.....................................................................................................................3-70

Figure 3-96. Clear Lake, TX, house with plywood shutters installed on the accessible first 

floor and roll-down shutters installed on the less accessible second floor 

(Hurricane Ike estimated wind speed in this area: 90 mph, Exposure B) .......3-70

Figure 3-97. Tiki Island, TX, house with adjustable shutters (Hurricane Ike estimated 

wind speed in this area: 103 mph, Exposure C) ................................................3-71

Figure 3-98. Texas City, TX, house with corrugated clear plastic shutters (Hurricane 

Ike estimated wind speed in this area: 88 mph, Exposure B) ...........................3-71

Figure 3-99. Traditional wood swinging shutters on Tiki Island, TX (Hurricane Ike 

estimated wind speed in this area: 103 mph, Exposure B) ...............................3-72

Figure 3-100. Corrugated metal shutters on house in West Galveston, TX (Hurricane 

Ike estimated wind speed in this area: 95 mph, Exposure C)...........................3-72

Figure 3-101. Snapped-on vinyl canvas window covers (red arrows) in West Bay, 

Galveston Island, TX (Hurricane Ike estimated wind speed in this area: 

90 mph, Exposure B)...........................................................................................3-73

Figure 3-102. Common methods for plywood shutter attachment to wood-frame and 

masonry walls .......................................................................................................3-74

Figure 3-103. Plywood shutters installed into the wall cladding (red circles) in Clear 

Lake, TX (Hurricane Ike estimated wind speed in this area: 90 mph, 

Exposure B)..........................................................................................................3-74
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT xxiii

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Figure 3-104. Fiber cement soffit remained connected; soffit vent slots shown with red 

arrows (Tiki Island, TX; Hurricane Ike estimated wind speed in this area: 

88 mph, Exposure B)...........................................................................................3-76

Figure 3-105. Loss of aluminum fascia cover (red arrows) exposed ends of vinyl soffit 

(blue arrows) to direct entry of wind-driven rain (Tiki Island, TX; 

Hurricane Ike estimated wind speed in this area: 88 mph) ..............................3-77

Figure 3-106. Loss of fascia cover (red arrow) led to loss of soffit (blue arrow), exposing 

the attic to wind-driven rain (San Luis, TX; Hurricane Ike estimated wind 

speed in this area: 93 mph, Exposure C) ...........................................................3-77

Figure 3-107. The roof ridge vent (red arrows) on this Bolivar Peninsula, TX, home 

leaked, and it is presumed that the water was shed down the underside of 

the roof decking and/or structure, thereby producing ceiling damage 

along the wall of this second story room (Hurricane Ike estimated wind 

speed in this area: 110 mph, Exposure C) .........................................................3-78

Figure 3-108. Gable end vent (red arrow).................................................................................3-79

Figure 3-109. Shuttered gable end vent (red arrow)................................................................3-79

Figure 3-110. Gable end vent blew off this Galveston, TX, Back Bay apartment building 

(Hurricane Ike estimated wind speed in this area: 90 mph, Exposure B) .......3-79

Figure 3-111. Typical cantilevered condenser (Jamaica Beach, TX; Hurricane Ike 

estimated wind speed in this area: 80 mph, Exposure B) .................................3-80

Figure 3-112. Improperly secured condensing unit was knocked from its platform 

(Kahala Beach, TX; Hurricane Ike estimated wind speed in this area: 

80 mph, Exposure B)...........................................................................................3-80

Figure 3-113. Elevated condenser is tightly enclosed, making service access difficult 

(Bermuda Beach, TX; Hurricane Ike estimated wind speed in this area: 

95 mph, Exposure C)...........................................................................................3-81

Figure 3-114. Propagation of damage above lowest floor when breakaway walls broke 

free (Seabrook, TX).............................................................................................3-81

Figure 3-115. Attachment of utilities to breakaway wall may have prevented the wall 

from breaking away, thereby resulting in additional damage to the 

structure (Galveston Island, TX) ........................................................................3-82

Figure 3-116. This 11-foot high breakaway wall panel was pushed out by floodwaters 

trapped inside the enclosure (Galveston Island, TX) .......................................3-83

Figure 3-117. Louvered panels allowed Ike floodwaters to pass into and out of the belowBFE enclosure without damage to the panels....................................................3-83

Figure 3-118. Solid breakaway walls lost during Ike are being replaced with louvered 

panels (Tiki Island, TX) ......................................................................................3-84
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Figure 3-119. Plywood sheathing removed by storm surge (Jamaica Beach, TX, house 

on West Bay).........................................................................................................3-85

Figure 3-120. Fiber cement board sheathing (red arrow) was removed from the 

underside of this house, which was elevated approximately 12 feet 

above ground level (Bolivar Peninsula, TX) ......................................................3-85

Figure 3-121. Tiki Island house with vinyl soffit applied without sheathing removed by 

storm surge (netting was used to contain insulation in joist space).................3-86

Figure 3-122. Vinyl soffit covering over plywood sheathing partially removed 

(Tiki Island, West Galveston Bay; Estimated Hurricane Ike wind 

speed: 103 mph, Exposure C) .............................................................................3-86

Figure 3-123. Typical concrete parking slab beneath a pile-supported house 

(Bolivar Peninsula, TX).......................................................................................3-87

Figure 3-124. Undermining of concrete slab that settled but remained intact 

(Galveston Island, TX) ........................................................................................3-87

Figure 3-125. Pile-founded house with a slab thickened to create grade beams 

(Galveston Island, TX) ........................................................................................3-88

Figure 3-126. Slab failure probably contributed to foundation damage (West 

Galveston Island, TX) ..........................................................................................3-89

Figure 3-127. Slab undermining and settlement during Ike probably pulled piles 

downward (Holly Beach, LA)..............................................................................3-89

Figure 3-128. The weight of this slab, undermined due to scour and erosion, could 

have contributed to settlement and racking of this elevated house 

(Surfside Beach, TX)...........................................................................................3-90

Figure 3-129. Thin, unreinforced parking slab sections separated when undermined 

and collapsed in place, with no apparent adverse impact to the 

foundation (Galveston Island, TX).....................................................................3-90

Figure 3-130. Mildew and mold forming on wall sheathing following flooding 

(Golden Meadow, LA) .........................................................................................3-91

Figure 3-131. Floor joists and beams were notched to allow for plumbing 

(Sulphur, Calcasieu Parish, LA)..........................................................................3-92

Figure 3-132. Flood vent openings (red circles) that do not extend through the walls 

(Hackberry, Cameron Parish, LA)......................................................................3-92

Figure 3-133. Destroyed manufactured home (San Leon, TX)...............................................3-93

Figure 3-134. Scour depressions existed around the masonry piers, pads, and ground 

anchor stabilizer plates (San Leon, TX) ............................................................3-94

Figure 3-135. Manufactured home in Oak Island, TX .............................................................3-94
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Figure 3-136. Two manufactured homes in Cameron, LA.......................................................3-95

Figure 3-137. This elevated manufactured home in Grand Isle of Jefferson Parish, LA, 

had siding and roof damage, but did not move from its foundation...............3-96

Figure 3-138. The framing and anchoring system of the house shown in Figure 3-137 

(Estimated wind speed during Ike: less than 60 mph, 3-second gust) .............3-96

Figure 3-139. Zone A manufactured home in the Golden Meadows section of 

Lafourche Parish, LA, sustained 3 to 4 feet of flooding above the floor, 

but did not shift or float off of its foundation....................................................3-97

Figure 3-140. Prescriptive Flood-Resistant Foundation Design ...............................................3-98

Figure 3-141. Zone A house elevated with Increased Cost of Compliance funds on 

masonry piers (Iberia Parish, LA).......................................................................3-99

Figure 3-142. House elevated with Increased Cost of Compliance funds (Kemah, TX) 

(Hurricane Ike estimated wind speed in this area: 90 mph, Exposure B) .......3-99

Chapter 4

Figure 4-1. September 19, 2008, aerial view of Crenshaw Elementary and Middle 

School .....................................................................................................................4-4

Figure 4-2. General view of Crenshaw Elementary and Middle School ................................4-5

Figure 4-3. Wall of house washed underneath Crenshaw School during Ike (note 

shutters still attached to wall)................................................................................4-5

Figure 4-4. Location where the gutter blew off the gym roof; gutter bracket shown 

at inset.....................................................................................................................4-6

Figure 4-5. Wind blew off the hood, allowing rain to directly enter the building................4-7

Figure 4-6. Missing access panel allowed rain intrusion; ductwork could be easily 

flexed ......................................................................................................................4-7

Figure 4-7. Damage to South Cameron Parish School modular units ..................................4-8

Figure 4-8. High school gymnasium at South Cameron Parish School.................................4-9

Figure 4-9. Johnson’s Bayou School interior building damage .............................................4-9

Figure 4-10. Johnson’s Bayou School – damage to wall on front side of facility 

(soffit of driveway canopy was also damaged)....................................................4-10

Figure 4-11. Johnson’s Bayou School gymnasium interior damage.......................................4-10

Figure 4-12. Johnson’s Bayou School CMU wall collapse.......................................................4-11

Figure 4-13. Johnson’s Bayou School gymnasium...................................................................4-12

Figure 4-14. General view of San Jacinto Methodist Hospital................................................4-13
xxvi MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

TABLE OF CONTENTS TOC

Figure 4-15. Condenser with tie-down cables .........................................................................4-14

Figure 4-16. Detached LPS conductor.....................................................................................4-14

Figure 4-17. This satellite dish was held down with CMU only; inset shows all that 

remains from a similarly mounted dish after a strong hurricane .....................4-15

Figure 4-18. View of one of the mitigated roofs......................................................................4-17

Figure 4-19. A Winnie Community Hospital entry canopy (red oval) blew away .................4-18

Figure 4-20. Water entered the building where ductwork blew away ....................................4-18

Figure 4-21. Collapsed communications tower and blown-away access panels 

(red circle) ...........................................................................................................4-19

Figure 4-22. The emergency generator was housed within this shed; a portable 

generator (inset) was brought to the site after the emergency 

generator failed....................................................................................................4-20

Figure 4-23. High water mark (dashed blue line) shown from the outside of UTMB 

Building 1 .............................................................................................................4-21

Figure 4-24. Clean-up underway inside the basement of UTMB Building 1 ........................4-22

Figure 4-25. The Ike flood level in UTMB Building 56 pump room was approximately 

30 inches above the floor, and controls and equipment were damaged..........4-22

Figure 4-26. Replaced lower interior wall sections leading to UTMB Building 90...............4-23

Figure 4-27. A very high parapet kept the blown-off metal panels on the roof....................4-24

Figure 4-28. The roofs shown by the blue arrows were aggregate-surfaced BURs at the 

time Ike struck; the roof shown by the red arrow is a new roof replacing 

one that blew off ..................................................................................................4-25

Figure 4-29. A guyed stack that blew over ...............................................................................4-26

Figure 4-30. A relief air hood blew off the curb allowing rainwater to enter 

the building ..........................................................................................................4-26

Figure 4-31. Nine broken windows are shown in the red oval; the brown openings 

above the oval are louvers....................................................................................4-27

Figure 4-32. Hurricane Ike crested approximately 6 inches below the floor of the 

South Cameron Parish Hospital..........................................................................4-28

Figure 4-33. Conduits and pipes beneath South Cameron Parish Hospital .........................4-29

Figure 4-34. Damage to canopy over emergency room entrance driveway...........................4-29

Figure 4-35. Lack of proper fastening of rooftop equipment—a MAT member was 

able to easily lift this condenser unit off the curb..............................................4-30

Figure 4-36. Hackberry Rural Medical Clinic..........................................................................4-31
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT xxvii

TOC TABLE OF CONTENTS

Figure 4-37. Hackberry Rural Medical Clinic interior repairs in progress............................4-32

Figure 4-38. General view of Oceanview Transitional Care Center .......................................4-33

Figure 4-39. The fan shown in the inset blew off of this curb................................................4-34

Figure 4-40. Detached LPS conductor.....................................................................................4-35

Figure 4-41. Houston Transtar Regional EOC; significant permanent outward 

deformation occurred at the gutter shown in the inset ....................................4-36

Figure 4-42. The coping blew off because of inadequate attachment of the cleats..............4-37

Figure 4-43. Coping debris (red arrow); the membrane was gouged (blue arrow) 

by coping debris (an ink pen shows the scale)...................................................4-38

Figure 4-44. Coping debris (blue arrow) on a lower roof; note leaf debris near the 

scupper (red arrow).............................................................................................4-38

Figure 4-45. Guyed flue blew over (red arrow indicates one of the guys).............................4-39

Figure 4-46. The emergency generator is housed in the circled building; the coiling 

door (red arrow) and the louver (blue arrow) appeared to provide 

inadequate protection for the generator ...........................................................4-40

Figure 4-47. General view of Deer Park Police Station...........................................................4-41

Figure 4-48. The gutters are not attached to the gutter bracket; the inset shows a 

bracket at another building that provides a positive connection between 

the bracket and gutter .........................................................................................4-41

Figure 4-49. The emergency generator is inadequately protected from wind and 

windborne debris.................................................................................................4-42

Figure 4-50. General view of Port Neches Fire Station...........................................................4-43

Figure 4-51. View of a new motorized shutter; the toggle in the red circle allows the 

shutter to be manually raised..............................................................................4-43

Figure 4-52. The emergency generator is susceptible to windborne debris and damage 

caused by collapse of the masonry screen wall...................................................4-44

Figure 4-53. General view of High Island Fire Station............................................................4-45

Figure 4-54. The metal wall at the red oval area was pushed outward because of 

inadequate attachment of the wall angle to the slab .........................................4-46

Figure 4-55. The Bayou Grand Caillou Fire Station is elevated above the ABFE and 

sustained no damage ...........................................................................................4-47

Figure 4-56. Rear of Dularge Fire Station; note canal bank erosion sustained during 

Hurricane Ike.......................................................................................................4-48

Figure 4-57. 7th Ward Fire District No.1 Fire Station; wall repairs were in progress 

during MAT inspection........................................................................................4-48
xxviii MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

TABLE OF CONTENTS TOC

Figure 4-58. Condenser units were installed at Hackberry Fire Station after Ike and are 

vulnerable to future flooding..............................................................................4-49

Figure 4-59. Wind damage (red arrows) to Grand Isle Fire Station remaining from 

Hurricane Katrina................................................................................................4-49

Figure 4-60. General view of the USACE Administration Building in Galveston, TX..........4-50

Figure 4-61. The black material on top of the curb is a temporary covering to replace 

the sheet metal covering originally on the curb; shown in the red circle 

and inset ...............................................................................................................4-51

Figure 4-62. General view of Federal Courthouse and Post Office; some flashing 

damage occurred during Hurricane Ike (shown by red arrow) .......................4-52

Figure 4-63. All of the tile tails were hooked...........................................................................4-52

Figure 4-64. The access panel (red arrow) nearly blew away; the yellow arrows indicate 

supplementary anchor straps..............................................................................4-53

Figure 4-65. The emergency generator is housed in a separate wind- and windbornedebris-resistant building (red arrow)..................................................................4-54

Figure 4-66. One of the shutters at the Tiki Island City Hall is shown in the red oval; 

blue arrows indicate breakaway walls that performed successfully by 

breaking away .......................................................................................................4-54

Figure 4-67. The oval shows where ridge flashing blew away.................................................4-55

Figure 4-68. The electrical service entered through the wall rather than the roof; 

the blue arrows indicate missing breakaway walls..............................................4-56

Figure 4-69. Terrebonne Parish Criminal Justice Complex ...................................................4-57

Chapter 5

Figure 5-1. View of a portion of downtown Houston..............................................................5-3

Figure 5-2. Building with glazing damage; location shown by yellow square in inset ..........5-4

Figure 5-3. Random breakage of first floor glazing ................................................................5-5

Figure 5-4. Portions of the mechanical equipment screen wall blew away ...........................5-5

Figure 5-5. The wire mesh of this stucco wall was penetrated by windborne debris ............5-6

Figure 5-6. JP Morgan Chase Tower and JP Morgan Chase Center.......................................5-7

Figure 5-7. Most of the glazing in the yellow oval was broken (JP Morgan 

Chase Tower)..........................................................................................................5-8

Figure 5-8. Northwest façade glazing damage on JP Morgan Chase Center.........................5-9

Figure 5-9. View of repairs to an office damaged in the JP Morgan Chase Center ............5-10
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT xxix

TOC TABLE OF CONTENTS

Figure 5-10. Locations of possible debris sources that impacted the JP Morgan 

Tower and Center ................................................................................................5-11

Figure 5-11. The Tower is on the left and the Center is on the right....................................5-12

Figure 5-12. View of the JP Morgan Chase Tower roof...........................................................5-13

Figure 5-13. The main roof of the JP Morgan Chase Center (blue arrow) and 

several other roofs (indicated by yellow arrows) were blown off or 

damaged by debris...............................................................................................5-14

Figure 5-14. Glazing damage (yellow arrows) at two of the buildings shown in the 

white rectangle in Figure 5-13.............................................................................5-15

Figure 5-15. Several metal panels blew off of two façades of this building, along with 

a wall-mounted sign (yellow arrow) ....................................................................5-15

Figure 5-16. A substantial amount of glazing damage occurred to the façade of the 

Chevron Center, indicated by the yellow arrow .................................................5-16

Figure 5-17. Chevron Center glazing damage.........................................................................5-17

Figure 5-18. Broken glazing held in place with temporary film ............................................5-18

Figure 5-19. Portions of the roof system were blown off building B-1...................................5-19

Figure 5-20. The lightweight insulating concrete deck was gouged in many locations .......5-20

Figure 5-21. View of the damaged window washing track (green arrow) .............................5-21

Figure 5-22. Locations of nearby damaged buildings ............................................................5-21

Figure 5-23. View of buildings with glazing, roof and wall covering, and rooftop 

equipment damage ..............................................................................................5-22

Figure 5-24. Roof and wall covering, skylight, and roof-top equipment damage at 

building B-2 ..........................................................................................................5-23

Figure 5-25. Roof aggregate from building B-5 was the likely cause of the majority of 

the building B-4 glass damage.............................................................................5-23

Figure 5-26. View of the aggregate-surfaced roofs on building B-5 and broken glazing 

on building B-4 beyond .......................................................................................5-24

Figure 5-27. Stone veneer damage on backside of building B-5 (side facing B-4) ...............5-24

Figure 5-28. Roof covering damage on the main and penthouse roofs of building B-1 ......5-25

Figure 5-29. View of a vegetative roof in the downtown area.................................................5-26
xxx MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

TABLE OF CONTENTS TOC

Chapter 6

Figure 6-1. Two examples of elevation of equipment above grade on pile/column 

foundations, a good practice that ensured continuity of cell phone 

service on Bolivar Peninsula, TX ..........................................................................6-4

Figure 6-2. The upper windows on this Seabrook, TX, residence were not shuttered 

and were vulnerable to windborne damage .........................................................6-7

Figure 6-3. The tree shown by the red line nearly fell on the hospital’s emergency 

generator (red arrow)..........................................................................................6-10

Figure 6-4. Aggregate-surfaced BURs on two mid-rise buildings on the periphery of 

Houston’s central business district......................................................................6-13

Chapter 7

Figure 7-1. Comparison of Effective BFEs and flood hazard zones (upper figure), 

with MAT-recommended freeboard and flood hazard zones 

(lower figure) .........................................................................................................7-3

Figure 7-2. Several windows at this house on Bolivar Peninsula leaked and wetted 

the carpet..............................................................................................................7-12

Figure 7-3. The breakaway walls at this house were destroyed.............................................7-13

Chapter 8

Figure 8-1. Long-term trends in average annual sea level at selected tide gauges 

in the Gulf of Mexico ............................................................................................8-3

Figure 8-2. Relative sea level rise at Pier 21, Galveston...........................................................8-4

Figure 8-3. Broken geotextile tube at Beachside Drive, Galveston Island, TX .....................8-6

Figure 8-4. Broken geotextile tube at Beachside Drive, Galveston Island, TX .....................8-6

Figure 8-5. West end of the seawall at Galveston, TX .............................................................8-7

Figure 8-6. Beachtown, TX, under construction ..................................................................8-13

Figure 8-7. Beachtown, TX, under construction ..................................................................8-14
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT xxxi

TOC TABLE OF CONTENTS

List of Tables

Chapter 1

Table 1-1. Saffir-Simpson Hurricane Scale Wind Speeds and Pressures..............................1-3

Table 1-2. Notable Wind Speeds Recorded in Texas for Hurricane Ike............................1-14

Table 1-3. Estimated Maximum 3-Second Gust Wind Speeds for MAT 

Investigation Sites in Texas Based on Reporting Stations and 

HAZUS-MH Wind Model ....................................................................................1-19

Table 1-4. Damage Costs of Historic Hurricanes—Original and 2009 Dollars .................1-22

Chapter 2

Table 2-1. Codes in Effect at the Time of Hurricane Ike for Impacted Counties 

and Cities in Texas ...............................................................................................2-12

Table 2-2. Approximate Range of Basic Design Wind Speeds in the 

Coastal Counties Visited by the MAT (3-Second Gust, Exposure C, 

at 33 Feet Above Ground) ...................................................................................2-13

Table 2-3. Design Loads for a Typical Single-Family Residence in the 

City of Galveston, Galveston County, TX............................................................2-16

Table 2-4. Texas Counties covered by TWIA........................................................................2-26

Chapter 3

Table 3-1. Brick Veneer Tie Spacing ....................................................................................3-57

Chapter 4

Table 4-1. Critical Facilities Observed by the MAT ...............................................................4-2

Table 4-2. ASCE 24-05 Elevation Requirements for Critical Facilities .................................4-3

Table 4-3. Observations of Louisiana Fire Stations .............................................................4-47

Chapter 8

Table 8-1. Predicted Sea Level Increases ...............................................................................8-5

HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 1-1

INTROducTION 1

Introduction

On October 15, 2008, the Mitigation Division of the Department of 

Homeland Security’s (DHS) Federal Emergency Management Agency 

(FEMA) deployed a Mitigation Assessment Team (MAT) to the States 

of Texas and Louisiana to assess damage caused by the floodwaters 

and winds of Hurricane Ike. This report presents the MAT’s 

observations, conclusions, and recommendations in response to those 

field investigations.

This chapter provides an introduction, a discussion of the event, historical information, and 

background on the MAT process. Floodplain management regulations and building codes and 

standards that affect construction in Texas and Louisiana are discussed in Chapter 2. Chapter 3 

provides a basic assessment and characterization of the structural and envelope performance of 

residential buildings, including FEMA-funded mitigation projects in areas affected by Hurricane 

Ike. Chapter 4 presents damage to, and functional loss of, critical and essential facilities affected by Hurricane Ike. Chapter 5 presents damage to buildings in Houston’s Central Building 

1Introduction

Vassiliki Koumoudis

Chris Jones

Larry Tanner

Wallace Wilson
1-2 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

1 introduction

District. Chapters 6 and 7 present the MAT’s conclusions and recommendations, respectively, 

intended to help guide the reconstruction for hurricane-resistant communities in Texas and 

Louisiana, and other hurricane-prone regions susceptible to future hurricanes. Chapter 8 presents information on sustainable building practices, which are those practices that promote the 

longevity of buildings and the ecosystem. Although not generally part of a MAT report, this information is provided because sustainability issues are in the forefront of building responsibly. 

This information is intended to support the significant reconstruction effort that will follow 

Hurricane Ike. Over the past few decades, FEMA has provided guidance on hazard-resistance 

building practices. FEMA highly recommends that designers, architects, and planning officials 

in hurricane-prone areas refer to these publications. Relevant FEMA publications are provided 

in Appendix B. In addition, the following appendices are presented herein:

Appendix A: Acknowledgments

Appendix B: References and FEMA Publication List

Appendix C: Acronyms and Glossary of Terms

Appendix D: FEMA Recovery Advisories

n Attachment of Brick Veneer in High-Wind Regions (December, 2005; revised 2009)

n Design and Construction in Coastal A Zones (December, 2005; revised 2009)

n Designing for Flood Levels above the BFE (July, 2006; revised 2009)

n Enclosures and Breakaway Walls 

n Erosion, Scour, and Foundation Design 

n Minimizing Water Intrusion Through Roof Vents in High-Wind Regions 

n Metal Roof Systems in High-Wind Regions

n Siding Installation in High-Wind Regions 

Appendix E: FEMA High Water Marks for Hurricane Ike

1.1 Hurricane Ike – The Event

Hurricane Ike made landfall over Galveston, TX, on September 13, 2008, at 2:10 a.m. Central 

Daylight Time (CDT) as a large Category 2 hurricane. Hurricane Ike was the ninth named 

storm during the 2008 hurricane season and the seventh of the season’s storms to hit the U.S. 

mainland. It was the most significant of the three that hit Texas in 2008 and the second to hit 

Louisiana in a matter of weeks, with Gustav having hit southwestern Louisiana on September 

1, 2008. Hurricane Ike made landfall over Galveston, TX, on September 13, 2008, at 2:10 a.m. 

as a large Category 2 hurricane. Even though damages were still being tallied as of February 

2009, Hurricane Ike is likely to be one of the costliest and most destructive hurricanes in U.S. 

history; the total damage is estimated to be $21.3 billion, making it the fourth costliest hurricane in history behind Hurricanes Katrina (2005), Andrew (1992), and Wilma (2005) (National 

Hurricane Center [NHC], 2007). 
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 1-3

Introduction 1

Although Hurricane Ike was a Category 2 hurricane when it made landfall near Galveston, TX, 

the large wind field of Hurricane Ike led to storm surge levels more typically associated with a 

Category 4 hurricane. This disparity is due to the fact that the Saffir-Simpson hurricane scale 

(Table 1-1), the scale currently used to measure hurricane intensity, is based on typical storm 

characteristics, and Ike was atypical. Ike was a very large hurricane; tropical-storm-force and hurricane-force winds associated with Ike at the time of its landfall extended approximately 275 miles 

and 120 miles from the storm center, respectively. A proposed new storm classification system, 

called the Integrated Kinetic Energy classification (Powell and Reinhold, 2007), would place Ike’s 

storm Surge/Wave Destructive Potential (SDP) as high as a 5.2 (on a scale of 1 to 6) at mid-day on 

September 11, 2008 (refer to text box for additional information). Figure 1-1 provides a satellite 

image of Hurricane Ike that illustrates the size of the storm as it approached Galveston, TX. 

Table 1-1. Saffir-Simpson Hurricane Scale Wind Speeds and Pressures

Strength Sustained Wind 

Speed1

 (mph) Gust Wind Speed2

 (mph) Pressure (mb3)

Category 1 74-95 89-116 >980

Category 2 96-110 117-134 965-979

Category 3 111-130 135-159 945-964

Category 4 131-155 160-189 920-944

Category 5 >155 >189 <920

1

 1-minute sustained over open water 2 3-second gust over open water 3 mb = millibars

Integrated Kinetic Energy

The kinetic energy in a hurricane or any windstorm is proportional to the wind velocity squared. The Integrated 

Kinetic Energy (IKE) is calculated for a 1-meter deep layer of the storm centered at about a height of 10 meters and can be produced using any appropriate wind field that provides a map of sustained 1-minute winds. 

The IKE values reported are based on the H*Wind wind field produced by the Hurricane Research Division 

(HRD) of the National Oceanographic and Atmospheric Administration (NOAA) as an experimental product. 

The H*Wind wind field is used to produce contours of areas where the wind speeds are greater than tropical storm force, greater than hurricane force, and greater than very strong hurricane force winds ( >123 mph 

sustained winds). These estimates of IKE for areas experiencing wind speeds above certain thresholds are 

used to produce an SDP and a Wind Destructive Potential (WDP). The SDP is based on the total IKE for all 

areas where sustained wind speeds are greater than or equal to tropical storm force. The resulting IKE is expressed in terrajoules and is converted to a decimal value between 0 and 6.

What it is:

n A number between 0 and 6 that gives a relative measure of the wind field forcing over the ocean 

that can lead to high surge and wave damage

n The higher the number, the greater the potential for extensive along-shore inundation and damage from surge and waves

n Independent of bottom slope, coastline shape or properties at risk

What it is not:

n An accurate estimate of actual surge levels or damage since these depend on characteristics of 

the storm throughout its life cycle as it approaches the coast, and local effects including bottom 

slope, coastline shape, track of the storm, the roughness of the land surface, and property at risk.

Source: http://www.nhc.noaa.gov/aboutsshs.shtml
1-4 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

1 INTROducTION

Figure 1-1. Satellite image of Hurricane Ike as it moved toward Texas and Louisiana 

SOuRCE: http://www.srh.noaa.gov/hgx/projects/ike08.htm

The Saffir-Simpson Scale consists of five separate categories. The NHC reserves the term “major hurricane” for hurricanes that reach maximum 1-minute sustained surface winds of at least 

111 miles per hour (mph) over open water. Therefore, Category 3, 4, and 5 hurricanes are all 

considered major hurricanes.

Hurricane Ike’s significant storm surge caused damage to a widespread area across the upper 

Texas and southwestern Louisiana coast. Some of the hardest hit areas include the communities of Crystal Beach, Gilchrist, and High Island on the Bolivar Peninsula, TX (Figure 1-2). Parts 

of Galveston Island, TX, were also hit hard by the storm surge, although the seawall protected 

much of the City of Galveston from the direct impact by storm surge and wave action from the 

Gulf of Mexico. However, the seawall did not protect Galveston from flooding when water rose 

on the north side of the island from Galveston Bay. In Louisiana, storm surge caused flooding 

in Lake Charles in Calcasieu Parish, which is 30 miles inland. The storm surge also inundated areas in parts of Cameron, Vermilion, St. Mary, Terrebonne, Lafourche, Iberia, Jefferson, 

Plaquemines, St. Bernard, Orleans, St. Charles, St. John the Baptist, St. Tammany, Tangipahoa, 

Livingston, Ascension, and St. James Parishes. 

galveston
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 1-5

Introduction 1

Figure 1-2. Areas affected by Hurricane Ike

Hurricane Ike became extratropical as it moved inland over Arkansas. It continued through 

the Midwest and into the Ohio Valley, dumping between 6 and 8 inches of rain in parts of 

Indiana, Illinois, and Missouri (Minnesota Public Radio, 2008). Twenty-nine tornadoes were 

reported in association with Hurricane Ike. Luckily there were no deaths reported from the 

tornadoes. 

The Tropical Cyclone Report for Hurricane Ike published by the NHC on January 23, 2009 

(Berg, 2009) indicated that Hurricane Ike is directly responsible for 103 deaths across 

Hispaniola, Cuba, and parts of the U.S. Gulf Coast. The report also states that the latest 

official counts and media reports indicate that 20 people died in Texas, Louisiana, and 

Arkansas as a direct result of Hurricane Ike, and at least 64 indirect deaths were reported 

in Texas. According to the Laura Recovery Center,1

 33 people were still missing in Texas as 

of February 12, 2009.

1.1.1 Summary of Damage and Economic Loss 

The combination of surge and high waves were particularly destructive in areas along the Gulf 

of Mexico coast and parts of the Galveston Bay shoreline, particularly Bolivar Peninsula, TX. 

Preliminary numbers show that of the 5,900 buildings standing on Bolivar Peninsula before Ike, 

approximately 3,600 were destroyed, 400 sustained major damage (likely substantially damaged), 

1 NWS Houston/Galveston office, http://www.srh.noaa.gov/hgx/projects/ike08/wind_analysis.htm
1-6 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

1 introduction

1,800 sustained some damage but were not substantially damaged, and only 100 were undamaged 

or sustained only minimal damage (Halff Associates, 2008). Eastern areas of Trinity and Galveston 

Bays were inundated with floodwaters. In Bridge City, TX, 3,380 of the 3,400 residences in the city 

were inundated. Flooding also damaged many homes and businesses in the City of Galveston, on 

west Galveston Island and Follet’s Island, in communities surrounding Galveston Bay, and in lowlying southwest Louisiana. Final estimates on the total number of homes and businesses damaged 

in the affected areas were not available at the time of the publication of this report. 

Ports from Corpus Christi to Lake Charles were closed in advance of Ike. Damage to the Ports 

of Galveston and Houston, as well as debris in Galveston Bay and the Houston Ship Channel, 

kept those ports closed after the storm for several days, leaving almost 150 tankers, cargo vessels, 

and container ships waiting offshore. The U.S. Department of Energy said that 14 oil refineries 

were closed by the storm, as well as two Texas strategic petroleum reserve sites, causing rising 

gas prices and gas shortages across parts of the United States. In addition, the storm destroyed 

at least 10 offshore oil rigs and damaged several large pipelines. Before Ike reached the coast, 

a Cypriot freighter carrying petroleum coke, the 580-foot Antalina, lost propulsion about 90 

miles southeast of Galveston with its 22-man crew. The U.S. Coast Guard could not rescue the 

crew during the storm due to the hazardous weather conditions, but the ship rode out the storm 

without casualties.

In January 2009, the Property Claim Services (PCS) of the Insurance Services Office revised its 

estimated insured losses to $10.655 billion from its original estimates of $8.1 billion. Based on the 

revised estimated insured losses, total losses are estimated at $21.3 billion. PCS may increase its estimates again because it is considering including offshore properties in its catastrophe estimates, 

which it currently does not (Berg, 2009; Hays, 2009). 

The Louisiana Economic Development agency reported on September 18, 2008, that “conservative 

preliminary estimates suggest the total physical damage in Louisiana as a result of Gustav and Ike 

combined amounts to roughly $8 to $20 billion, including insured and uninsured losses.”2

 This 

amount includes only physical damage and does not include losses due to economic activity; as 

of the publication of this report, Louisiana Economic Development had not yet estimated that 

amount for Hurricane Ike alone. 

The U.S. Department of Energy estimated that 2.6 million customers lost power in Texas and 

Louisiana (NHC, 2009). Power outages were also experienced along Ike’s path as it moved 

northward through the United States. Ohio experienced the same level of power interruption 

as Texas and Louisiana combined, with almost 2.6 million people losing power. The Cincinnati, 

Columbus, and Dayton areas experienced significant wind damage from the remnants of 

Hurricane Ike. PCS estimates that the post-tropical remnants of Ike produced $2.3 billion in 

non-flooding related insured losses—this value equates to approximately $4.7 billion in damages. Insured losses in Ohio alone are estimated at $1.1 billion (Berg, 2009).

2 http://www.ledlouisiana.com/news--multimedia/news-releases/led-releases-hurricane-gustav-and-hurricane-ike-economic-impactassessment.aspx
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 1-7

Introduction 1

1.1.2 Timeline and History of Hurricane Ike

According to the NHC, Hurricane Ike originated as a well-defined tropical wave off the coast of 

West Africa on August 28, 2008. Tropical Storm Ike developed from a tropical depression west 

of the Cape Verde Islands on September 1, 2008. On September 3, 2008, the tropical storm had 

intensified and strengthened into a hurricane. Hurricane Ike continued its path west toward 

the Caribbean. On September 4, Hurricane Ike had strengthened to a Category 4 hurricane on 

the Saffir-Simpson scale, with maximum sustained winds of 145 mph.3

On September 7, Hurricane Ike made landfall over the Turks and Caicos Islands, with the 

eye of the storm coming directly over Grand Turk Island and over Great Inagua Island in the 

southeastern Bahamas. The hurricane continued on its westward path and made its first of two 

landfalls in Cuba as a strong Category 3 hurricane near Cabo Lucrecia. Hurricane Ike emerged 

over the ocean south of Cuba during September 8. The hurricane moved northwest through 

the night and made its second landfall in Cuba on Pinar del Rio on September 9. The storm entered the Gulf of Mexico as a Category 2 hurricane and continued its course toward Galveston 

Island, TX. Hurricane Ike produced tropical force winds over portions of the Florida Keys, but 

did not make landfall. The path of the hurricane is shown in Figure 1-3.

According to the National Weather Service,4

 the storm continued its track northwest making its 

way to the Texas coastline. As it made its way across the Gulf of Mexico, a few unique characteristics associated with this storm started to take place. The central pressure slowly fell from 968 

millibars (mb) upon entering the Gulf of Mexico to 944 mb by late on September 10. Although 

the decrease in central pressure generally indicates that the storm is intensifying, Hurricane Ike 

had unusually low sustained winds of 110 mph at that time. Another unique aspect was the large 

envelope of winds associated with Hurricane Ike. The hurricane continued to grow in diameter 

overnight. By 10 a.m. CDT on September 11, aircraft reconnaissance measured Ike’s tropical 

storm wind swath to be approximately 450 miles wide, with a hurricane force wind swath of 180 

miles. At that point, the National Oceanic and Atmospheric Administration (NOAA) issued a 

hurricane warning for the area between Morgan City, LA, and Baffin Bay, TX.

3 NWS Houston/Galveston office, http://www.srh.noaa.gov/hgx/projects/ike08/wind_analysis.htm

4 NWS Forecast Office, Lake Charles, LA, http://www.srh.noaa.gov/lch/ike/ikemain.php
1-8 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

1 introduction

On September 13 at 2:10 a.m. CDT, Hurricane Ike made landfall as a Category 2 hurricane on 

Galveston Island, TX, with reported sustained winds of 110 mph. Hurricane Ike made its final 

landfall at about 4:00 a.m. CDT near Baytown, TX.5

Hurricane Ike continued to move in a north and ultimately northeastern direction. By the afternoon of September 13, the hurricane was downgraded to a tropical storm by the NHC; it 

continued to weaken into a tropical depression before the center reached southwestern Arkansas 

later that evening. The storm continued its northeastern path, passing near St. Louis, MO, before it merged with a large cold front moving east across central United States. Hurricane Ike 

spawned a major wind event in the lower and middle Ohio Valley with strong wind gusts reported across parts of Kentucky, Indiana, Ohio, and Pennsylvania. Wind gusts of 75 mph were 

recorded in Columbus, OH.6

 According to American Society of Civil Engineers (ASCE) 7-05, 

Minimum Design Loads for Buildings and Other Structures, the design wind speed for the Ohio 

Valley is 90 mph (3-second gust).

Figure 1-3. Hurricane Ike storm track

5 NWS Houston/Galveston office, http://www.srh.noaa.gov/hgx/projects/ike08/wind_analysis.htm

6 Ibid.
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 1-9

Introduction 1

1.2 Coastal Flooding

The area affected by Hurricane Ike is a low-lying region susceptible to flooding by hurricane 

storm surge and freshwater flooding during heavy rain events (e.g., Tropical Storm Allison, 

2001). Flood Insurance Studies (FISs) and Flood Insurance Rate Maps (FIRMs) have been 

prepared for communities in the area since the 1970s and 1980s. A study is currently underway to update coastal flood hazard analysis and maps (the study was already in progress when 

Hurricane Ike struck).

1.2.1 Shoreline Characteristics

The region most directly affected by Hurricane Ike was from Brazoria County, TX, to Plaquemines 

Parish, LA, and adjacent inland areas. The eastern portion of the affected area, coastal Louisiana, 

is a low-lying chenier plain—intermittent sand ridges atop Mississippi River delta sediments, cut 

by tidal channels and embayments fringed with marsh. This plain extends west into eastern 

Texas, to the salt dome upon which the community of High Island sits. The shoreline from 

High Island, TX, to Freeport, TX, is composed of barrier islands of varying widths. The region 

landward of Galveston Island and Bolivar Peninsula is a large estuary known as Galveston Bay.

1.2.2 Subsidence

One factor that increases the vulnerability of the coastal region to hurricane storm surge is 

land subsidence—a lowering of the ground surface with respect to a fixed reference elevation. 

It can occur for a number of reasons, which vary geographically and over time (e.g., extraction 

of groundwater and hydrocarbon, tilt of underlying geologic strata, compaction of surface 

sediments, and interruption of natural delta sedimentation processes). Subsidence affects the 

entire region visited by the Ike MAT, from the Houston-Galveston region to coastal Louisiana. 

In portions of Texas, subsidence has been measured for over 100 years, and subsidence of 

several feet has been measured over a wide area; some land areas in Texas have dropped 10 

feet in elevation since 1906 (see Figure 1-4). Subsidence rates in coastal Louisiana are also high, 

reaching 0.8 foot/decade in places.7

 Subsidence also complicates flood hazard mapping and 

can render some flood hazard maps obsolete before they would otherwise need to be updated. 

7 Hurricane Katrina Flood Recovery (Louisiana), Questions and Answers about the Advisory Flood Elevations and the Katrina 

Recovery Maps. http://www.fema.gov/hazard/flood/recoverydata/katrina/katrina_la_faqs.shtm
1-10 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

1 introduction

1.2.3 Hurricane Ike High Water Marks

A total of 380 high water marks (HWMs) were 

surveyed by FEMA in Texas and Louisiana after 

Hurricane Ike. Figure 1-5 shows the locations 

of surveyed HWM in Texas, identifies each by 

type (stillwater, wave height, wave runup ), and 

provides the elevation (grouped, in feet North 

American Vertical Datum [NAVD]).8

 Figure 1-6 

provides HWM data for Louisiana. Appendix E 

of the report provides additional FEMA HWM 

maps and relevant data for Texas and Louisiana. 

Based on the preliminary HWM survey data, 

some areas of southeast Galveston Bay may have 

been affected by water levels over 20 feet NAVD. 

The stillwater level is estimated to have been in 

the range of 17 feet NAVD in areas of Chambers County, TX, and averaged about 15 feet NAVD 

near the Bolivar Peninsula, TX. 

Map contoured in 1-foot intervals

Figure 1-4. 

Land subsidence in the 

Houston-Galveston area, 

1906–2000 (HarrisGalveston Subsidence 

District [HGSD], retrieved 

January 2009) 

Source: http://www.

hgsubsidence.org/assets/

pdfdocuments/HGSD%20

Subsidence%20Map%201906-

2000.pdf

IKE FLOOD LEVELS

Although data reviewed by the MAT indicated that the area flooded by Ike exceeded 

the Effective Special Flood Hazard Area 

(SFHA), and Ike wave crest levels exceeded the Effective Base Flood Elevations 

(BFEs) by up to approximately 5 feet in east 

Texas and southwest Louisiana, Ike flooding should not be considered a rare event. 

A new flood study begun before Ike will 

likely show Ike flood levels to be below the 

new BFEs for much of the affected area.

8 For this report, the FEMA and Harris County Flood Control District HWM elevations are in NAVD of 1988, 2001 adjustment. 

The U.S. Geological Survey (USGS) HWM elevations are in NAVD of 1988.
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 1-11

Introduction 1

Figure 1-5. FEMA’s surveyed locations of Hurricane Ike’s HWMs in Texas

Based on preliminary results from the HWM surveys, southwestern areas of Cameron Parish, 

LA, may have been affected by water levels in the range of 12 feet. The stillwater level is estimated to have reached over 9 feet in the Lake Charles area of Calcasieu Parish. 
1-12 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

1 introduction

Figure 1-6. FEMA’s surveyed locations of Hurricane Ike’s HWMs in Louisiana 

1.3 Wind Hazard Analysis and Discussion

Hurricane Ike came ashore along Galveston Island and the Bolivar Peninsula early morning on 

September 13, 2008, as a Category 2 storm with 1-minute sustained winds of 110 mph, according 

to the NWS October 5, 2008, report.9

 The NHC Tropical Cyclone Report states that the landfall 

intensity of 110 mph was determined from three different sources: 1) flight level winds of 120 

mph using the standard 90 percent reduction to 

get the 10-meter, 1-minute average; 2) stepped 

Frequency Microwave Radiometer (SFMR) on 

the Hurricane Hunter Aircraft indicating 104 

mph; and 3) Weather Surveillance Radar 88 

Doppler System radar wind velocities from the 

NWS Houston/Galveston radar site that measured 130 mph at 6,500 feet above the ground 

Wind speed weather reporting stations 

include Automated Surface Observing 

Systems (ASOS), Coastal-Marine Automated Network (C-MAN), and portable 

meteorological towers deployed by universities or other agencies.

9 NWS Houston/Galveston office, http://www.srh.noaa.gov/hgx/projects/ike08/wind_analysis.htm
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 1-13

Introduction 1

(Berg, 2009). Although the NHC Report does not specify where this wind speed was measured, 

it is likely to have been close to a point over the Gulf southeast of High Island, TX. 

On land, reporting Automated Surface Observation System (ASOS) towers nearest the eye 

of the storm included Houston Hobby Airport and Bush Intercontinental Airport. Houston 

Hobby reported winds of 75 mph with gusts of 92 mph. Bush Intercontinental did not report 

hurricane-force winds despite the eye of Hurricane Ike passing reasonably close to the airport. 

Galveston Scholes Field stopped reporting prior to the passage of the hurricane’s eye due to 

storm surge. Other reporting stations included Coastal Marine (C-MAN) stations located at 

lighthouses, piers, and offshore navigation platforms. 

NOAA’s Office of Atmospheric Research (OAR) 

uses a 1-minute averaging time for reporting 

sustained winds. The maximum sustained wind 

referenced in National Hurricane Advisories 

for tropical storms and hurricanes is the highest 1-minute surface wind occurring within the 

circulation of the system. The ASOS stations average and report their wind data over a 2-minute 

period, but no conversion factor is required to 

change a 2-minute average wind into a 1-minute 

average wind, since they are virtually the same speed. The “surface” winds are those observed 

or estimated to occur at the standard meteorological height of 33 feet (10 meters) in an unobstructed exposure (i.e., not blocked by buildings or trees).10 Refer to the inset for the definition 

of wind exposure zones.

Normally, gusts are only a few seconds (3 to 5 seconds) of peak wind. Typically, in a hurricane 

environment, the value of the maximum 3-second gust over a 1-minute period is on the order 

of 1.3 times (or 30 percent higher than) the 1-minute sustained wind. ASCE 7-05 requires buildings to be designed using 3-second gust wind speeds (ASCE, 2005b).

In addition to aircraft, radar, and official monitoring stations, wind speeds were also obtained 

from portable land-based anemometers positioned along the storm’s path. Portable units included five 10-meter towers operated by the Florida Coastal Monitoring Program (FCMP) and 

18 towers (2.25-meter instrumented probes) provided by Texas Tech University (TTU). The 

highest land-based wind speed recorded by FCMP for Hurricane Ike was 116 mph, 3-second 

gust, recorded near Sea Breeze, TX, approximately 18 miles east of Anahuac, which is near the 

northeast corner of Galveston Bay. The highest speed recorded by TTU was also 116 mph, 3-second gust, recorded near Monroe City, which is approximately halfway between Anahuac and 

Sea Breeze, TX. The map in Figure 1-7 shows all of the stations and portable towers that reported data in Texas during Hurricane Ike. Table 1-2 provides a summary of the notable maximum 

recorded wind speeds. These data have been converted to 3-second gust wind speeds. Data has 

been adjusted for a 10-meter instrument elevation and Exposure C.

DEFINITION OF WIND

EXPOSURE ZONES

Exposure B. Urban, suburban, wooded 

areas

Exposure C. Open terrain, flat open 

country, grasslands, all water surfaces in 

hurricane-prone regions

10 NOAA, "H*Wind Swath Hurricane Ike," http://www.atmo.ttu.edu/TTUHRT/HWindSwath.png
1-14 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

1 introduction

Figure 1-7. Locations of monitoring stations and portable towers that reported data in Texas during Hurricane Ike

Table 1-2. Notable Wind Speeds Recorded in Texas for Hurricane Ike 

Data Collector Location (Station type) Wind Speed

Official Locations

FreePort (C-MAN) 93 mph

Galveston Island east end (C-MAN) 93 mph

Houston Hobby International Airport (ASOS) 98 mph

Houston George Bush International Airport 

(ASOS)

95 mph

Universities 

deploying portable 

meteorological 

towers at various 

locations

LaPorte (FCMP T4) 102 mph

Winnie (FCMP T5) 116 mph

Baytown (FCMP T2 & T3) 110 mph

Beaumont (TTU 108B) 103 mph

Anahuac (TTU 103A) 106 mph

Port Bolivar (TTU 110A) 94 mph

Monroe City (TTU 104B) 116 mph

Note: Wind speeds provided are 3-second peak gusts measured at 33 feet (10 meters), Exposure C.
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 1-15

Introduction 1

1.3.1 H*Wind 

As a result of both non-functioning wind-measuring instruments and a lack of instruments in 

the hurricane’s path (ASOS, C-MAN, and portable towers), few wind speed measurements reflect the actual strength of the storm. Thus, damage investigators and weather scientists estimate 

wind speeds based on a variety of methods, the most reliable being scientifically based wind models. The best known model in the public domain for estimating wind variations is H*Wind from 

NOAA’s Hurricane Research Division (HRD). Based on past experience of comparing modeled 

estimates with actual recorded wind speeds, the H*Wind model provides reasonably accurate 

estimates of maximum wind speeds over significant areas impacted by a storm. Contours of the 

1-minute sustained wind speeds from H*Wind analysis are shown in Figure 1-8. All wind speeds 

have been adjusted for a 10-meter instrument height and marine exposure over water or open 

terrain (Exposure C) over land.

HURRICANE IKE’S WIND SPEEDS RELATIVE TO DESIGN WIND SPEEDS

Texas. Though Hurricane Ike’s estimated wind speeds were less than design wind speeds given in the 

2006 International Building Code (IBC 2006)/ASCE 7-05, the MAT observed widespread wind damage 

in the areas that were investigated. Most of the wind damage was to building envelopes (primarily roof 

coverings, rooftop equipment, and wall coverings). A few high-rise buildings in downtown Houston had 

extensive glazing damage.

Although a very large number of buildings (including residential, commercial, and critical facilities) were 

damaged, the damage was light to moderate at many of the damaged buildings. Wind damage was 

most pronounced along the Bolivar Peninsula, the eastern portion of Galveston Island, and areas bordering Galveston Bay. 

Louisiana. Wind speeds in Louisiana were also less than the design wind speeds given in IBC 2006/

ASCE 7-05, and they were much less than those in Texas. Estimated wind speeds ranged from 80 mph 

near the Texas-Louisiana border to 50 mph in Vermilion Parish. East of Vermilion Parish, estimated wind 

speeds were less than 50 mph. Although wind damage did occur in Louisiana, it was not as significant 

as the damage in Texas.
1-16 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

1 introduction

Figure 1-8. 

Wind swath contour plot based on H*Wind analysis; wind speeds given in mph with contours of the 1-minute 

sustained wind speed 

Source: http://www.atmo.ttu.edu/TTUHRT/Ike.htm

1.3.2 HAZUS-MH

Another model for estimating wind speeds is FEMA’s HAZUS-MH (Hazards United States-MultiHazard) loss estimation model, which produces reasonable estimates of maximum speed and 

lateral distribution of wind. Figure 1-9 is a wind swath contour plot of maximum 3-second gust 

wind speeds in mph at a height of 33 feet (10 meters) above ground (over land wind speeds are 

representative of open terrain conditions; over water wind speeds are representative of marine 

conditions) produced by Hurricane Ike in Texas and Louisiana based on HAZUS-MH wind field 

methodology and modeled by Applied Research Associates (ARA, 2008). Figure 1-10 portrays 

the estimated maximum peak gust winds nearest the eye of Hurricane Ike, radius of maximum 

winds.
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 1-17

Introduction 1

The HAZUS-MH model for Hurricane Ike used weather data collected from the five FCMP portable towers, three C-MAN stations, and nine ASOS stations. The locations of these reporting 

stations are shown in Figures 1-9 and 1-10. The data are weighted and aggregated to develop 

a plot of the wind fields. The data collected from towers are influenced by ground exposure 

around the towers, which may differ from tower to tower. Given these conditions, the data from 

the towers are normalized for exposure and proximity to the storm path. Historically, these data 

have compared favorably with other modeled data.

Table 1-3 provides a summary of maximum recorded and modeled wind speeds for the sites investigated by the MAT. These data are 3-second gust wind speeds and have been standardized 

for 10-meter instrument heights and Exposure C. The conversion from Exposure B to Exposure 

C was made using an equivalent wind pressure calculation equation contained in ASCE 7-05. 

Figure 1-9. 

Wind swath contour plot (3-second gust at 10-meter elevation [33 feet above ground level]) at Texas and 

Louisiana based on HAZUS-MH wind field methodology. Anemometer locations used in model verification are 

indicated by the stars. 

Source: ARA, 2008
1-18 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

1 introduction

Figure 1-10. 

HAZUS-MH-estimated maximum peak gust wind speeds near radius of maximum winds. Stars indicate 

anemometer locations used in model verification. 

Source: ARA, 2008
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 1-19

Introduction 1

Table 1-3. 

Estimated Maximum 3-Second Gust Wind Speeds for MAT Investigation Sites in Texas Based on Reporting Stations 

and HAZUS-MH Wind Model

Data Source MAT Investigation Site

3-Second Gust Speed 

Estimate for Exposure 

C (Open Terrain)

3-Second Gust Speed* 

Estimate for Exposure 

B (Suburban Terrain)

Universities 

deploying 

portable 

meteorological 

towers at various 

locations

Anahuac 106 mph 90 mph

Baytown 100 mph 85 mph

Houston (City) 88 mph 75 mph

Jamaica Beach 90–95 mph* 75–80 mph*

LaPorte 102 mph 85 mph

Port Bolivar 94 mph 80 mph

Surfside 90 mph* 75 mph*

Winnie 110 mph 95 mph

HAZUS-MH 

modeled data

Audubon Village** 110 mph 95 mph

Beachtown 108 mph 93 mph

Crystal Beach** 110 mph 95 mph

Deer Park 95 mph 80 mph

Galveston (City) 100–105 mph 85–90 mph

High Island** 110 mph 95 mph

Houston Central 

Business District 90–94 mph 75–80 mph

Port Neches 90 mph 75 mph

Texas City 105 mph 90 mph

Tiki Island 103 mph 88 mph

* Calculated wind speeds, Exposure B—calculated from wind pressure conversions for components and cladding for buildings with 

a mean roof height of 33 feet (see ASCE 7-05, Table 6-3)

** Located on Bolivar Peninsula, TX

According to the HRD analysis, much of east Texas felt the brunt of hurricane force winds from 

the east side of the storm moving through Chambers and Jefferson Counties approximately 2 

hours after Ike made landfall. Maximum sustained winds on the east side of the storm were between 92 and 98 mph. Three hours later, at 5:30 a.m. CDT (1030 Universal Time Coordinated 

[UTC]), Hurricane Ike had continued to push north and begun to weaken. Even though the 

maximum sustained winds decreased to 80 to 85 mph, hurricane force winds still covered much 

of Galveston Bay and Chambers County through the southern part of Hurricane Ike (Figure 

1-11). Figure 1-11 also shows that Hurricane Ike still had hurricane force winds in the southern 

part of its core as shown by the red arrows, all of which contributed to the Galveston West Bay 

surge along the west end of the island and the wind damage noted on the north and western 

exposures of the building structures, as seen in Figure 1-12. Though the east side of a hurricane 

produces the highest wind speeds and surge levels, these graphics illustrate that damaging forces exist on the weaker west side of a storm.
1-20 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

1 INTROducTION

Hurricane Ike Tornadoes 

According to the NHC Tropical Cyclone Report for Hurricane Ike, a total of 29 tornadoes associated with Hurricane Ike were reported in Arkansas, Florida, Louisiana, and Texas (Berg, 

2009). Tornadoes spawned by hurricanes are normally in the lower range of intensity, EF0 or 

EF1 on the Enhanced Fujita (EF) Scale (65–110 mph); however, they frequently produce significant damage and even deaths. In this instance, no deaths were reported from the tornadoes.

Figure 1-11. 

Map showing 1-minute 

sustained winds 3 hours 

after Galveston landfall 

with continued high back 

bay winds 

SOuRCE: NWS, 2008

galveston Island
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 1-21

INTROducTION 1

1.4 Historic Hurricanes

The Texas and Louisiana coastlines have experienced many destructive hurricanes, with 

Hurricane Katrina being the most notable. The following section describes significant hurricanes that have damaged the Texas-Louisiana coastline beginning with the most recent, 

Hurricane Rita, and ending with the deadliest hurricane to affect the Galveston area, the Great 

Galveston Hurricane of 1900 (unless otherwise stated, information from NHC-NOAA).11 Figure 

1-13 shows the paths of the Great Galveston Hurricane and Hurricanes Audrey, Carla, Betsy, 

Celia, Allen, Alicia, Andrew, Katrina, and Rita. Table 1-4 shows the total estimated damages for 

each hurricane discussed in this section. 

Figure 1-12. 

Roofing damage to north 

and west exposures 

produced by Hurricane Ike 

backside winds

galveston Bay

gulf coast

11 http://www.nhc.noaa.gov/HAW2/english/history.shtml and Tropical Cyclone Reports for specific hurricanes found at http://www.

nhc.noaa.gov/pastall.shtml#tcr
1-22 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

1 introduction

Figure 1-13. Hurricane tracks of significant historic hurricanes in Texas and Louisiana 

Table 1-4. Damage Costs of Historic Hurricanes—Original and 2009 Dollars

Hurricane Year Original Cost of Damages

($ Million)

Cost of Damages in 2009 

Dollars ($ Million)

Rita1,2 2005 16,000 18,000

Katrina1,2 2005 125,000 139,000

Andrew1,2 1992 27,000 41,000

Alicia1,2 1983 3,000 6,000

Allen1 1980 600 1,500

Celia1 1970 453 2,220

Betsy1 1965 1,400 8,300

Carla1 1961 325 2,020

Audrey1 1957 147 970

Galveston3 1900 30 770

Notes:

1 Conversion factor used is from Consumer Price Index Conversion Factors to Convert to 2007 Dollars Table from Oregon State, 

http://oregonstate.edu/cla/polisci/faculty-research/sahr/cv2007rs.pdf

2 Estimated cost from NOAA paper, Billion Dollar U.S. Disasters, 1980–2008 (January 2009), 

http://www.ncdc.noaa.gov/img/reports/billion/billionz-2008.pdf

3 Conversion factor used is from Consumer Price Index Conversion Factors 1774 to estimated 2018 to Convert to 2006 Dollars Table 

from Oregon State, http://oregonstate.edu/cla/polisci/faculty-research/sahr/cv2006.pdf
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 1-23

Introduction 1

Hurricane Rita

Hurricane Rita struck the east side of the Texas-Louisiana border on September 24, 2005, as 

a Category 3 hurricane with 1-minute sustained winds of 115 mph. It produced storm surges 10 to15 feet above normal tide levels. The storm surge devastated coastal communities in 

southwestern Louisiana. Coastal areas of southeastern Louisiana were flooded by 4 to 7 feet of 

storm surge, including some areas that had already been impacted by the surge from Hurricane 

Katrina about 1 month earlier. Portions of the Florida Keys were inundated from the storm 

surge as well. Its winds, rain, and tornadoes caused fatalities and damages from eastern Texas to 

Alabama. A total of seven deaths and $16 billion worth of damage resulted from this storm. 

Hurricane Katrina

Hurricane Katrina, which struck the U.S. coast on August 25, 2005, now ranks as one of the 

most destructive hurricanes in U.S. history for cost (No. 1), deaths (No. 3), and intensity (No. 

3). Hurricane Katrina made its first U.S. landfall near Miami, FL, on August 25. The hurricane 

moved into the eastern Gulf of Mexico, and over the next 2 days it significantly strengthened to 

become a Category 5 hurricane. Hurricane Katrina made a second landfall on the LouisianaMississippi border as a Category 3 hurricane with 1-minute sustained winds of 127 mph at the 

Louisiana landfall and 120 mph 1-minute sustained winds at the Mississippi landfall. Storm surge 

flooding of 25 to 28 feet above normal tide level occurred along portions of the Mississippi coast 

and storm surge flooding of 10 to 20 feet above normal tide levels occurred along the southeastern Louisiana coast. This resulted in over 1,700 deaths and $125 billion in damages. It is ranked 

as the costliest hurricane in U.S. history. 

Hurricane Andrew

Hurricane Andrew struck Florida and Louisiana in August 1992. With total damage estimates at 

$27 billion, Hurricane Andrew is the second costliest hurricane in the United States. It is also 

ranked as one of the 10 most intense hurricanes in the United States, with a minimum pressure 

of 922 mb (27.23 inches) (NOAA, 2007). On August 24, Hurricane Andrew made landfall over 

south Florida as a Category 5 hurricane with peak gusts of 164 mph. The hurricane continued 

westward into the Gulf of Mexico where it made its second U.S. landfall on August 26 on the 

central Louisiana coast as a Category 3 hurricane. Andrew produced a storm tide of at least 8 

feet and inundated portions of the Louisiana coast. The total death toll was 65 people.

Hurricane Alicia

Hurricane Alicia, a Category 3 hurricane, struck southwest Galveston Island on August 17, 1983. 

Alicia had sustained winds over 96 mph with gusts of up to 125 mph along the coast. Hobby 

Airport at Houston reported 94 mph sustained winds with gusts to 107 mph. Hurricane Alicia 

is notable because it resulted in extensive glazing damage in high-rise buildings in downtown 

Houston (for further discussion of the glazing damage, see Chapter 5). Storm surges of 12.1 

feet were recorded at Morgan Point along Galveston Bay. It is believed that a total of 17 people 

lost their lives in this storm.
1-24 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

1 introduction

Hurricane Allen

Hurricane Allen is one of the top five most intense storms in history. The storm became a hurricane on August 3, 1980, about 120 miles east of Barbados as it made its way westward across 

the Atlantic. On August 7, 1980, the storm became the strongest hurricane recorded at that 

time, with sustained winds of 185 mph and higher gusts and a central pressure of 899 mb (26.55 

inches). Hurricane Allen made landfall as a Category 3 hurricane near Port Mansfield, TX, 

on August 10. The highest wind gust reported was from Port Mansfield, registering 138 mph. 

Storm surges reached 12 feet at Port Mansfield. A total of 34 tornadoes from this hurricane were 

known to have touched down across south Texas. About 300,000 people were evacuated. Seven 

died in Texas and 17 in Louisiana, with the majority of the deaths in Louisiana having occurred 

when a helicopter crashed trying to evacuate people from an offshore platform. Estimated damages in Texas and Louisiana were over $600 million at the time.

Hurricane Celia

On August 3, 1970, Hurricane Celia made landfall in Texas midway between Corpus Christi and 

Aransas Pass. Hurricane Celia had strong wind gusts estimated as high as 180 mph that far exceeded the hurricane sustained winds of 130 mph. The hurricane did not produce torrential 

rains and massive flooding over a large area as storms of this magnitude typically do. The heaviest storm rainfall was in the immediate Corpus Christi area, where 6 to 6.5 inches fell. Rains of 

3 to 4 inches or less accompanied the hurricane along its path across south Texas. The major 

cause of destruction from this storm was from the extreme winds. The final estimate of damage 

was placed at $453 million. Nine deaths and 466 injuries were a direct result of the storm.

Hurricane Betsy

Hurricane Betsy was a major hurricane of the 1965 hurricane season tracking through the 

Bahamas and Florida before making landfall on September 9, 1965, as a Category 3 hurricane at Grand Isle, LA. Hurricane Betsy brought 160 mph gusts and a 16-foot storm surge that 

flooded the entire island. Winds gusted to 125 mph in New Orleans and a 10-foot storm surge 

caused major flooding. Winds in most of southeast Louisiana reached 100 mph and, in areas as 

far inland as Monroe, winds exceeded 60 mph. Offshore oil rigs, public utilities, and commercial boats all suffered severe damage, resulting in approximately $1.4 billion in damage in 1965 

dollars. Seventy-six people lost their lives as a direct result of Hurricane Betsy, the first storm to 

cause $1 billion in damage. 

Hurricane Betsy caused surge effects in Lake Pontchartrain that caused a section of the levee to 

fail, resulting in flooding within New Orleans in the Ninth Ward and in the Chalmette area of 

St. Bernard Parish. In most low-lying areas of the city, floodwaters reached to the roofs of houses, 

resulting in drowning deaths of some of those who had sought refuge from the floodwaters in 

their attics. Water levels receded after approximately 10 days. It is estimated that approximately 

164,000 homes were flooded in Louisiana as a result of Hurricane Betsy. A new levee system, 

both higher and stronger than the former system, was constructed by the U.S. Army Corps of 

Engineers (USACE) and protected New Orleans from Hurricane Camille’s storm surge in 1969.
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 1-25

Introduction 1

Hurricane Carla

Hurricane Carla hit Texas on September 11, 1961. Carla ranks among the top 30 costliest and 

most intense hurricanes on record (NHC, 2007). A Category 5 hurricane at its peak, it was a 

Category 4 when it struck Port O’Connor and Port Lavaca, TX. The highest maximum sustained 

winds for Hurricane Carla were recorded at 175 mph, 1-minute sustained; the hurricane had 

storm surges of 22 feet. Approximately 250,000 people evacuated Texas. This hurricane also 

spawned 26 tornadoes through its path. Damages at the time were estimated at $325 million. 

Because of the large, effective evacuation, there were only 43 deaths due to this hurricane. 

Hurricane Audrey

Hurricane Audrey, a Category 4 hurricane, hit Louisiana and eastern Texas with winds of 145 

mph, 1-minute fastest-mile and storm surges of 6 feet on June 27, 1957. The highest surge was 

measured at 12.4 feet west of Cameron, LA. Two tornadoes in New Orleans and Ardaudville, LA, 

were reported. Audrey also spawned 23 tornadoes in Mississippi and Alabama. Its destruction 

continued through the Ohio Valley, Pennsylvania, New York, and Canada with severe rainfall, 

flooding, and winds of up to 80 mph, 1-minute fastest-mile. Audrey caused approximately 600 

casualties and $147 million of damage.

Great Galveston Hurricane

The deadliest hurricane in U.S. history was the Great Galveston Hurricane that occurred 

September 7 to 8 in the year 1900. This hurricane claimed approximately 8,000 lives. The population of Galveston in 1900 was approximately 37,000. This hurricane traveled the Caribbean as 

a tropical storm before making landfall across the southern United States where it hit Florida, 

Mississippi, Louisiana, and Texas. The hurricane then traveled through central United States 

and up through the Great Lakes making its way through Canada. The Great Galveston Hurricane 

was classified as a Category 4 at landfall, with sustained winds of 100 mph and gusts over 125 

mph. The minimum central pressure was 931 mb or 27.49 inches of mercury. The monument 

shown in Figure 1-14 commemorates the Great Galveston Hurricane; plaques around the statue 

were destroyed by Hurricane Ike.

The storm surge and high water level from the Great Galveston Hurricane washed out the four 

bridges linking Galveston to the mainland and downed telephone lines, cutting off the island 

from the mainland. The highest land elevation on Galveston Island in 1900 was 8.7 feet; the storm 

surge reached 15 feet. The damage to property was about $30 million. The horrific devastation of 

the hurricane propelled the people of Galveston to find a way to protect themselves against another disaster of this magnitude. Construction of a 17-foot-high seawall began in 1902 to protect 

3 miles of oceanfront and raise the city portion of the island by 8 feet. Sand was dredged from 

Galveston Bay to elevate the island. A memorial to the construction of seawall was erected after 

construction was completed; the monument was damaged by Hurricane Ike (Figure 1-15).
1-26 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

1 introduction

Future Hurricanes

Based on the history of hurricanes in this area, hurricanes of at least the same intensity can be 

expected to occur in the future. However, subsidence, shoreline retreat, and sea-level rise may 

increase the damaging effects of future hurricanes in some areas.

Figure 1-14. 

Plaques near the Great 

Galveston Hurricane 

Memorial were destroyed 

by Ike

Figure 1-15. 

The memorial capstone 

was moved off center by 

Ike
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 1-27

Introduction 1

1.5 FEMA Mitigation Assessment Teams

Along with responding to disasters and providing assistance to people and communities affected by disasters, FEMA conducts building performance studies after disasters in order to better 

understand how natural and manmade events affect the built environment. The intent of the 

studies is to reduce the number of lives lost to these events and minimize the economic impact 

on the communities where these events occur. Also, lessons learned are applied to the rebuilding 

effort after disasters to enhance the disaster-resistance of new construction and building repairs 

using recommendations provided in the MAT report. The MAT studies the adequacy of current 

building codes, other construction requirements, and building practices and materials.

Following a Presidentially declared disaster, FEMA determines the potential need to deploy one 

or more MATs to observe and assess damage to buildings and structures, as caused by wind, rain, 

and flooding associated with the storm. FEMA bases this need on estimates from preliminary 

information of the potential type and severity of damage in the affected area(s) and the magnitude of the expected hazards. These teams are deployed only when FEMA believes the findings 

and recommendations derived from field observations will provide design and construction 

guidance that will not only improve the disaster resistance of the built environment in the impacted State or region, but will also be of national significance to all disaster-prone regions. 

1.5.1 Purpose of the MAT

In response to a request for technical support from FEMA’s Joint Field Office in Austin, TX, and 

the Transitional Recovery Office in New Orleans, FEMA’s Mitigation Division deployed a MAT 

to Texas and Louisiana on October 15, 2008, to evaluate both building performance during 

Hurricane Ike and the adequacy of current building codes, other construction requirements, 

and building practices and materials. One of the major objectives of the MAT is to provide recommendations that can help reduce future damage from natural disasters.

The flood levels for Hurricane Ike exceeded the current design flood event (i.e., 100-year base 

flood event) in localized areas in Texas and Louisiana, as illustrated on the FEMA FIRMs. The 

wind speeds from Hurricane Ike were less than the design speeds prescribed in IBC 2006/ASCE 

7-05.

FEMA was interested in the performance of new construction, hurricane-resistant homes on the 

Bolivar Peninsula, and residential structures and critical facilities that received FEMA mitigation funding, as well as houses in communities requiring freeboard. Of particular interest was 

the issue of sustainability and how it relates to rebuilding efforts. The MAT was also tasked with 

evaluating the performance of approximately 40 buildings on Galveston Island that were previously evaluated by TTU.

1.5.2 Team Composition

The MAT included FEMA Headquarters and Regional Office engineers and experts, technical consultants, and construction industry experts. Team members from FEMA’s database of 
1-28 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

1 introduction

national experts included structural engineers, architects, wind engineers, civil engineers, 

and coastal scientists. In addition, there were representatives from the American Institute of 

Architects (AIA), the American Planning Association (APA), the Institute for Business and 

Home Safety (IBHS), the International Code Council (ICC), the National Association of Home 

Builders (NAHB), the Texas Association of Builders, the Vinyl Siding Institute (VSI), and TTU. 

In response to the unique situation presented by the substantial flooding in both Texas and 

Louisiana, a separate flood team was deployed for each State. 

The MAT received invaluable support from independent Texas and Louisiana home builders 

and guides that assisted the MAT. They accompanied the MAT through many of the affected areas, providing valuable insights regarding local construction practices. 

1.5.3 Methodology

Five days after Hurricane Ike struck the Texas/Louisiana Gulf Coasts (September 18 and 19), 

preliminary field investigations were performed by MAT members to assess overall building 

damage in limited areas of Texas. This investigation was tasked to observe and record perishable 

damage data and to locate damaged areas requiring further investigation. This survey included 

ground surveillance and aerial reconnaissance in the areas shown in Figure 1-16. The initial leg 

of the aerial reconnaissance focused on downtown Houston to look at window breakage in highrise buildings (such as the JP Morgan Chase Building) and the Galleria area to observe roof and 

glazing damage. From the downtown area, the reconnaissance proceeded to the coastal areas 

starting at Surfside Beach and continuing along the beach side of Galveston Island, across the 

channel and up the Bolivar Peninsula to High Island. The return leg included observation of 

the bayside damage of the Bolivar Peninsula, San Leon, Seabrook, and LaPorte. 
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 1-29

Introduction 1

Figure 1-16. Flight plan for pre-MAT aerial reconnaissance

Based on findings from the preliminary field investigation, FEMA decided to deploy the full 

MAT. Consequently, the MAT was deployed on October 15 for 1 week. The MAT was separated into three teams: a flood team for Texas, a wind team for Texas, and a flood team for 

Louisiana. 

The Texas MATs conducted extensive ground observations from October 16 through October 

21, 2008, in the following locations:

n Brazoria County: Surfside Beach

n Galveston County: Galveston Island, Bolivar Peninsula, and cities and towns along 

Galveston Bay on the mainland

n Harris County, including downtown Houston

n Chambers County

n Orange County
1-30 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

1 introduction

The Louisiana MAT conducted observations from October 15 through October 20, 2008, in the 

following parishes:

n Calcasieu

n Cameron

n Vermilion

n Iberia

n St. Mary’s

n Terrebonne

n Lafourche

n Jefferson 

Figure 1-17 provides details on the locations visited by the MAT in Texas and Louisiana. 

Figure 1-17. Locations visited by the MAT in Texas and Louisiana

Damage was observed to single- and multi-family buildings, manufactured housing, commercial 

buildings, and historic buildings. In addition, critical facilities, such as Emergency Operations 

Centers (EOCs), fire and police stations, hospitals, nursing homes, and schools were also evaluated in order to document building performance as well as loss of function from Hurricane Ike. 

Documentation of observations is presented in this report. Photographs and figures are included to illustrate building performance in the wind field and surge areas produced by Hurricane 

Ike. The conclusions and recommendations of the MAT’s findings will assist in minimizing damages from future hurricanes.
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 2-1

FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS 2

Floodplain Management 

Regulations, Building Codes, 

and Standards

Floodplain management regulations, building codes, and standards 

are adopted and enforced to regulate construction in at-risk areas. 

The floodplain management regulations applicable to the areas affected by Hurricane Ike are 

discussed in Section 2.1. Section 2.2 presents the building codes and standards specific to floods 

and wind used to regulate construction. Section 2.3 discusses the Texas Windstorm Program. 

Section 2.4 discusses enhanced code construction.

2.1 Floodplain Management Regulations

National Flood Insurance Program regulations form the basis of a community’s efforts to guide 

development in flood hazard areas. These regulations are incorporated into a community’s 

floodplain management ordinance, and have been integrated into national consensus standards 

2Floodplain Management 

Larry Tanner 

Chris Jones

Dave Low

Wallace Wilson
2-2 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

2 FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS

(ASCE 7 and ASCE 24) and model building codes that are adopted by communities. Figure 2-1 

illustrates the process by which NFIP regulations flow to an individual building. 

All the Texas and Louisiana communities visited by the MAT participate in the NFIP, have adopted floodplain management regulations that meet or exceed minimum NFIP requirements, 

and are governed by minimum building and performance standards or a model building code 

(see Section 2.2), so the process outlined in Figure 2-1 applies. These communities have two 

avenues for enforcing flood-resistant design and construction practices: the floodplain management ordinance and the minimum standards/building code. To address the flood coordination 

issues between the floodplain management ordinance and the building standards/code, communities may wish to refer to FEMA 9-0372, Reducing Flood Losses Through the International 

Codes: Meeting the Requirements of the National Flood Insurance Program (December 2008).

2.1.1 Flood Studies and Flood Maps 

FEMA and its mapping partners conduct FISs to create and update FIRMs. FIRMs identify areas 

of varying flood hazard as flood zones. Zones A and V comprise the area known as the SFHA. Locations designated as SFHAs have a 1-percent annual chance, or greater, of being inundated by 

flooding in any given year. The 1-percent annual chance flood is also referred to as the “base flood” 

or the “100-year flood.” Areas that flood less frequently than the SFHA are also shown on FIRMs. 

The Shaded Zone X (old map designation Zone B) indicates the area that has between a 1-percent 

and 0.2-percent annual chance of flooding (this is commonly described as the area subject to flooding between the 100-year and 500-year floods). The Unshaded Zone X (old map designation Zone 

C) indicates the area that has less than a 0.2-percent annual chance of flooding.

Figure 2-1. Floodplain management regulations and building design in communities with adopted building codes
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 2-3

FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS 2

FIRMs show BFEs in Zone V, and Advisory Base 

Flood Elevations (ABFEs) represent the minimum 

elevation to which the lowest floors of buildings 

must be elevated. When a community joins the 

NFIP and adopts its FIRM, the community is also 

adopting minimum building floor elevations and 

other floodplain standards required by the NFIP. 

Figure 2-2 shows the relationship between stillwater 

elevations, BFEs, and wave effects.

The FIRM zone designation and the BFE are critical factors in determining which requirements 

apply to a building and, as a result, how it is built. 

For example, the NFIP minimum requirements 

for buildings built in Zone V (Coastal High Hazard Areas) are: 

1. Building must be elevated on pile, post, 

pier, or column foundations (refer to 

Section 3.1.1.1)

2. Building must be adequately anchored to 

the foundation (refer to Section 3.1.1.3)

3. Building must have the bottom of the 

lowest horizontal structural member 

supporting the lowest floor at or above 

the BFE (Figure 2-3)

4. Building design and method of 

construction must be certified by a 

design professional

5. The area below the BFE must be either 

free of obstructions or have breakaway 

construction in the form of nonsupporting breakaway walls, lightweight 

open lattice or louvers, or insect 

screening (refer to Section 3.3.1)

In Zone A, the NFIP only requires that the top of 

the lowest floor of a building be at or above the 

BFE. There are no standards for foundations other than the general performance standard that 

the building be anchored to resist floatation, collapse, and lateral movement; any type of foundation that meets this performance standard is 

permitted by the NFIP. Also, in Zone A, the NFIP permits non-residential buildings to be floodproofed, with their walls made substantially impermeable to the passage of floodwater. 

DESCRIPTION OF FLOOD 

ZONES 

Zone V. The portion of the SFHA that extends from offshore to the inland limit of a 

primary frontal dune along an open coast, 

and any other area subject to high-velocity 

wave action (3 feet and higher) from storms 

or seismic sources. The FIRMs use Zones 

VE and V1-30 to designate these Coastal 

High Hazard Areas. 

Zone A.The portion of the SFHA not mapped 

as Zone V. Although FIRMs depict Zone A 

in both riverine and coastal floodplains (as 

Zones A, AE, A1-30, and AO), the flood hazards and flood forces acting on buildings in 

those different floodplains can be quite different. In coastal areas, Zone A is subject to 

wave heights less than 3 feet and wave runup depths less than 3 feet. 

Coastal A Zone. The Coastal A Zone is an 

area within Zone A that is shown as an advisory layer on newer digital FIRMs (DFIRMs) 

using the Limit of Moderate Wave Action 

(LiMWA) line. Flood forces in the Coastal A 

Zone are not as severe as in Zone V, but 

are still capable of damaging or destroying 

buildings on shallow foundations. During 

base flood conditions, the potential for wave 

heights is greater than or equal to 1.5 feet, 

but less than 3.0 feet. For this reason, different design and construction standards are 

recommended (by the MAT and others) in 

the Coastal A Zone than in the riverine Zone 

A. Coastal A Zone provisions are included in 

ASCE 24-05 and ASCE 7-05, which are referenced by model building codes.

Shaded Zone X. Areas having between a 

1-percent and 0.2-percent annual chance of 

flooding.

Unshaded Zone X. Areas with less than 0.2-

percent annual chance of flooding.
2-4 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

2 FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS

For buildings built in Zones B, C, and X (areas of moderate or minimal hazard from the 

principal source of flood in the area), there are no NFIP building requirements, even for 

buildings built on barrier islands, because these buildings are outside the SFHA. 

2.1.1.1 Accuracy of Flood Insurance Studies and Flood Insurance Rate Maps 

It is important to note that the limits of the SFHA, the area over which floodplain management 

regulations apply, have changed over the past three decades as new FISs have been completed, 

BFEs have been changed, and new FIRMs have been issued. These changes affect the lowest 

building floor elevations mandated within the SFHA. 

Figure 2-2. Relationship between the stillwater elevations, BFE, wave effects, and flood hazard zones

Figure 2-3. 

Elevation of residential structures 

to the BFE is required in Zone V. The 

MAT recommends elevating higher, or 

adding freeboard (see Sections 2.1.1.3, 

3.1.3, and 7.1.1).
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 2-5

FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS 2

Any SFHA and BFE changes are generally the result of one or more of the following: 

n Changed conditions on the ground 

n FISs and resulting FIRMs are based 

on physical, hydrologic, and hydraulic 

conditions existing at the time of 

the study. They do not anticipate 

or account for future changes in 

conditions (e.g., shoreline erosion, 

land subsidence, changed drainage 

patterns, etc.). Thus, as conditions 

change over time, the lateral and vertical extents of the base flood will deviate 

from those shown on the FIRM, and the FIRMs may no longer represent the best 

estimate of the SFHA and BFE.

n A longer period of record with which to characterize regional hurricane characteristics

n FISs and resulting FIRMs are based on the record of hurricanes at the time the study 

is conducted. Statistical distributions of important storm parameters (e.g., central 

pressure, radius to maximum winds, forward speed, direction, etc.) are developed 

from the record and are used as inputs to storm surge models. As time passes, more 

and more hurricanes occur that may not be represented in our statistics, and the FIRM 

becomes a less accurate predictor of the base flood.

n New flood study models and procedures

n All FIRMs are generated using available 

topographic and land use data, and 

FEMA-approved study procedures 

and models. Those data, procedures, 

and models, however, are imperfect. 

They approximate the terrain and 

the physical processes that occur 

during a flood event. In an effort to 

improve map accuracy, FEMA, States, 

and communities now gather more 

accurate topographic and land use data than in years past. Also, FEMA has updated 

study procedures and models over the years to improve their ability to represent 

dune erosion, storm surge propagation, and wave effects. Taken together, improved 

terrain data and study methods used now yield more accurate BFE and SFHA estimates 

than in years past. However, even newer maps created with improved models and 

procedures have some uncertainty. This uncertainty can be addressed by adopting 

beyond-minimum flood-resistant design and construction practices, such as requiring 

freeboard (ASCE 24 is one source for guidance on freeboard). 

FEMA’s Community Status Book provides 

the date of the effective FIS and FIRM for 

all mapped communities 

(http://www.fema.gov/fema/csb.shtm).

The FIS and FIRMs can be viewed through 

the Product Catalog at FEMA’s Map 

Service Center site. (http://msc.fema.gov/). 

A new FIS for southwest Louisiana was 

just completed using the latest data, procedures, and models, and preliminary 

DFIRMs were released between January 

and November 2008 (see http://www.lamappingproject.com/).

A new FIS for coastal Texas is now underway, and preliminary DFIRMs are expected 

to be released within a year.
2-6 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

2 FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS

2.1.1.2 Implication of FIRMs on Rebuilding and Building Safety

It is important to understand the limitations of FIRMs when considering reconstruction or new 

construction after a storm. The information described in Section 2.1.1.1 has the following implications for communities and homeowners:

n Since BFEs shown on future FIRMs may be higher, buildings constructed to elevations 

shown on Effective FIRMs may be constructed at elevations below those future BFEs.

n Buildings originally constructed outside the SFHA may be located within future SFHAs, but 

without the benefit of flood-resistant construction techniques.

n Even if the FIRM predicted flood levels perfectly, buildings constructed to the elevations 

shown on the FIRM will offer protection only against the 1-percent annual chance flood 

level (BFE). Some coastal storms will result in flood levels that exceed the BFE, and 

buildings constructed to the minimum elevation could sustain flood damage. 

2.1.1.3 Higher Regulatory Standards 

One of the most effective ways to compensate for future conditions, changed flood hazards, and 

floods exceeding the 1-percent annual chance flood level is to elevate buildings above the BFE 

shown on the FIRM at the time of construction. This practice is called “adding freeboard,” and it not 

only reduces future flood damage, but results in significantly lower flood insurance premiums. 

A comprehensive study of freeboard (American Institutes for Research, 2006) demonstrated 

that adding freeboard at the time of house construction is cost-effective. Reduced flood damage yields a benefit-cost ratio greater than 1 over a wide range of scenarios, and flood insurance 

premium reductions make adding freeboard even more beneficial to the homeowner. Reduced 

flood insurance premiums will pay for the cost of incorporating freeboard in a Zone V house in 

1 to 3 years; in a Zone A house, the payback period is approximately 6 years. 

2.2 Building Codes and Standards

Model building codes have long included requirements for designers to identify anticipated environmental loads and load combinations, including wind loads, seismic loads, snow loads, and 

soil conditions. The 2000, 2003, and 2006 editions of the IBC and the International Residential Code (IRC), and the 2003 and 2006 editions of the National Fire Protection Association’s 

(NFPA) Building Construction and Safety Code (NFPA 5000) are the first model codes to include 

FREEBOARD

Some communities visited by the MAT require freeboard above the BFEs

n Texas Floodplain Management Association’s freeboard survey is available at http://www.tfma.org/.

n The eight Louisiana parishes visited by the MAT have adopted freeboard consistent with Rita or 

Katrina Flood Recovery and ABFE maps (http://www.lamappingproject.com/).
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 2-7

FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS 2

comprehensive provisions that address flood hazards. 

These codes are consistent with the minimum provisions 

of the NFIP that pertain to the design and construction 

of buildings.

International Building Code

The IBC is a performance and prescriptive code that, 

for the most part, requires buildings and structures to be 

individually designed to meet the requirements of the 

code and various referenced standards. The two referenced standards (ASCE 7-05 and ASCE 24-

05) that include provisions pertaining to flood hazards are briefly described in Sections 2.2.1.2 

and 2.2.1.3. According to Mehta et al., (2007, pg. 32), in a performance code, the performance 

criteria of a component are specified instead of the material or the construction system. The 

performance criteria are based on the function of the component. The older and traditional 

types of building codes are prescriptive codes. Such codes give the prescription for construction 

systems, types of materials, and the devices to be used without permitting any alternatives.

International Residential Code

The IRC addresses environmental loads in a more prescriptive approach so that many one- and 

two-family houses can be built without individual designs prepared by architects and engineers. 

Texas Statewide Residential Building Code 

The statewide residential building codes in Texas are the 2000 IRC and the 1999 National Electrical Code (NEC). These, however, may be amended in local jurisdictions if they have updated 

the code provisions. The code that applies to an unincorporated area is the same code adopted 

by the county seat. If the county seat has not adopted an updated version of the code, then the 

2000 IRC applies and code enforcement falls under the jurisdiction of the Texas Residential 

Construction Commission (TRCC).

Texas Residential Construction Commission

The TRCC develops and maintains building and performance standards for residential construction in Texas. These standards are not the same as a building code. A building code dictates how 

a builder must build a house. The building and performance standards apply to how a house 

must perform after it is built. The commission-adopted building and performance standards 

apply to residential construction that began in Texas on or after June 1, 2005. Residential construction completed before June 1, 2005, is governed by the standards applicable to the project 

at the time of the construction. The commission-adopted standards include compliance with 

the 2000 IRC and the 1999 NEC (TRCC, 2005). 

In August 2008, the Texas Sunset Advisory Commission, which was created in 1977 by the Legislature to identify and eliminate waste, duplication, and inefficiency in government agencies, 

called for the TRCC to be abolished and stated that its “current regulation of the residential 

construction industry is fundamentally flawed and does more harm than good” (Dallas Business 

NOTE

The 2009 edition of the IRC will 

require 1 foot of freeboard in Zone 

V and the Coastal A Zone.
2-8 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

2 FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS

Journal, 2008). On September 1, 2008, in response to the Sunset Advisory Commission, the 

TRCC began enforcing an amendment to the Texas Register that had been previously approved 

in February 2008. This amendment requires the enforcement of the IRC for residential construction completed by builders and remodelers in unincorporated areas or in areas not subject 

to municipal inspections to have a minimum of three inspections: 1) a foundation inspection; 

2) a framing, mechanical, and delivery systems inspection; and 3) a final inspection.1

 This 

three-step process provides inspection by a qualified third-party architect, engineer, or building 

official and is intended to ensure compliance with the requirements of the IRC. However, unincorporated areas of Texas are not required to complete plan review, residential building design 

review, or building inspection by a State or county building official.

Louisiana Statewide Uniform Construction Code 

The Louisiana Legislature enacted Act 12 of the 2005 First Extraordinary Session to provide for 

a State uniform construction code to govern new construction, reconstruction, and additions 

to previously constructed homes in 11 coastal parishes. Act 12 mandated adoption of the latest 

editions of the IBC and IRC (subject to some amendments by the State) and created the Louisiana Statewide Uniform Construction Code Council (LSUCCC) to update statewide code as new 

editions of the IBC and IRC are published.2

2.2.1 Flood Requirements

The following discussion provides information regarding flood requirements in building codes 

and the national consensus standards that are incorporated into the codes. The flood-related 

code provisions discussed generally apply in Louisiana and Texas.

2.2.1.1 Flood Requirements in the IBC and IRC

IBC. The IBC applies to multi-family buildings (with a few exceptions) and to non-residential 

buildings. In the terminology of the NFIP, the IBC is used for engineered structures. The 2006 

IBC addresses flood loads and flood-resistant construction primarily in Section 1612, Flood 

Loads, which refers to the consensus standards ASCE 7-05 and ASCE 24-05 (refer to Section 

2.2.1.2 and 2.2.1.3 for information on ASCE). Most of the mandatory flood provisions are 

contained in Section 1612, but others occur in the code related to the lowest floor elevation 

inspection, flood-resistant materials, accessibility, ventilation, and elevators (IBC 2006). Flood 

loads and load combinations are specified in Section 1605, Load Combinations (IBC 2006). 

The designer must identify the pertinent, site-specific characteristics and then use ASCE 7-05 to 

determine the pertinent specific loads and load combinations. In effect, it is similar to a local 

floodplain ordinance that requires determination of the environmental conditions (location of 

building with respect to mapped flood hazard area, effective BFE, and flood depth) and then 

specifies certain conditions that must be met during design and construction. The body of the 

IBC, together with Appendix G, Flood-Resistant Construction, addresses all of the key building 

and development requirements of the NFIP. If communities participate in the NFIP, they should 

1 http://www.trcc.state.tx.us/policy/FAQs_2.asp#countyinspections

2 See http://www.dps.louisiana.gov/lsuccc/codes.html for the latest Louisiana code information
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 2-9

FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS 2

coordinate their floodplain ordinances with the I-Codes (both IBC and IRC) to ensure that all 

requirements are addressed.

IRC. The scope of the IRC is more limited than the IBC. The IRC applies to one- and two-family 

dwellings and to some townhouses. In the terminology of the NFIP, the IRC is used for residential structures. The IRC addresses flood-resistant construction primarily in Section R324, 

Flood-Resistant Construction, although provisions for mechanical and plumbing installations 

are included in other pertinent sections of the 2006 IRC. 

It is important that communities coordinate their ordinances with the I-Codes (both IBC and 

IRC) to ensure that all requirements are addressed. A crosswalk of the NFIP regulations and the 

I-Code provisions is provided in FEMA 9-0372.

IBC/IRC Commonalities. There are some commonalities between the IBC and the IRC as they relate to NFIP:

n Both specify information related to SFHAs that are to be included in permit applications 

and shown on plans.

n Both specify that an inspection is required upon placement of the lowest floor, including 

basement, and prior to further vertical construction, at which time the building official 

is to require submission of documentation, prepared and sealed by a registered design 

professional or surveyor, of the elevation of the lowest floor, including the basement.

2.2.1.2 Flood Requirements in ASCE 7-05

The ASCE develops and maintains the consensus standard for ASCE 7-05 (2005b). Since the 

1995 edition, ASCE has included flood load provisions. The provisions have changed with each 

succeeding edition. ASCE 7-98 is a referenced standard in the 2000 and 2003 editions of the 

IBC, and the 2006 edition of the codes refers to ASCE 7-05.

Design loads used by the 2003 IBC are taken from ASCE 7-02. The following sections of ASCE 

7-05 deal with flood:

n Section 2.3, Combining Factored Loads Using Strength Design, and Section 2.4, 

Combining Nominal Loads Using Allowable Stress Design, include load combinations for 

Zone V and Coastal A Zone.

n Chapter 5, Flood Loads, covers hydrostatic, hydrodynamic, wave, and impact loads. Load 

criteria for breakaway walls are included in Section 5.3.3.

The standard requires designers to determine if a site is susceptible to erosion (general lowering of the ground surface) or scour (localized lowering due to interaction of waves and currents 

with a building element). 

In recognition of the growing awareness that wave heights between 1.5 feet and 3.0 feet (the latter being the lower cutoff used to delineate FEMA’s Zone V) cause considerable damage, ASCE 

7-05 incorporates the concept of the Coastal A Zone. 
2-10 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

2 FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS

The 2006 edition of the IRC does not refer to ASCE 7-05 for flood loads because the code is 

a prescriptive code that, for the most part, does not require individual designs for buildings 

that are built in compliance with the provisions of the code. However, for buildings located in 

Zone V, individual designs for buildings must be prepared and sealed by a registered design 

professional.

2.2.1.3 Flood Requirements in ASCE 24-05

The ASCE develops and maintains the consensus standard for ASCE 24-05, Flood Resistant Design 

and Construction (2005a). The first edition of ASCE 24 was published in 1998 and is referenced 

in the 2000 and 2003 editions of the IBC. The 2005 edition of ASCE 24 is a major revision and 

expansion of the standard, and is referenced by the 2006 IBC. 

ASCE 24-05 specifies minimum requirements for flood-resistant design and construction of 

buildings and structures located in flood hazard areas, including floodways, Coastal High Hazard 

Areas, and other high-risk flood hazard areas, such as alluvial fans, flash flood areas, mudslide 

areas, erosion-prone areas, and high velocity areas. It applies to new structures and substantial 

repair or improvement of existing structures that are not designated as historic structures. Basic 

design requirements address flood loads and load combinations, elevation of the lowest floor, 

foundation requirements and geotechnical considerations, use of fill, and anchoring and connections. As a function of the type of flood hazard area, enclosures are to have breakaway walls 

or meet requirements for flood openings (prescriptive or engineered). 

For buildings in coastal high hazard areas (Zone V) and Coastal A Zone, ASCE 24-05 includes 

specifications for the design of pile, post, pier, column, and shear wall foundations. Considerable detail is specified for pilings as a function of pile types and connections. 

Additional sections of ASCE 24-05 include the following elements: materials, dry and wet floodproofing, utility installations, building access, and miscellaneous construction (decks, porches, 

patios, garages, chimneys and fireplaces, pools, and above- and below-ground storage tanks). 

Section 1612.4 of the 2006 IBC states, “The design and construction of buildings and structures 

located in flood hazard areas, including flood hazard areas subject to high velocity wave action, 

shall be in accordance with ASCE 24.”

The 2006 IRC does not refer to ASCE 24-05 because the code is a prescriptive code that, for the 

most part, does not require individual designs for buildings that are built in compliance with 

the provisions of the code. The exceptions for Zone V buildings (which do require design) were 

listed above. Communities must, therefore, reference ASCE 24-05 directly to apply its provisions 

to residential buildings. However, Section R324 of the 2006 IRC, Flood-Resistant Construction, 

states that buildings in floodways shall be designed in accordance with the IBC, thereby mandating use of ASCE 24-05 for buildings in floodways as shown on the FIRMs. Also, the 2009 IRC will 

allow use of ASCE 24-05 as an alternative to certain provisions of the IRC.
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 2-11

FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS 2

2.2.1.4 Flood Requirements in Texas

Flood requirements in Texas are specified at the community level. There are no additional 

State-mandated flood standards. The Texas Water Development Board3

 is the State coordinating agency for the NFIP. 

2.2.1.5 Flood Requirements in Louisiana

Flood requirements in Louisiana are specified at the community level. There are no additional 

State-mandated flood standards. The Louisiana Department of Transportation and Development 

(LADOTD)4

 is the State coordinating agency for the NFIP, and produced a Louisiana Floodplain 

Management Desk Reference summarizing floodplain management in the State (LADOTD, 

2008). 

2.2.2 Wind Requirements

Wind speeds and wind damage were more significant in Texas than Louisiana. The wind investigation and analysis was primarily limited to Texas. The following discussion provides information 

regarding wind requirements in codes and information about code adoptions in Texas and 

Louisiana. 

2.2.2.1 Wind Requirements in the IBC

The methodology required for calculating wind loads in the 2006 IBC is that prescribed in 

Chapter 6 of ASCE 7-05. Using ASCE 7-05 for determining wind loads ensures that designers are 

using state-of-the-art methodology to calculate wind loads. In addition to improved load computations, ASCE 7-05 also provides performance and testing requirements for windborne debris 

protection of glazing in compliance with ASTM E 1886, Standard Test Method for Performance of 

Exterior Windows, Curtain Walls, Doors, and Impact Protective Systems Impacted by Missile(s) and 

Exposed to Cyclic Pressure Differentials, and ASTM E 1996, Standard Specification for Performance of 

Exterior Windows, Glazed Curtain Walls, Doors, and Storm Shutters Impacted by Windborne Debris in 

Hurricanes.

2.2.2.2 Wind Requirements in Texas

Texas counties and municipalities have the authority to adopt a building code of their choosing. 

Historically, in the State of Texas, the codes of choice were the Standard Building Code (SBC) 

and the Uniform Building Code (UBC), with the SBC being the preferred code in the coastal 

counties. With the advent of the I-Codes in 2000, most counties had adopted the IRC and the 

IBC prior to Hurricane Ike. As of September 1, 2008, the TRCC requires unincorporated areas 

within counties to comply with the 2000 IRC, at a minimum. If a county seat has adopted an updated version of the IRC code, that code applies to the unincorporated areas within the county. 

Table 2-1 lists those counties affected by Ike and their adopted codes.

3 http://www.twdb.state.tx.us/wrpi/flood/nfip.htm

4 http://www8.dotd.la.gov/lafloods/
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2 FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS

Table 2-1. Codes in Effect at the Time of Hurricane Ike for Impacted Counties and Cities in Texas

County City Building Codes*, **

Brazoria County

Surfside Beach 2003 IBC and IRC

Chambers County

Baytown 2006 IBC and IRC

Galveston County

Clear Lake Shores 2003 IBC and IRC

City of Galveston 2003 IBC and IRC

Jamaica Beach 2006 IBC and IRC

Village of Tiki Island 2000 IBC and IRC

Kemah 2003 IBC and IRC

Texas City 2003 IBC and IRC

League City 2000 IBC and IRC

Harris County

Houston 2000 IBC and IRC

La Porte 2003 IBC and IRC

Deer Park 2003 IBC and IRC

Seabrook 2003 IBC and IRC

Shoreacres 2000 IBC and IRC (2006 IBC and 

IRC adopted after Hurricane Ike)

Jefferson County

Beaumont 1997 SBCCI

Port Arthur 2006 IBC and IRC

Port Neches 2003 IBC and IRC

Orange County

Bridge City 2006 IBC

Orange 2003 IBC and IRC

Notes:

* IBC – International Building Code

IRC – International Residential Code

SBCCI – Southern Building Code Congress International

** The current adopted code should be verified before construction or rebuilding activities commence. 
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 2-13

FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS 2

All versions of IBC specify higher wind speeds for coastal Texas counties than any of the previous 

editions of the SBC. Therefore, variation exists in the design wind speeds for areas throughout 

those counties for buildings previously constructed to the SBC standard. The 1985 SBC modified the required speeds to match those in the American National Standards Institute (ANSI) 

A58.1-1982 standard, the predecessor to the ASCE 7, but rejected the inclusion of the new methods and coefficients for calculation pressures included in the ANSI standard. The wind speed 

map remained unchanged for all subsequent editions of SBC, including the last edition in 1999. 

The maps used by the 2003 IBC are taken directly from ASCE 7-02. The 3-second gust wind 

speeds cited in the 2003 IBC for Galveston, Chambers, and Harris Counties increased significantly from those cited in the 1997 SBC. Table 2-2 summarizes the progression over time of the 

basic design wind speeds for those counties. The map shown in Figure 2-4 includes an overlay 

of design wind speed contours for the portion of the Texas and Louisiana coast affected by Hurricane Ike and was taken directly from the 2003 IBC/ASCE 7-05. The colored swaths provide a 

graphical representation of the percentage difference between Hurricane Ike’s peak 3-second 

gusts compared to these design speeds. This map clearly indicates that Hurricane Ike’s winds 

were less than the required design wind speeds for buildings in this region.

Table 2-2. Approximate Range of Basic Design Wind Speeds in the Coastal Counties Visited by the MAT (3-Second 

Gust, Exposure C, at 33 Feet Above Ground) 

County SBC 1985 Edition* SBC 1997 Edition* 2006 IBC and ASCE 

7-02 and Later

Galveston 115–120 mph 110–120 mph 120–130 mph

Chambers 110–115 mph 110–115 mph 110–125 mph

Harris 100–110 mph 100–110 mph 100–110 mph

* Code wind speeds reported as fastest-mile wind speeds in the Standard Building Code (SBC) were converted to 3-second gust 

for comparison. The lower values correspond to the edge of the county farthest from the coast, and the higher values correspond 

to the coastal value or the edge of the county closest to the coast. 

IBC = International Building Code

ASCE = American Society of Civil Engineers 
2-14 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

2 FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS

Figure 2-4. 

Comparison of ASCE 7-05 

and Ike gust wind speeds
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 2-15

FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS 2

Example of Design Load Changes Over Time

The SBC expressed wind speeds in terms of the “fastest mile,” whereas the IBC and ASCE 7 

measures maximum wind speeds as “3-second gusts” (refer to text box). Table 2-3 presents a 

summary of the design wind pressures on wall and roof areas for a typical residence in the City 

of Galveston, and compares the wind pressures with respect to the 1985 SBC fastest mile measurement, the 1997 SBC 3-second gust (converted from fastest mile) measurement using an 

ASCE 7-95 design solution and the current adopted 2006 IBC 3-second gust measurement. The 

IBC calculations are based on a home less than 33 feet tall and located near the water in Exposure C. The required design pressures are given for both a building’s structure (referred to in 

codes and standards as the main wind force resisting system or MWFRS) and for a building’s envelope (referred to as components and cladding, or C&C). The 1985 SBC uses the terminology 

of “Parts and Portions” (P&P) in lieu of the current ASCE 7 terminology of C&C. The 1985 SBC 

design coefficients did not address pressures for MWFRS corners or P&P coefficients for roof 

and corner edges. Though the 1985 SBC references and allows the use of the ANSI standard 

(ANSI A58.1-1982), the new design load standard and predecessor of ASCE 7 of that time, the 

City of Galveston did not adopt the ANSI standard.

COMPARING BASIC DESIGN WIND SPEEDS

Current codes and standards (2006 IBC and ASCE 7-05) standardize wind speed measurement as 

the 3-second gust. This differs from the fastest-mile wind speed measure that was previously used by 

the SBC, as well as the wind speed measure of 1-minute sustained that is used in the Saffir-Simpson 

Hurricane Scale and referenced by the NHC. The Saffir-Simpson Hurricane Scale was presented in 

Table 1-2. The table below provides a comparison of wind speeds for 3-second gust, fastest mile, and 

1-minute sustained. 

Wind Speed Comparison (in miles per hour)

*V3-second gust 85 90 100 110 120 130 140 150

*Vfastest-mile 70 75 80 90 100 110 120 130

**Vsustained 67 71 79 87 95 102 110 118

* 3-second gust and fastest mile based on 2003 IBC table 1609.3.1.

** 1-minute sustained based on the Engineering Sciences Data Unit gust factor curve.
2-16 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

2 FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS

Table 2-3. Design Loads for a Typical Single-Family Residence in the City of Galveston, Galveston County, TX 

Description SBC 1985 Edition SBC 1997 Edition

(ASCE 7-95 Solution) 2006 IBC and ASCE 7-05

Basic Design Wind 

Speed

100 mph

(fastest-mile, fm)

120 mph

(fm converted to 

3-second gust)

130 mph

(3-second gust)

Wind Design Pressures on Exterior Walls (psf)

As MWFRS:

Windward

Leeward

Net Horizontal

+19/+14

-12/-7

+31

+29/+16

-20/-8

+37

+30/+17

-21/-9

+39

As C&C:

Middle

Corner

+26/-26

*

+36/-41

+36/-49

+39/-43

+39/-51

Wind Design Pressures on Roof (4:12 slope) (psf)

As MWFRS:

Windward 

Leeward

-22/-18

-17/-12

-18/-5

-20/-8

-23/-10

-23/-11

As C&C:

Middle

Corner

Overhang Middle

Overhang Corner

*

*

-36

*

+16/-53

+16/-55

-73

-83

+27/-64

+23/-80

-75

-127

Definitions:

SBC = Standard Building Code

ASCE = American Society of Civil Engineers

IBC = International Building Code

mph = miles per hour

Notes:

The sampled residence is 40 feet by 40 feet, elevated on 10 pilings, with a total roof eave height of 20 feet. The roof is gable with 

the winds calculated normal to the roof ridge line. The roof slope is a 4:12 pitch. Calculations use the SBC and ASCE 7 method for 

buildings of all heights. Wind speeds were selected from the 50-year Mean Recurrence Maps from the respective code or standard. 

Calculations are based on Exposure C wind speeds measured at 33 feet (10 meters) above ground level.

* Load considerations and pressure coefficients not included in the SBC 1985 Edition.

1. The pressure calculations under each code for both MWFRS and C&C were calculated using building design coefficients that provide the maximum wind pressure for that area on the building surface.

2. Previous and current U.S. building codes and ASCE standards do not address pressures on the underside of floors for open elevated structures.

3. Positive pressure values indicate pressure acting inward toward building surfaces. Negative value pressures indicate pressures acting outward from building surfaces.

4. The building was considered to be an enclosed structure subject to positive and negative internal pressures and the values tabulated represent the maximums per evaluated area. 

5. Numbers divided by a slash (/) represent the effect of positive and negative pressure coefficients.

6. The net horizontal pressures consider the addition of the positive windward pressures and negative leeward pressures with the internal pressures canceled.

psf = pounds per square foot

MWFRS = Main Wind Force Resisting System

C&C = Components and Cladding
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 2-17

FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS 2

2.2.2.3 Wind Requirements in Louisiana

Prior to Hurricane Katrina, Louisiana communities had various building and residential codes, 

and, in many communities, no codes at all. The State Uniform Construction Code, which took 

effect on January 1, 2004, required only that communities choosing to enforce a code use the 

2000 IBC. Many larger cities and parishes adopted the IBC, but many other communities had 

not adopted the IBC, and were still enforcing various editions of the SBC. There were no Statelevel provisions relating to residential building codes. When adopted, the form and guidance 

provided by these residential codes varied widely, including various editions of the IRC, SBC, 

and Council of American Building Officials (CABO) codes. This lack of a residential code, or 

use of older versions of the residential codes, is often an indicator that the residential buildings in the areas were designed and constructed without the guidance and criteria of the newer 

hazard-resistant codes.

After Hurricane Katrina, the Louisiana State Legislature passed Act 12 on November 29, 2005, 

requiring enforcement of the IBC and IRC statewide. It also created the Louisiana State Uniform Construction Code Council, whose purpose is to “... review and adopt the state uniform 

construction code, provide for training and education of code officials, and to accept all requests for amendments to the code, except the Louisiana State Plumbing Code.” The provisions 

of the newly revised State Uniform Construction Code were to be implemented in phases. The 

new law contained emergency provisions requiring Calcasieu, Cameron, Iberia, Jefferson, Lafourche, Orleans, Plaquemines, St. Bernard, St. Tammany, Terrebonne, and Vermilion Parishes 

to enforce all wind and flood mitigation requirements prescribed by the 2003 IBC and IRC, as 

modified and amended by Section 301.2.1.1(2) to replace SBCCI Standard for Hurricane-Resistant 

Construction (SBCCI SSTD 10-99) with the Guidelines for Hurricane-Resistant Residential Construction as published by the IBHS in 2005.

2.2.3 HUD Manufactured Housing Design Standards 

The design and construction of manufactured homes have been governed at the Federal level 

by the U.S. Department of Housing and Urban Development (HUD) since the National Manufactured Housing and Construction Safety Standards Act was passed in 1974. 

Beginning in 1976, the Manufactured Home Construction and Safety Standards, Title 24 of 

the Code of Federal Regulations (CFR) Part 3280, established the minimum requirements for 

the construction, design, and performance of a manufactured home. HUD, rather than States 

or communities, determines the manufacturing standards for manufactured homes. However, 

States and communities determine where manufactured housing can be sited and what permits 

and inspections are required for installation and occupancy of manufactured housing.

Currently, the HUD standards define a manufactured home as a dwelling unit, transportable in 

one or more sections, that, when erected on site, is of at least 320 square feet in size, with a permanent chassis to ensure the initial and continued transportability of the home. In the traveling 

mode, a manufactured home is 8 feet or more in width or 40 feet or more in length. 
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2 FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS

In August 1992, when Hurricane Andrew hit southern Florida, over one-third of all site-built 

houses were substantially damaged and almost all manufactured homes were destroyed within 

the area affected by the hurricane. As a direct consequence, HUD developed improved windresistance requirements for the hurricane-prone coastal areas of the United States. Published as 

a Final Rule in the Federal Register (59 FR 2456 [1994]), these changes introduced more stringent requirements in high wind areas and defined three separate wind zones: Zone I, Zone II, 

and Zone III. 

For wind Zones II and III, this rule also designates higher wind loads. Specifically, the updated 

HUD standard requires that the manufactured home, each of its wind-resisting parts, and its 

C&C materials be designed by a professional engineer or architect to resist either the design 

wind loads for Exposure C specified in ANSI/ASCE 7-88, Minimum Design Loads for Buildings 

and Other Structures, for a 50-year recurrence interval or those tabulated in 24 CFR Part 3280. 

Zone II homes must be designed to resist a fastest-mile wind speed of 100 mph; Zone III homes 

must be designed to resist a 110 mph fastest-mile wind speed. Zone I homes are not specifically 

associated with a design wind speed, but rather are designed to resist minimum horizontal and 

vertical wind pressures.

In addition, the rule requires that each manufactured home have a support and anchoring or 

foundation system that, when properly designed 

and installed, will resist overturning and lateral 

movement (sliding) of the manufactured home, 

as imposed by the respective design loads.

Manufactured home regulations and standards are continuously being developed. The following list summarizes some of the more recent regulations and standards that have been passed 

or developed:

n The HUD Manufactured Housing Installation Standard, 24 CFR Part 3285, was issued 

in October 2007 and became effective October 20, 2008. This standard is part of an 

installation program that includes: (1) installation standards, (2) training and licensing 

manufactured home installers, and (3) inspecting manufactured home installations. The 

HUD program will be mandated for any State that does not have its own program that 

includes all three of the previously described components. To be exempted, a State must 

have adopted standards that equal or exceed the protection provided by HUD’s program.5

n The NFPA currently maintains three documents on the subject of manufactured housing: 

(1) NFPA 501, Standard on Manufactured Housing, a consensus document on the design 

and construction of manufactured homes (NFPA, 2005b); (2) NFPA 501A, Standard for Fire 

Safety Criteria for Manufactured Home Installations, Sites and Communities (NFPA, 2009b); 

and (3) NFPA 225, Model Manufactured Home Installation Standard, a consensus document 

that governs the installation of manufactured homes (NFPA, 2009a). The 2005 edition 

of NFPA 501 has wind-related requirements based upon ASCE 7-02. The 2009 edition of 

Please note that the September 1985 edition of FEMA 85, Manufactured Home 

Installation in Flood Hazard Areas, is currently under revision and is tentatively 

scheduled to be released later in 2009.

5 More information on the development of this new program can be found at http://www.hud.gov/offices/hsg/ramh/mhs/mhip.cfm
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 2-19

FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS 2

NFPA 225 has wind provisions consistent with ASCE 7-05 and flood provisions consistent 

with the NFIP. The latest edition of NFPA 225 also contains new prescriptive flood- and 

wind-resistant foundation designs.

2.2.3.1 Manufactured Housing in Texas

The Manufactured Housing Division of the Texas Department of Housing and Community Affairs adopted amendments to Texas Administrative Code (TAC), Chapter 80, Sections 80.2, 

80.21, and 80.22, related to installation standards of the manufactured housing program. These 

amendments comply with the Federal Installation Standards (24 CFR Part 3485) that became 

effective January 1, 2009. 

The Texas codes require that all new manufactured homes be installed by a licensed installer in 

accordance with the home manufacturer’s approved installation instructions. The installer of a 

new manufactured home is responsible for the proper preparation of the site where the manufactured home will be installed. 

The codes require that all used manufactured homes be installed by a licensed installer to resist 

overturning and lateral movement of the home and in accordance with instructions appropriate 

for the wind zone where the home is to be installed as per the home manufacturer’s installation 

instructions; the State’s generic standards set forth in Sections 80.22 through 80.25 of Chapter 

80; the instructions for a stabilization system registered with the Department in accordance with 

Section 80.26 of Chapter 80; or the instructions for a special stabilization system. 

2.2.3.2 Manufactured Housing in Louisiana 

The State of Louisiana has adopted the Manufactured Home Installation Standards – Final Rule 

contained in 24 CFR Part 3285 for the installation of new manufactured homes. In the Final 

Rule, all new manufactured homes must be installed to the new standard at the initial installation. The manufacturer’s instructions apply where the manufacturer’s approved instructions 

meet or exceed this standard and do not take the home out of compliance. 

Prior to initial installation of a new manufactured home, the installer is responsible for determining whether the manufactured home site lies wholly or partially within a flood hazard area 

(24 CFR 3285.102). If the property where the home is to be installed is located within a flood 

zone, 24 CFR Part 3285 requires the installation to satisfy the NFIP. The Final Rule at 24 CFR 

Part 3285 also requires that manufacturer’s installation instructions specifically state whether 

they are appropriate for homes placed in SFHAs or not.

For existing homes, Louisiana follows the Louisiana Revised Statutes (R.S.) 51:912.21. In the absence of manufacturer’s installation instructions, homes must be placed in accordance with R.S. 

51:912.21 through 51:912.31. Louisiana statutes require the landowner to be responsible for 

proper site preparation. The statutes also require that the grade under the home be cleaned of 

all vegetation and organic material, and sloped to properly drain. All grass and organic material 

must be removed and the pier foundation placed on stable soil or compacted fill. The statutes 

also specify minimum requirements for the pads or footers supporting the piers. In floodprone 
2-20 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

2 FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS

areas, the foundation is required to comply with the requirements set forth in FEMA 85, Manufactured Home Installation in Flood Hazard Areas (FEMA, 1985).

2.2.4 Galveston Residential Hurricane Resistance Study, 1990 

During the last decade, new information has been learned about the effects of hurricane wind 

and flooding, and this knowledge has been incorporated into building codes and construction practices. In 1990, a study titled Effectiveness of Building Codes and Construction Practice in 

Reducing Hurricane Damage to Non-Engineered Construction was conducted by James R. McDonald, PhD, P.E. of the TTU Institute for Disaster Research and Billy Manning, P.E. of SBCCI. 

The scope of work was to examine the history of the wind and flood design provisions of the 

City of Galveston, TX, building code and to determine the effectiveness of building codes and 

construction practices in reducing hurricane damage to non-engineered construction. Thirtyone single-family residences constructed under various eras of building code authority were 

examined. The information collected included terrain exposure, floor elevation, construction 

practices, quality of workmanship and materials, state of repair, insurance coverage, and damage from previous hurricanes. The MAT’s review and investigation of some of the buildings 

analyzed in the 1990 Galveston study provides insight into an important question: whether 

the continued observed vulnerability of buildings from hurricanes results from an incomplete 

understanding of design or construction issues or the lack of incorporating these design and 

construction practices into new construction and retrofit buildings.

Ten code eras were identified, beginning with the first Galveston code adoption in 1914 and 

ending with the effective code at the time the study was conducted. The codes concurrent with 

the Galveston study were the SBC (1985 edition with the 1986 revisions, published by SBCCI) 

and the 1971 Texas Catastrophe Property Insurance Association (TCPIA) wind load provisions. 

The TCPIA wind code applied to the first two tiers of counties along the Gulf Coast of Texas, 

including Galveston (refer to Section 2.3.2 for more information). In order to obtain extended-coverage insurance, a building owner had to have certification that the property met the 

TCPIA requirements.

The locations of the houses investigated in the Galveston study are shown in Figure 2-5. The newest house, number 3289, was still under construction at that time, which allowed for a thorough 

investigation of building connections and construction quality. The remaining 30 houses had 

been constructed prior to the study, and the building connections could not be thoroughly examined. Attics were inspected and the type of rafter-to-wall connections noted, either toe-nailed 

or hurricane clips. Of the 31 houses, seven were observed to have hurricane clip connections. 

A roof uplift resistance analysis was run on each house based upon the observed quality of construction, the roof anchorage, rafter size and spacing, and the roof decking. Those results were 

then compared to the current Galveston code, SBC, and ASCE 7-88 uplift forces associated to 

the same assigned wind speed of 96 mph, fastest-mile (117 mph, 3-second gust).

The City of Galveston adopted the NFIP’s FIRMs on May 7, 1971. Based on the results of a wave 

analysis that FEMA conducted for the City, the FIRMs were revised in 1983 and remained current 
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 2-21

FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS 2

at the date of the 1990 Galveston study. As a part of the investigation of susceptibility of the 31 

houses for flooding and surge damage, the following information was recorded for each:

n Flood zone

n BFE

n Elevation of lowest floor

n Distance to water

n Closest body of water

n Foundation type

n Connections of elevated structure

Figure 2-5. 

Galveston Island houses investigated for the 1990 report that were visited by the MAT in 2008 after Hurricane Ike
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2 FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS

The observations included in the Galveston study 

noted that many of the houses constructed preFIRM were constructed at or within 1 foot of the 

mapped BFE. All of the houses constructed postFIRM were sited above the BFE and appeared 

to have more substantial pile foundations than 

the older residences, and had more substantial 

anchorage between the piles, girders, and floor 

joists.

The overwhelming conclusions of the Galveston 

study regarding wind resistance were that most 

wood-framed residences did not meet the performance criteria of building codes and roof-to-wall 

connections were not designed or analyzed for 

resistance to wind uplift forces. Other conclusions were that the practice of using toe-nailed 

connections is unsatisfactory, and that hurricane clips can provide the needed resistance, 

but their selection must be based upon the calculated forces. Other factors that contribute to 

large uplift forces include building width, eave 

height, roof angle, and overhang dimension. 

Additionally, the Galveston study concluded that the wind load provisions of the building code 

current at the time of investigation failed to meet the then current criteria of ASCE 7-88. The 

study further concluded that houses constructed since the adoption of the NFIP in 1971 utilizing 

flood-resistant construction and BFE elevations should perform to NFIP expectations; however, 

the practice of installing non-breakaway walls below the BFE in Zones V and Coastal A Zones were 

in violation of the NFIP and jeopardized the houses’ structural resistance to flood loads. 

2.2.4.1 Ike MAT Observations of Houses in the 1990 Galveston Study

The MAT chose to investigate 12 of the 31 houses included in the 1990 Galveston study located 

nearest the coastline and not protected by the seawall. Eleven of these houses were still standing after Hurricane Ike, but suffered varying degrees of damage (Figure 2-5). Number 2276, 

located on the Gulf side of Bermuda Drive, had been washed away by the storm. Number 3289, 

located in Indian Beach in a Zone V, is approximately 200 feet from the Gulf (Figure 2-6). This 

house had been under construction during the preparation of the Galveston study, thereby allowing the investigators to survey the building construction and connections. The Galveston 

study reported deficiencies for this house, including non-breakaway elements below the BFE 

and a roof uplift resistance greater than the local building code, but less than ASCE requirements. The MAT observed that the first floor was 2 feet above the BFE (17 feet) with significant 

pilings (12-inch by 12-inch) to girder connections and hurricane clips; however, many clips were 

corroded and broken (Figure 2-6 inset), as would be expected in this location. Refer to NFIP 

Technical Bulletin 8-96, Corrosion Protection for Metal Connectors in Coastal Areas (August 1996). 

PRE-FIRM AND POST-FIRM 

BUILDINGS 

For insurance rating purposes, a pre-FIRM 

building was constructed or substantially improved on or before December 31, 

1974, or before the effective date of the 

initial FIRM of a community, whichever is 

later. Most pre-FIRM buildings were constructed without taking the flood hazard 

into account.

A post-FIRM building was constructed or 

substantially improved after December 31, 

1974, or after the effective date of the initial 

FIRM, whichever is later. For a community 

that participated in the NFIP when its initial 

FIRM was issued, post-FIRM buildings are 

the same as new construction and must 

meet the NFIP’s minimum floodplain management standards.
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 2-23

FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS 2

During Hurricane Ike, the house suffered substantial wind damage to the asphalt shingles, vinyl 

siding, and soffits. The Galveston study identified the lack of shuttering for the house openings 

as a weakness. At the time of Hurricane Ike, the house openings were fully shuttered.

Number 3083, constructed in 1983, is located in Zone A in Point San Luis on a canal that opens 

to the West Bay (Figure 2-7). According to the Galveston study, this house’s identified weaknesses 

included overhangs greater than 4 feet, pile spacing greater than 12 feet, and walls or enclosures 

below the BFE that were not of breakaway construction. During Ike, the house was inundated by 

approximately 8 feet of water with waves that destroyed the majority of the first floor walls. 

Number 2480 is located on the West Bay in Zone A in Jamaica Beach with a Category C wind 

exposure (Figure 2-8). The Galveston study identifies the hurricane clips and bolted structural connections as strengths and the non-breakaway wall structures as a primary weakness. The 

house experienced both wind and flood damage during Hurricane Ike. Wind damaged vinyl 

siding and roof shingles on the north and west exposure of the house, an indicator of “backside” 

(north-to-south) winds. Flooding and waves undermined the concrete paving below the house 

and tore out ceilings, stairs, and wall structures below the first floor (Figure 2-9). 

Figure 2-6. 

Indian Beach house, 

post-Ike (number 3289 in 

1990 Galveston study)

Corroded and broken 

hurricane clips

Bolted piling and girder 

connection
2-24 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

2 FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS

Figure 2-7. 

Point San Luis house 

(number 3083 in 1990 

Galveston study)

Figure 2-8. 

Jamaica Beach house 

on the West Bay with 

“backside” wind damage 

(number 2480 in 1990 

Galveston study)
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 2-25

FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS 2

Figure 2-9. 

First floor walls removed 

and floor slab undermined 

by flooding and waves at 

this Jamaica Beach house 

(number 2480 in 1990 

Galveston study)

2.2.4.2 MAT Summary of Findings Regarding the Galveston Study 

The Galveston study concludes that the wind load provisions of the building code current at the 

time of investigation failed to meet the then current provisions of ASCE 7-88. The study further 

concluded that houses constructed since the adoption of the NFIP in 1971 utilizing flood-resistant construction and BFE elevations should perform to NFIP expectations; however, the 

practice of installing non-breakaway walls below the BFE in Zones V and Coastal A Zones were 

in violation of the NFIP and jeopardized the houses’ structural resistance to flood loads. The 

Galveston study rated each house for wind and water resistance based upon the collected data. 

The Galveston study assigned ratings to each house regarding performance for wind resistance 

and flood/wave resistance. The average rating in the study for the 12 houses sampled by the MAT 

was an “expected Poor Performance for wind resistance and a Good Performance for resistance to 

flood and wave loads.” Hurricane Ike was not a design wind speed event and wind damage to the 

houses was relegated to loss of asphalt shingles, siding, and soffit materials; therefore, a reasonable 

comparison of the Galveston study wind expectations could not be measured. 

Of the 12 houses visited by the MAT, Numbers 3289 and 2276 were the only houses located 

in Zone V. Number 3289 lost non-breakaway walls and Number 2276 was washed away by the 

storm. The other 10 houses were Zone A units with first floors located at or above the BFE. Four 

of these houses were slabs-on-grade and experienced flooding, while the other six houses were 

elevated and experienced breakaway and non-breakaway wall damage below the BFE, along 

with the loss of garage doors and ceiling finishes. The MAT’s observations of the resistance 

of the sampled houses to flood and wave loads indicate a “Poor Rating” in comparison to the 

Galveston study’s “Expected Good Performance.”
2-26 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

2 FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS

2.3 Texas Windstorm Program 

Hurricanes periodically strike the Texas Gulf coast. The City of Galveston was flattened in 1900 

by the Great Galveston Hurricane, the deadliest ever recorded in the State, killing approximately 8,000 people. Another massive storm, Hurricane Carla, killed 43 people and caused 

approximately $2 billion in property damage (in 2009 dollars) when it came ashore near Galveston in August of 1961. Hail storms, tornadoes, and floods subject other parts of the State to 

catastrophe, but only hurricanes have caused levels of devastation that demanded action by 

the State legislature. Because of the level of devastation caused along the Texas coast by previous hurricanes and prompted by Hurricane Celia (which caused significant damage to coastal 

areas near Corpus Christi in 1970), the TCPIA—a “Cat Pool” of insurers—was created by the 

Texas Legislature in 1971. The Cat Pool was renamed the Texas Windstorm Insurance Association (TWIA) in 1997. All insurers that write property insurance in Texas are required to become 

members of TWIA. Excess funds collected from premiums and investments are deposited in the 

Texas Catastrophe Reserve Trust Fund (CRTF) to pay for excess losses. According to a report on 

the TWIA, prepared by the Texas Department of Insurance (TDI) in October 2008, the current 

balance of the CRTF is zero as a result of losses from Hurricanes Rita (2005), Dolly (2008), and 

Ike (2008) (Insurance, 2008). 

TWIA operates under the authority of Chapter 2210 of the Texas Insurance Code. TWIA is a 

pool intended to serve as an “insurer of last resort” for individuals needing windstorm and hail 

insurance on buildings that are located in the first tier of coastal counties along the 367-mile 

Texas Gulf Coast; see Table 2-4 and Section 2.3.3. 

Table 2-4. Texas Counties covered by TWIA

Aransas Brazoria Calhoun

Cameron Chambers Galveston

Jefferson Kenedy Kleberg

Matagorda Nueces Refugio

San Patricio Willacy

Along with those counties indicated, TWIA also provides windstorm and hail coverage in certain specifically designated communities 

in Harris County that are east of State Highway 146. These communities include Pasadena, Morgan’s Point, Shoreacres, Seabrook, 

and La Porte.

2.3.1 Texas Department of Insurance

When the TCPIA was established in 1971, the Texas Legislature adopted the TCPIA Building 

Code for Windstorm Resistant Construction, which was based on the wind load provisions of 

the 1971 SBC. The damage caused by Hurricane Alicia in 1983 revealed that applicable building codes were not being enforced. As a result, the Windstorm Inspection Program at the TDI 

was created by the Texas Legislature, effective January 1, 1988. The TDI was charged with the 

following responsibilities:

n Certify to TWIA that buildings are constructed to the adopted windstorm code and 

therefore insurable against windstorm and hail losses
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 2-27

FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS 2

n Provide inspection services and process windstorm forms

n Though not part of the original charge, but as an integral part of the windstorm program, 

evaluate and list building products for compliance with the building specifications adopted 

by the TDI 

2.3.2 Basic Tenets of the Texas Windstorm Code

In 1989, the TDI began using the Windstorm Resistant Construction Guide, which was based 

on the SBC, as amended May 8, 1973, in addition to using the 1971 TCPIA Building Code for 

Windstorm Resistant Construction. In 1998, the TDI began using the TWIA (formerly TCPIA) 

Building Code for Windstorm Resistant Construction, which was updated to be based on ASCE 

7-93. In 2003, the TDI adopted the 2000 IRC and the 2000 IBC. This was followed by the adoption of the 2003 IRC and 2003 IBC in 2005, and most recently, the adoption of the 2006 IRC 

and 2006 IBC in 2008. 

Since 1998, the first tier counties, referred to as Designated Catastrophe areas, have been divided into three zones, referred to as Inland (II), Inland (I), and Seaward, by the TDI. The 

delineation between Inland (II) and Inland (I) is primarily roadways, city limits, and county 

lines. The delineation between Inland (I) and Seaward is the Intracoastal Waterway. The TDI 

also adopts wind speed requirements for each of the three zones. Figure 2-10 illustrates the 

three zones, as well as the current wind speed requirements adopted for each zone. The TDI 

has adopted amendments, called Texas Revisions, for each edition of the IRC and the IBC that 

have been adopted by the TDI. The Texas Revisions to the 2006 IRC and 2006 IBC include the 

following:

n Defines requirements for windborne debris protection as follows:

n Inland (II) – no protection required

n Inland (I) – all glazed openings to be protected

n Seaward – all exterior openings (windows, doors, skylights, and garage doors) to be 

protected

n In accordance with IRC Section R301, Design Criteria, and IBC Section 1609, Wind Loads, 

the provisions of the IBHS Guidelines for Hurricane Resistant Residential Construction (IBHS, 

2005) were added as an option for the designer and builder.

n Regarding asphalt roof shingles, in 

accordance with Sections R905.2, 

Requirements for Roof Coverings, 

of the 2006 IRC and Section 1504, 

Performance Requirements, of the 2006 

IBC, the TDI allows for shingles that 

have passed the ASTM D 3161, Standard 

Test Method for Wind-Resistance of Asphalt 

Shingles, Class F to be installed on roofs 

NOTE

For more information about the Texas 

Department of Insurance, visit http://www.

tdi.state.tx.us/wind/.
2-28 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

2 FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS

located in the Inland (II), the Inland (I), and the Seaward zones. In addition, the TDI 

permits the use of asphalt shingles that have passed ASTM D 7158, Standard Test Method 

for Wind Resistance of Sealed Asphalt Shingles, Class H to be installed in the Inland (I) 

and the Seaward zones. The TDI maintains a list of asphalt shingle products that have 

passed these criteria on their Windstorm Program Web.6

n The TDI requires building products to be tested to and comply with the test standards 

and criteria specified in the IRC, the IBC, and the Texas Revisions. Products that meet 

these criteria are evaluated by the TDI and listed on their Windstorm Program Web 

site. The TDI also evaluates and lists some types of building products that have passed 

test criteria used by Dade County, FL.

 6 www.tdi.state.tx.us/wind/geninfo.html

Figure 2-10. Texas Windstorm Designated Catastrophe Areas 

Source: http://www.tdi.state.tx.us/wind
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 2-29

FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS 2

2.3.3 Texas Windstorm Program – Insights and Opinions

The TDI Windstorm Program has evolved from using prescriptive codes and construction criteria with minimal requirements for high wind construction to adopting nationally recognized 

codes, such as the IRC and IBC. Properties that are constructed in accordance with the building 

specifications adopted by the TDI are eligible for insurability against wind hazards. However, 

numerous challenges continue for the windstorm program to remain solvent and for buildings 

to reliably resist hurricane wind forces. Some of these challenges and concerns include:

n TWIA losses in excess of a certain threshold will negatively impact the general revenue 

of the State of Texas. Numerous proposals are currently before the State Legislature to 

address this problem.

n The windborne debris criteria adopted by TDI address the opening protection for 

residences in the Seaward and Inland I zones, 130 mph and 120 mph wind zones, 

respectively. Ike’s winds were less than design levels, and therefore windborne debris was 

basically relegated to flying asphalt shingles, roof aggregate, and wall cladding materials. 

However, MAT observations from other hurricane events have found that windborne 

debris frequently perforates windows, doors, garage doors, as well as the building envelope 

(walls and roof), thereby allowing the entrance of water that damages home finishes 

and contents. Furthermore, debris impacts on large openings can allow wind to enter 

the home, thereby producing internal pressurization failures. The MAT observed that 

some homeowners shuttered the windward facing seaward side of their home and left the 

leeward side unprotected. The TDI should consider adopting windborne debris protection 

for all zones in the Designated Catastrophe Area, including the Inland II zone (110 mph), 

in accordance with the ASCE 7-05/IRC 2003 guidelines that require opening protection 

within 1 mile of the coastal mean high water line where the basic wind speed is equal to or 

greater than 110 mph. Glazing or opening protection should be compliant with ASTM E 

1886 and ASTM E 1996 as the impact testing criteria. This opening protection should be 

provided for all sides of the home, irrespective of the predominant wind direction or the 

expected direction of threat.

n Although Hurricane Ike was not a design wind event, significant losses of asphalt shingles 

(which were the predominate type of residential roof covering in the areas impacted by 

Hurricane Ike) were observed by the MAT (see Section 3.2.1.1). Asphalt shingles are 

affordable and available for use in areas with design wind speeds of 90, 120, and 150 

mph. When asphalt shingles are used, TDI should consider requiring the use of shingles 

complying with ASTM D 7158 Class G shingles in Inland (I) and Inland (II) zones, and 

Class H shingles in the Seaward zone. 
2-30 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

2 FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS

2.4 Enhanced Code Construction 

Several terms have been used to describe construction that exceeds minimum building code requirements, with two of the more common terms being “Code-Plus” and “Fortified.” 

n The Federal Alliance for Safe Homes (FLASH), Blueprint for SafetyTM program, has 

published a Contractors Field Manual, whose glossary7 defines “Code-Plus” as: “Additional 

measures are taken to build to higher standards or loads than the minimum required by 

code requirements. This adds strength and protection to the building” (FLASH, 2002).

n The IBHS has developed a Fortified . . . for safer living® program that specifies design, 

construction, and landscaping guidelines to increase a new house’s resistance to natural 

catastrophes, including hurricanes. After completing certain documentation, verification, 

and inspection steps, a builder is permitted to advertise a house as a “Fortified” house 

(IBHS, 2008).8

n Many FEMA documents, such as FEMA 55, Coastal Construction Manual: Principles and 

Practices of Planning, Siting, Designing, Constructing, and Maintaining Residential Buildings 

in Coastal Areas (June 2000) and FEMA 499, Home Builders Guide to Coastal Construction 

Technical Fact Sheet Series (August 2005), recommend best practices for design and 

construction that exceed minimum requirements of the NFIP and/or building code. These 

best practices include elevating a house to an elevation higher than the FIRM specifies (this 

practice is called “adding freeboard”); using an open foundation where a solid foundation 

may be permitted; and using different, additional, or stronger building components than 

the code calls for.

This Hurricane Ike MAT report refers to the above types of construction collectively as enhanced 

code construction. The exact meaning may vary geographically, because different States and communities have adopted and amended different building codes, or different editions of those codes, 

and thus have different minimum design and construction requirements. 

One of the most important aspects of enhanced code construction for consumers and communities to recognize is that the mere designation or advertising of a building as being enhanced 

code construction does not necessarily mean the building will survive a hurricane or other 

severe event without damage. The MAT observed some enhanced code houses in Galveston 

County, TX, with flaws that led to building damage during Hurricane Ike, sometimes under less 

than design conditions. 

Consumers and communities should also keep in mind that the criteria used to designate enhanced code construction evolve over time, and a house that satisfied enhanced code criteria 

at one point in time (and was truthfully claimed to be enhanced code construction) may not 

meet today’s criteria. 

7 http://www.blueprintforsafety.org/glossary.php

8 See the Builder’s Guide at http://disastersafety.org/text.asp?id=builder_guide for more details
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 2-31

FLOODPLAIN MANAGEMENT REGULATIONS, BUILDING CODES, AND STANDARDS 2

One important aspect of enhanced code construction in coastal areas is designing and constructing buildings to withstand flood levels above the BFE. Accomplishing this will require the 

addition of freeboard (see Section 7.1.1), strengthening foundations, and using flood damageresistant materials above the lowest floor. A Hurricane Ike Recovery Advisory, Designing for Flood 

Levels Above the BFE (see Appendix D), is available to assist communities, design professionals, 

builders, and consumers.

HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 3-1

PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly 3

Performance of Residential 

Buildings (Flood and Wind), 

One- to Two-Family and 

Multi-Family

Assessing the structural and building envelope performance of 

residential buildings was one of the main goals of the MAT.

3.1 Structural Performance

Assessing the structural and building envelope performance of residential buildings was one of 

the main goals of the MAT (the other being the assessment of critical facility performance—see 

Chapter 4). Making these assessments required location-specific information, gathered prior 

to and during the MAT’s field investigations, and knowledge of the flood and wind loads and 

3Performance of Residential 

Buildings (Flood and Wind), 

Chris Jones 

Larry Tanner 

David Johnston

Dave Low

Mark Matulik

Tom Smith

Wallace Wilson
3-2 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

conditions to which the buildings were exposed during Hurricane Ike. In a few cases, additional data were gathered after field work was completed, but in most cases building performance 

judgments were based on information available to the MAT while in the field. Although the 

MAT believes its assessments of buildings described in this chapter are correct, statements made 

herein are not intended to represent final judgments as to the cause of damage to individual 

buildings—the MAT recognizes that further investigation by others may refine or alter judgments made by the MAT. Nevertheless, general damage patterns and trends observed by the 

MAT are valid and can be used as the basis for recommendations to improve residential design 

and construction.

3.1.1 Foundation Performance 

Foundations in coastal areas must be able to perform several functions:

n Elevate the building above the surge and wave crest level 

n Remain intact and functional despite scour and erosion effects

n Provide a continuous load path from the elevated building to the ground, and resist all 

vertical and lateral loads transferred from the elevated building to the foundation

n Resist flood loads—including storm surge, wave, and floodborne debris impacts—acting on 

the foundation and on any below-flood level obstructions that do not break away

Failure to perform any of these functions can result in building damage or loss. The MAT observed foundations that performed well (Figure 3-1), and foundations that failed to satisfy one 

or more of the requirements listed above. 

Failures of the most common type of foundation observed by the MAT—the open (e.g., pile or 

column) foundation—were usually associated with one of two factors: insufficient embedment 

into the ground, or breakage of the piles or columns. 

Embedment Failures. Embedment failures occur where a foundation is not deep enough in the 

ground to resist wind and flood loads pushing on the structure; a leaning foundation or overturned building results (Figure 3-2). Scour and erosion can exacerbate this mode of failure by 

reducing embedment. 

Pile and Column Breakage. Pile and column breakage occur where the strength of the piles or columns is inadequate to resist the bending moments or shear forces caused by the flood and wind 

loads acting on the structure (Figures 3-3 and 3-4). Scour and erosion contribute to this mode 

of failure by increasing the un-braced pile/column length and by increasing the bending moments in the pile/column. 

The methods used to secure an elevated building to the top of the foundation can affect the 

overall foundation strength. Connections at the tops of the piles or columns that do not provide 

fixity (i.e., resistance to rotation) allow greater stresses to develop in the piles or columns than 

would develop with connections that rigidly tie the structural elements together. 
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 3-3

Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family 3

In most buildings the MAT evaluated, timber construction was used and the tops of the piles or 

columns were connected to the elevated buildings with bolted connections (Figure 3-5). This 

type of connection provides limited fixity; weakness in this type of connection can be overcome 

in some instances through the use of larger piles or columns and other design details that help 

to stiffen the foundation.

Figure 3-1. 

Louisiana house 

sufficiently elevated on a 

foundation that withstood 

Ike flood loads

Figure 3-2. 

A house on timber piles 

was pushed over by wind 

and flood loads and the 

load path failed at the 

connection between the 

floor beam and the piles. 

Embedment and elevation 

were also insufficient at 

this Bolivar Peninsula, TX, 

site.
3-4 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

Figure 3-3. 

Broken timber piles 

(Galveston Island, TX)

Figure 3-4. 

This concrete column 

failed due to lateral loads. 

Note limited overlap of 

reinforcing steel at the 

bottom of the column.
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 3-5

PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly 3

3.1.1.1 Foundation Function 1: Elevate the Building

Elevation is one of the most important keys to a successful coastal building. The MAT observed 

many residential buildings along the Gulf shoreline that were elevated above the effects of Ike’s 

storm surge and waves, and sustained no significant damage; on the other hand, nearby buildings that were at lower elevations were heavily damaged or destroyed (Figure 3-6).

Figure 3-5. 

Typical bolted connection 

between wood columns 

and wood beams

Figure 3-6. 

Unlike the older and 

lower house on the 

right, the Zone V house 

on the left was elevated 

approximately 5 feet 

above the 16-foot National 

Geodetic Vertical Datum 

(NGVD) BFE and sustained 

no structural damage due 

to flooding (Crystal Beach, 

TX)
3-6 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

3 PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly

It was difficult to obtain HWMs for flood levels 

on Bolivar Peninsula due to the magnitude of 

the destruction there. However, the MAT was 

able to supplement high water mark data collected by government agencies (see Section 1.2.3) 

with wave damage data in elevated houses that 

remained standing after Ike. For instance, houses such as the one shown in Figure 3-6 indicate that the wave crest elevation at that location was 

below the bottom of the elevated floor system (due to the fact that the floor system was intact). 

Damage such as that shown in Figure 3-7, where the shore-parallel floor joists were displaced 

landward, indicates the onset of wave damage to an elevated floor system. By carefully examining several such houses and by acquiring the corresponding lowest floor elevations from NFIP 

Elevation Certificates, the MAT concludes that the wave crest elevation reached approximately 

18 to 20 feet NGVD, an elevation approximately 2 to 4 feet higher than the BFEs at these particular houses. Although it is possible that the wave crest reached higher elevations relative to the 

BFE, it is unlikely based on the lack of wave damage at some houses that were approximately 5 

feet above the BFE (waves apparently passed beneath those elevated houses).

Figure 3-7. 

The landward 

displacement of shoreparallel floor joists 

indicates the onset of 

wave damage to an 

elevated floor system 

(Bolivar Peninsula, TX)

The MAT also observed many bay shoreline and inland examples that demonstrate the importance of elevation. Houses situated at higher elevations, whether because of elevated foundations 

or because of being sited on high ground, sustained little or no damage, while adjacent houses 

with lower elevations were damaged or destroyed. In many cases, undamaged bay-front houses 

were elevated above the surge and wave elevation on pile foundations. Figure 3-8 shows a house 

elevated above the BFE and Ike wave effects that suffered no significant damage due to flooding. However, the nearby at-grade house shown in the inset was heavily damaged. On some 

bay-front shorelines (or inland areas) where storm wave heights were smaller and where erosion 

did not threaten a house, siting on natural high ground or fill provided the required elevation 

and support for the house (Figure 3-9).

The MAT’s observations of wave damage 

and analysis of building elevation data 

indicate that the wave crest elevation on 

much of the Bolivar Peninsula reached 

approximately 2 to 5 feet above the BFE.
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 3-7

PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly 3

The MAT observed many houses in more inland locations that were not elevated high enough 

to avoid Ike flooding, and were apparently subject to surge inundation, low-velocity storm surge 

flow, and, in some cases, minor wave action. These houses sustained varying degrees of flood 

damage depending on site-specific flood depths, flood loads, and construction details. Some 

Figure 3-8. 

This elevated house (Zone 

V, BFE = 15 feet) suffered 

no significant damage due 

to flooding. The nearby 

at-grade house in the 

background, shown in 

the inset, was heavily 

damaged (Baytown, TX).

Figure 3-9. 

Adjacent houses south of Baytown, TX. The house on the left (Zone X) was above the surge and wave runup level 

and sustained no flood damage. The house on the right (Zone A, BFE = 13 feet) was at a lower elevation and was 

largely destroyed by surge, waves, and floating debris.
3-8 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

3 PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly

were inundated by several feet of flooding, as they had been during Hurricane Rita in 2005. The 

house shown in Figure 3-10 was not subject to wave action during Ike and suffered no apparent 

structural damage. However, flood damage to contents and finishings were likely severe. Other 

houses sustained significant structural damage due to storm surge flow (Figure 3-11). Some 

floated or were washed off their foundations (Figure 3-12).

Figure 3-10. 

The Ike flood level reached 

approximately 3 feet 

above the floor slab (1 

foot above the 6-foot 

BFE) of this Zone A house 

(see inset), which was 

reported to have been 

similarly inundated during 

Hurricane Rita. The MAT 

was told that the house 

will be elevated (Lake 

Charles, LA).

Figure 3-11. 

This house sustained 

significant structural 

damage due to storm 

surge and small waves 

above the 9-foot BFE in 

Zone A (Bridge City, TX). 

Note flood debris line on 

the roof.
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 3-9

Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family 3

The tallest residential foundations the MAT 

observed were at Fortified... for safer living®

houses (see text box and Section 2.4) on Bolivar Peninsula. The houses are elevated with 

their lowest floor at approximately 27 feet 

NGVD (21 feet above the ground), 10 feet 

above the BFE (Figure 3-13). These foundations are reinforced, cast-in-place concrete 

columns connected to concrete slabs and 

drilled concrete shafts (extending 10 feet below grade). Ten of the 13 houses survived Ike, 

and three were destroyed. 

The houses had substantial timber decks connected to the columns at or just above the BFE, 

approximately mid-way between the ground and the elevated houses. Although not designed 

as breakaway decks, the decks broke away during Ike, probably a result of both wave and floodborne debris effects. The deck failures damaged some of the concrete columns where the decks 

were connected (Figure 3-14). 

The concrete columns left standing between 

the slabs and the (destroyed) elevated decks 

were observed to have a series of horizontal 

cracks in the columns (Figure 3-15). These 

cracks likely resulted from the columns bending in response to a combination of wind loads 

on the elevated houses, flood loads (waves, 

currents, debris) on the columns, and transfer 

of flood loads from the decks to the columns.

Figure 3-12. 

This house floated off 

its foundation due to 

insufficient elevation and 

inadequate connections 

between the foundation 

and the house (Golden 

Meadow, LA) 

WARNING

Elevation alone is not adequate to ensure a 

building will perform well during a high wind 

and flood event. A building must be elevated 

on a well-designed and constructed foundation. Some of the tallest foundations the Ike 

MAT observed either failed or were in danger 

of failing.

Fortified... for safer living®

The Fortified... for safer living® designation 

is from the Institute for Business and Home 

Safety. The “Fortified®” program specifies design and construction guidelines to increase 

a house’s resistance to natural disasters 

such as hurricanes. For more information:

www.disastersafety.org/text.asp?id=fortified.
3-10 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

3 PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly

Figure 3-13. 

Looking toward the Gulf, 

past Zone V houses on 

tall concrete column 

foundations (with the lowest 

floor 10 feet above the 17-

foot BFE). Four of the five 

tall houses shown in this 

photograph survived Ike (red 

circle indicates destroyed 

house). The red arrow points 

to exposed geotextile tube 

(under former dune). Note 

other destroyed houses (not 

on tall foundations) seaward 

of the highway (Bolivar 

Peninsula, TX).

Figure 3-14. 

Ground-level view of 

elevated houses with inset 

showing typical column 

damage where the timber 

deck broke away (Bolivar 

Peninsula, TX)
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 3-11

PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly 3

3.1.1.2 Foundation Function 2: Resist Scour and Erosion

Residential building performance in coastal areas often depends on the capability of the building foundation to accommodate a lowering of the ground elevation and loss of soil support. 

The lowering of the ground is often accompanied by high winds, storm surge, large waves, and 

debris propelled by wind or water, which further magnify any adverse effects of soil loss. 

For foundation design purposes, it is important to distinguish the nature and extent of soil loss 

expected around a building, since these can affect the stillwater flood depth and the magnitude 

of the flood conditions at the site (see erosion and scour text box on next page).

The MAT observed significant levels of erosion and scour near buildings situated along the 

Gulf of Mexico. Erosion was widespread along the Gulf of Mexico shoreline of Follets Island, 

Figure 3-15. 

Concrete column showing cracking that 

was likely caused by extreme column 

bending stresses due to lateral loads 

on the elevated house and foundation 

(Bolivar Peninsula, TX)
3-12 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

Galveston Island, and Bolivar Peninsula, TX, and portions of southwest Louisiana. Scour was 

particularly evident around building foundations on Bolivar Peninsula and at Holly Beach 

(Cameron Parish, LA). The MAT believes that erosion and scour were among the major contributors to structural failure of buildings close to the Gulf shoreline. Significant erosion and 

scour were not observed by the MAT along the bay shorelines, although there may have been 

some locations where such erosion and scour occurred.

EROSION AND SCOUR

Erosion is a lowering of the ground surface over a large area, usually brought on by a coastal storm or 

long-term shoreline recession. Erosion increases the unbraced length of vertical foundation elements 

and increases the stillwater depth at the building, allowing larger waves to reach the foundation.

Scour is a localized loss of soil immediately around an object or obstruction. Scour also increases the 

unbraced length of vertical foundation elements, but does not act to increase the stillwater flood depth 

across which waves propagate (thus, scour can be ignored for wave height calculation purposes). 

Walls, columns, pilings, pile caps, footings, slabs, and other objects found under a coastal building can 

contribute to localized scour.

Depending on the building location, soil characteristics, and flood conditions, a building may be subject 

to either coastal erosion or scour, or both. Refer to Hurricane Ike Recovery Advisory on Erosion, Scour 

and Foundation Design (Appendix D) for additional information.

A preliminary review of pre- and post-Ike aerial photographs suggests that between 100 and 

200 feet of dunes and vegetation were lost during Ike along much of the Gulf shoreline (see 

Figure 3-16).

This loss occurred in areas with natural dunes and in areas where previously eroded dunes 

had been rebuilt and reinforced with geotextile tubes (see Figures 3-13 and 3-17). As of 2003, 

approximately 7.6 miles of geotextile tube dune reinforcement had been installed along the 

Texas shoreline, mostly along the Bolivar Peninsula and western Galveston Island shorelines 

(Gibeaut et al., 2003). Virtually all of these tubes were uncovered by Ike, and many were 

destroyed.
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 3-13

Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family 3

The Ike MAT noted that the amount of scour around pile foundations was far greater than that 

observed during previous post-storm investigations, both in terms of frequency of occurrence 

and depth of scour. Most of the scour was observed at foundations with concrete slabs at ground 

level, but this is likely due to the prevalence of this type of construction; significant scour was 

also observed around some pile foundations before the slabs had been constructed. Significant 

scour (several feet deep, tens of feet in diameter) was observed after Ike at hundreds of the 

buildings that were still standing near the Gulf shoreline. 

Figure 3-16. 

Pre- and post-Ike aerial 

photographs of the east 

end of Galveston Island, 

TX, illustrating some of 

the most significant loss 

of dunes and vegetation 

during Ike 

Source: USGS, http://

coastal.er.usgs.gov/

hurricanes/ike/photocomparisons/galveston.html
3-14 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

3 PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly

Figures 3-18 and 3-19 show buildings at Holly Beach, LA, both of which sustained significant 

scour around foundations. Of the approximately 20 pile-elevated houses in existence at Holly 

Beach prior to Hurricane Ike, nearly half experienced significant foundation scour (virtually all 

of buildings at Holly Beach were destroyed by 

Hurricane Rita in 2005, and the houses observed 

by the Ike MAT had been built since 2005).

Figure 3-18. 

Foundation scour 

observed at Holly 

Beach, LA

Figure 3-17. 

Exposed geotextile tubes 

formerly covered by sand 

and dune vegetation. 

Note erosion behind the 

tubes and under Zone V 

(BFE = 18 feet) buildings 

(yellow arrow at left).

The amount of scour around pile foundations observed by the Ike MAT far exceeded 

what current design guidance predicts.
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 3-15

Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family 3

Figure 3-20 shows a case of extreme foundation scour at a house on Bolivar Peninsula. The 

scour depression shown was reported by a local contractor to have been as much as 10 feet deep. 

The house was able to withstand the scour and the wind and flood loads acting on the structure, 

but lack of soil support allowed the bottoms of some of the piles supporting the deck on the 

right side of the house to be shifted toward the left.

Figure 3-20. 

Foundation scour was 

reported to be 10 feet 

deep—note the bottoms 

of the piles on the right 

side of building that have 

been pushed toward 

the building (Bolivar 

Peninsula, TX; Zone V)

Figure 3-19. 

Foundation scour 

observed at Holly Beach, 

LA (Zone V, ABFE = 16 

feet)
3-16 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

Figure 3-21. 

Failure of a timber pile 

foundation undermined 

by scour and erosion. 

Inset shows close-up 

of concrete slab failure 

and rotation of some 

of the foundation piles 

(Galveston Island, TX; 

Zone V).

In some cases, pile foundations subject to erosion and/or scour were not embedded deeply 

enough to resist the loads and conditions that were present during Ike. Figure 3-21 shows such 

a case where a pile foundation shifted under an elevated house. Scour and erosion contributed 

to the failure. The presence of the attached, but broken, concrete slab could also have contributed to the foundation failure by reducing the lateral support formerly provided by the intact 

slab, and by causing eccentric loading of the piles (see Section 3.3.3).

One other aspect of scour was noted by the MAT—linear scour features that result in the loss of 

soil around or under buildings when storm surge flow is channeled or directed across a building site. This process usually takes place where storm surge flow is constrained between large 

buildings or gaps in shore protection, or when storm surge return flow to the sea follows paths 

of least resistance, such as along canals and roads (Figure 3-22). Some of the many buildings lost 

during Ike were likely lost as a result of this process.
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 3-17

PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly 3

Figure 3-22. 

Linear scour features 

tend to align with canals 

and roads as storm 

surge returns to the Gulf. 

Houses such as this one 

were fortunate not to 

be undermined and lost 

during Ike, as many homes 

undoubtedly were (Bolivar 

Peninsula, TX).

3.1.1.3 Foundation Function 3: Provide a Continuous Load Path to the Ground

Loads acting on a building follow many paths through the building and must eventually be resisted by the ground, or the building will fail. Loads accumulate as they are routed through key 

connections in a building (connections between members are usually the weak links in a load 

path). Load paths must be continuous, from the top of the building, through the foundation, 

and into the ground; failed or missed connections cause the loads to be rerouted through unintended load paths, potentially overloading those paths and resulting in structural failure. A 

graphic illustrating vertical and horizontal load paths from an elevated building to the foundation and into the ground is shown in Figure 3-23.

Connections between structural members are often the weak point in a load path, and the MAT 

observed many load path failures at the floor system-pile connection. The MAT also observed 

instances where this connection was adequate to prevent structural failure during Ike. Figure 

3-24 shows an example of a wood-frame house elevated on concrete columns. The house survived with no structural damage even though the owner reported a flood level above the lowest 

floor. The attachment of the timber floor beams to the concrete columns provided load path 

continuity and prevented the house from floating or washing off its foundation (Figure 3-25). 

Although this house survived Hurricane Ike, this type of connection only provides limited resistance to lateral loads and applied moments—had the house experienced a higher surge or 

stronger winds, it may not have survived. The MAT estimated the 3-second gust wind speed (Exposure C) during Ike was approximately 85 mph at this site, but if wind speeds or lateral flood 

loads had been higher, this house could have sustained structural damage.
3-18 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

Figure 3-23. 

Example load path through 

a pile foundation (note: 

some building components 

are not shown) 

Source: FEMA P-762, 

Local Officials

Guide FOR Coastal

Construction

Figure 3-24. 

This Bridge City, TX, house 

sustained no structural 

damage, despite the fact 

that the owner reported 

that Ike flood levels rose 

above the lowest floor
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 3-19

PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly 3

Figure 3-25. 

A 5

/8-inch diameter 

galvanized steel anchor 

bolt in red circle (with 

washer and nut, not 

visible in this photograph) 

provided connections 

between beam and 

column for the house 

shown in Figure 3-24. 

This does not appear to be 

an engineered connection.

Some designs rely on connections between columns and beams to provide fixity (resistance to 

rotation), particularly in commercial or multi-family buildings of concrete construction. Figure 

3-26 shows one such example—reinforcing steel that will extend into a concrete beam (under 

construction) and connect columns and beams. The cast-in-place concrete connection will provide resistance to rotation.

Figure 3-26. 

Reinforcing steel 

extending from the top of a 

concrete column (building 

under construction) 

(Galveston Island, TX)

The MAT noted instances of other types of foundation load path failures, including those at the 

point where a column attached to a pile cap, slab, or grade beam. Deterioration of timber piles 

contributed to load path failures in some foundations (Figure 3-27). The deterioration could have 

been the result of inadequate preservative treatment or poor design/construction practice. In other cases, deterioration was observed that did not result in foundation failure during Ike; however, 

such a weakened foundation would be more susceptible to failure in the future (Figure 3-28).
3-20 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

Figure 3-27. 

Deterioration in the wood 

piling likely contributed 

to the foundation failure 

(Bolivar Peninsula, TX)

The MAT also noted cases where houses survived Ike, but must not have been exposed to high 

winds or large flood loads; otherwise the lack of load path continuity would have resulted 

in foundation failure. The house shown in Figure 3-29 is resting on top of precast concrete 

piers, stacked concrete masonry units (CMUs), and shallow footing pads—the necessary 

structural connections are missing. This design will not provide a continuous load path from 

the elevated house to the ground, and does not comply with minimum NFIP or building 

code requirements. This foundation will likely fail if it is subject to high winds and/or waves, 

velocity flow, or scour. Additional discussion of load paths is provided in Section 3.1.2.3.

Figure 3-28. 

Deterioration in wood 

piling. The foundation did 

not fail during Ike, but it 

was weakened and will be 

more susceptible to failure 

in the future (Galveston 

Island, TX). 
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 3-21

PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly 3

Figure 3-29. 

House resting (i.e., with 

no structural connection) 

on top of precast concrete 

piers, stacked CMUs, and 

shallow footing pads (New 

Iberia, LA)

3.1.1.4 Foundation Function 4: Resist Flood Loads

Flood loads acting on a coastal building can include: 

n Hydrostatic loads (pressure from standing or slowly moving water). Vertical hydrostatic 

forces are known as buoyant forces, and cause objects to float, including houses that 

are poorly attached to their foundations. Lateral hydrostatic forces will not harm pile or 

column (open) foundations, but can cause damage to foundation walls and enclosure walls 

that do not have the flood openings required to allow inside and outside water levels to 

equalize. 

n Hydrodynamic loads (forces caused by fast-moving water, the up-rush of broken 

waves, etc.). Storm surge flowing past or around a foundation or building will lead to 

hydrodynamic loads. 

n Wave loads (caused by waves breaking on or striking a building foundation). Wave loads 

are high magnitude, short duration loads that can cause rapid destruction of inadequately 

elevated or constructed buildings. Hundreds of waves can strike a building during an 

episode of hurricane flooding. 

n Floodborne debris impacts (parts of broken structures striking a building, or becoming 

lodged in a building foundation and transferring other flood loads to the foundation). 

Large numbers of buildings destroyed by flood forces contributed to large quantities of 

floodborne debris, and undoubtedly led to additional building failures during Ike. 

Flood damages to residential buildings observed by the MAT were consistent with the nature 

and magnitudes of the flood loads described above. 
3-22 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

n In locations where waves were small and 

flood velocities were low, there was little 

damage to houses elevated above the flood 

level on NFIP-compliant foundations. 

Houses constructed at grade, or not elevated 

high enough above the ground to escape 

the flooding, were inundated and sometimes 

dislodged from their foundations.

n In locations where waves were larger, flow 

velocities were greater, and floodborne 

debris generation was significant. Houses 

not elevated high enough were severely 

damaged or destroyed. Houses elevated 

above the wave crest level were still 

subject to damage or destruction if their 

foundations could not withstand the flood 

loads and failed. 

The typical wave damage patterns described 

above are illustrated in Figure 3-30. Damage 

to properly designed and constructed elevated 

houses is generally minor until the waves reach 

the elevated floor system, at which point the 

damage increases dramatically with increasing 

water level and wave height. The importance of adding freeboard—elevating above the wave 

crest level—is apparent (see Section 3.1.3 and the Ike Recovery Advisory, Designing for Flood Levels above the BFE).

Figure 3-30. Idealized depth-damage relationship for an elevated building subject to waves 

Typical, low-rise residential buildings near 

the shoreline can be designed and constructed to resist wind loads, but must be 

elevated high enough on a pile or column 

(open) foundation to avoid flood loads. 

Wind pressures acting on walls of low-rise 

buildings are almost always less than 100 

pounds per square foot (psf), and these 

loads can be resisted easily by proper 

design and construction. However, fastmoving storm surge and floodborne debris 

can exert pressures several times higher than wind pressures against a building 

wall. Wave pressures against walls can 

reach several hundred, or in extreme cases, thousands of psf. 

Even lateral flood loads acting on pile 

or column foundations can reach 1,000 

pounds or more against each pile or column. These loads can be resisted, but only 

by properly designed and constructed open 

foundations. 
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 3-23

Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family 3

Wave effects and floodborne debris impacts 

were a major cause of building structural failure during Hurricane Ike, both on lands near 

the Gulf of Mexico and immediately adjacent to 

many bay-front shorelines. Damage was more severe and widespread along the Gulf shoreline, 

as would be expected, since the wave heights 

were larger there. Also, the loss of many buildings along the Gulf shoreline added greatly to 

the debris stream available to strike and damage 

other buildings farther inland. 

It is not always possible to separate damages 

caused by waves alone from that caused by floodborne debris, especially since the debris is carried 

by the surge and waves. However, the direct and 

indirect effects of waves should be considered 

one of the two most damaging aspects of coastal 

flooding for coastal residential buildings (erosion and scour being the other).

Figure 3-31 shows a comparison of pre- and post-Ike photographs for the Crystal Beach area of 

the Bolivar Peninsula. The Peninsula is the region where Hurricane Ike storm surge levels and 

wave heights appear to have reached maximums along the Gulf shoreline. Buildings along the 

Gulf shoreline of the Peninsula were likely subject to the greatest flood forces during Ike, and 

sustained the worst damage. Damage in this area has been compared to the Mississippi coast 

following Hurricane Katrina.

Figures 3-32 and 3-33 show examples of houses affected by waves and the inland penetration of 

large debris fields. The combination of waves and debris led to the destruction of many houses 

on Bolivar Peninsula.

An estimated 3,600 buildings, (approximately 61 percent of the pre-Ike buildings) 

on Bolivar Peninsula were destroyed by 

Hurricane Ike, and approximately 2,200 

(37 percent) more were damaged (Halff 

Associates, 2008). Much of the Peninsula 

was inundated by an estimated 6 to 10 

feet of stillwater, and experienced wave effects above that level—meaning that Ike 

flood levels exceeded the BFE for virtually all of the Peninsula. This would explain 

the widespread loss of elevated houses 

on the Peninsula, and the survival of only 

those houses elevated the highest, with 

deep foundations resistant to waves, debris, storm surge, erosion, and scour.
3-24 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

Figure 3-31. 

Pre- and post-Ike aerial 

photographs of the Crystal 

Beach area of Bolivar 

Peninsula, TX 

Source: USGS1

1 http://coastal.er.usgs.gov/hurricanes/ike/photo-comparisons/bolivar.html
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 3-25

Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family 3

Although flood levels and wave conditions were not as severe on Galveston Island as on the Bolivar Peninsula, many houses were also lost there, largely as a result of waves and erosion. Figure 

3-34 shows one example, approximately 3 miles west of the seawall, where two Gulf-front houses 

were lost.

Figure 3-32. 

Seaward side of Zone V 

house struck by waves. 

The deck, the elevated 

floor system, and the 

seaward walls were 

destroyed or heavily 

damaged (Bolivar 

Peninsula, TX).

Figure 3-33. 

Roofs, walls, and other 

parts of destroyed houses 

washed landward to and 

inland of this location, 

approximately 1⁄2 mile 

from the Gulf shoreline of 

Bolivar Peninsula, TX
3-26 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

3 PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly

Figures 3-35 and 3-36 show examples of Ike wave damage typical for Galveston Bay, where wave 

heights were less than those on the Gulf shoreline. These at-grade buildings were gutted or destroyed by storm surge, waves, and floodborne debris. In both cases, nearby buildings elevated 

on pile foundations survived, with damage only to breakaway walls and access stairs.

Figure 3-34. 

Broken piles beneath 

destroyed Gulf-front 

houses, Galveston Island, 

TX (west of the seawall)

Figure 3-35. 

Damage to at-grade house 

in Zone V likely caused by 

wave and surge along the 

northern Galveston Bay 

shoreline in Baytown, TX
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 3-27

Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family 3

3.1.2 Main Wind Force Resisting System

According to ASCE 7-05, the MWFRS is an assemblage of structural elements that provide support and stability for the overall structure. The MWFRS can be thought of as the portion of a 

building’s structural frame that collects wind loads from the building envelope and transfers 

those loads to the ground via the building’s foundation. Elements of the building envelope 

that do not qualify as a part of the MWFRS are identified as C&C. While some may consider the 

foundation to be part of the MWFRS, the following discussion will focus on that portion of the 

structural system above the foundation. 

3.1.2.1 High Winds 

High winds can originate from a number of events—tornadoes, hurricanes, extra-tropical cyclones, and other coastal storms. The most current design wind speeds are given by the national 

load standard, ASCE 7-05. Figure 3-37, taken from ASCE 7-05, shows the geographic distribution 

of design wind speeds for Gulf of Mexico and Atlantic Ocean portions of the United States.

Figure 3-36. 

Likely wave and debris 

damage to townhouse 

building along the 

western Galveston Bay 

in Seabrook, TX. The 

building was supported 

on shore-parallel masonry 

walls, and is landward of 

another building that was 

destroyed by Ike.
3-28 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

Figure 3-37. ASCE wind speed map (ASCE 7-05)

High winds are capable of imposing large lateral (horizontal) and uplift (vertical) forces on 

buildings (see Figure 3-38). Residential buildings can suffer extensive wind damage when they 

are improperly designed and constructed and when wind speeds exceed design levels. The damages shown in Figures 3-39, 3-40, and 3-41 exemplify poor design and construction, since Ike’s 

winds were less than design levels.

The effects of high winds on a building will depend on several factors:

n Maximum wind speeds, gustiness of the winds, wind directions, and duration of high winds

n Height of building above ground

n Exposure or shielding of the building (by topography, vegetation, or other buildings) 

relative to wind direction

n Topographic effects (hills and escarpments) that create wind speedup

n Strength of the structural frame, connections, and envelope (walls and roof)

n Shape of building and building components
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 3-29

PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly 3

n Number, size, location, and resistance to damage of openings (e.g., windows, doors, and vents)

n Presence and strength of shutters or opening protection

n Type, quantity, and velocity of windborne debris

Proper design and construction of residential structures, particularly those close to open water 

or near the coast, demand that every factor mentioned above be investigated and addressed 

carefully. Failure to do so may ultimately result in building damage or destruction by wind. 

Hurricane Ike winds removed the roof structure on the house shown in Figure 3-41. Hurricane 

straps could have been added, thereby greatly increasing the resistance to wind. Refer to IBHS 

2005 Standards for proper connection of roof structural elements.

Figure 3-38. 

Code-defined MWFRS 

wind loads on an elevated 

residential structure

SouRcE: FEMA 55

Figure 3-39. 

Galveston, TX, West End 

Beach house with roof 

structure removed by 

Hurricane Ike. 

The cause of the failure 

is unknown, but Ike wind 

speeds in this area were 

below design speeds 

(Hurricane Ike estimated 

wind speed in this area: 93 

mph, Exposure C).

Wind Direction
3-30 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

3.1.2.2 Combination of Loads – MWFRS and C&C

Some elements of low-rise buildings are considered to be part of the C&C or part of the MWFRS, 

depending upon the wind load being considered. Using the example of the exterior walls of a 

masonry building, the MWFRS provisions are used to determine the in-plane shear forces in the 

design of these masonry walls, and the C&C provisions are used to determine the out-of-plane 

design bending loads.

Figure 3-41. 

The roof structure was 

poorly connected to 

this house in Grand Isle 

(Jefferson Parish, LA) and 

was blown off by 50-mph 

Ike winds (Exposure B)

Figure 3-40. 

This West Bay, Galveston 

Island, TX, apartment 

experienced gable-end 

wind damage as a result 

of sheathing failure and 

poor connection of the 

brick veneer to the stud 

walls (Hurricane Ike 

estimated wind speed 

in this area: 90 mph, 

Exposure B)
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 3-31

PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly 3

The pressure (positive/inward or negative/outward suction) exerted by wind flowing over and 

around a building varies with time and location on the building. The highest pressures occur 

over small areas for a very short time in the regions of a building where the wind flow separation 

is quite significant (such as at corners of roofs and walls, ridges, hips, and overhangs). This flow 

separation can cause small vortices to form that can cause much higher pressures in small 

localized areas. These flow separation regions generally occur along the edges of the roof and 

corners of exterior walls (see Figures 3-42 and 3-43). Therefore, the design wind pressures 

for the design of the C&C element can be nearly three times the pressure used to design the 

structural framing of the building. Proper assessment of the design wind pressures is critical to 

developing the design of a building’s structural frame and the selection of appropriate exterior 

cladding.

Figure 3-42. 

Areas of roof covering 

loss (red arrows) indicate 

zones of higher wind 

pressure on a roof

Figure 3-43. 

Galveston, TX, West End 

Beach house with roof 

damage in high pressure 

zones (Hurricane Ike 

estimated wind speed 

in this area: 95 mph, 

Exposure C)
3-32 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

In addition to these external pressures, openings and the natural porosity of the building components contribute to internal pressures. As seen in Figure 3-44, internal pressures introduced 

by building openings are additive to (or subtractive from) the external pressures. The magnitude 

of the internal pressures depends on whether the building is “enclosed,” “partially enclosed,” or 

“open” as defined by ASCE 7-05. In hurricane-prone regions as defined by ASCE 7-05, in order 

for a building to be considered “enclosed” for design purposes, glazing must either be impactresistant or protected with shutters or other devices that are impact-resistant. This requirement 

also applies to indoor glazing and skylights. Refer to Section 3.2.4 for the discussion on windows 

and shutters and their performance in Hurricane Ike. As previously stated, Hurricane Ike was 

not a wind design event and therefore the MAT did not observe any notable examples of building failures resulting from internal pressurization.

Figure 3-44. 

Effect of wind on an enclosed building and a building with a wall opening producing a partially enclosed building 

by allowing internal pressurization of the structure

3.1.2.3 Load Paths

Figures 3-45 and 3-46 illustrate the load path concept for the elevated portion of a building. 

Wind loads collected and concentrated as shown in these figures must be passed through the 

foundation to the ground (see Figure 3-23).
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 3-33

Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family 3

Figure 3-45. Depiction of a building load path

source: FEMA 489
3-34 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

3 PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly

Figure 3-47 shows a house on western Galveston Island that collapsed during Ike. High water 

levels and waves acted on the foundation while winds (blowing from land toward the Gulf of 

Mexico) pushed the house seaward. The result was a foundation failure—the foundation could 

not provide the required load path continuity to the ground without breaking.

Figure 3-46. 

Load path around 

openings and connection 

to foundation pile 

SouRcE: FEMA 499

Figure 3-47. 

Collapse of a West 

Galveston Island, TX, 

house due to foundation 

failure

Broken Pilings
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 3-35

Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family 3

Figure 3-48 shows a house on Bolivar Peninsula that remained standing although severely damaged by surge, waves, and wind. The house survived because its MWFRS and foundation load 

paths remained intact.

Figure 3-48. 

Though much of the 

cladding and structural 

sheathing was destroyed 

by Ike’s surge, the MWFRS 

of this Bolivar Peninsula, 

TX, beach house remained 

intact and connected

Piling connections to floor beams of elevated structures were routinely observed by the MAT. 

However, unless the building was substantially damaged or under construction, most load path 

connections of wall and roof structural elements were covered by building finishes and not visible for inspection. Some beam-to-piling connections were found to be strong and robust as 

seen in Figures 3-49 and 3-50. Many others were weakly connected with nails, too few bolts, or 

columns weakened by deep mortises (Figures 3-51).

Figure 3-49. 

Strong concrete columnto-beam steel saddle 

connector
3-36 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

3 PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly

New construction was frequently observed with robust construction such as sill plates bolted to 

slabs-on-grade, studs clipped to double top plates, and wall-to-roof construction (Figures 3-52, 

3-53, and 3-54).

Figure 3-50. 

Strong interior wood 

column-to-beam 

connector with building 

shear wall connector

Bolted Beam connection

Building Shear Wall connector

Floor Joist (Lollipop) 

connectors

Figure 3-51. 

Poor beam connection to 

corner column
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 3-37

PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly 3

Figure 3-53.

Studs clipped to double 

top plate; rafter-to-topplate connector has yet 

to be installed. Better 

framing practices could 

have avoided some of 

the problems shown in 

this photo. Ceiling joists 

are not well nailed to the 

rafter and may twist in 

the future. The builder 

did not take advantage of 

aligning wall framing and 

rafter framing to simplify 

connections for wind 

loads.

Figure 3-52. 

Studs and sill plate 

connected in new house 

(sill bolts yellow arrows 

and clips red arrows). 

However, sill bolts are 

spaced too far apart (2 feet 

is the maximum spacing 

allowed) and did not have 

3-inch by 3-inch by 1

/8-

inch washers per 2003 

IRC and TDI-adopted IBHS 

guidelines. Blue line shows 

3-foot spacing (Webster, 

TX).
3-38 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

Numerous new and older houses, however, were observed without proper hurricane connections or improperly installed connections (Figures 3-55 and 3-56).

Figure 3-54. 

Wall-to-roof strapping. 

Details for uncommon 

framing details should be 

specifically provided by 

the designer on building 

plans, including specifying 

the specific connection 

and application to ensure 

a continuous load path.

Figure 3-55. 

Toe-nailed connection 

of floor joists on band 

beam on house under 

construction. Floor joist 

should be installed using 

either galvanized metal 

joist hangers or ledger 

beams (LaPorte, TX).
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 3-39

PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly 3

3.1.3 Elevation and Freeboard

The observations of the Ike MAT investigation clearly demonstrate the importance of elevating 

buildings above the flood level, including any effects of waves and floodborne debris. Elevating 

only to the BFE does not guarantee a house will remain free of flood damage during a specific 

hurricane or coastal flood event. As was stated in Section 2.1.1, FISs and FIRMs may not depict 

the true lateral and vertical extents of actual flooding during the base flood event (100-year 

flood event) for a variety of reasons. Nor will construction to the 100-year flood event shown on 

the maps offer protection against floods that exceed the true base flood. 

The key to successful coastal buildings is to construct them higher than the BFE by adding freeboard. The desired amount of freeboard will depend on a number of factors, but the age of 

the FIRM and the nature of the building being 

constructed are the most important factors. Old 

FIRMs tend to be less accurate than newer FIRMs 

in showing the contemporary 1-percent-annualchance flood level. Critical facilities should be 

constructed with higher freeboard than typical 

residential and commercial structures.

Figure 3-56. 

Existing house shear wall 

connector incorrectly 

located (red arrow). 

Connector should be 

located on column line or 

the beam and beam-tocolumn connection should 

be designed to resist 

the uplift load, which 

is carried by a nailed 

connection in the absence 

of bolts (Sunset Crystal 

Beach, Bolivar Island, TX).

The MAT recommends any post-Ike reconstruction and new construction in 

Ike-flooded areas be carried out with a 

minimum of 3 feet of freeboard above the 

BFEs shown on the Effective FIRMs at 

the time of Ike (refer to Section 3.1.1.1 for 

additional information). Freeboard is necessary to compensate for out-of-date flood 

hazard maps and to provide an additional 

degree of flood protection not afforded by 

the Effective FIRMs.
3-40 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

3.1.4 Siting Effects on Structural Performance

While many people recognize that how buildings are constructed will affect flood damage to 

that building (e.g., building floor elevation and foundation design), they may not appreciate the 

importance of where buildings are constructed in determining flood damage. Post-hurricane inspections typically observe the greatest flood damage, loss of coastal buildings, and loss of roads 

and infrastructure in the area closest to the shoreline. This was also the case with Hurricane Ike. 

The greatest damage occurs in the area closest to the water since buildings and infrastructure 

situated there are subject to the most extreme flood forces and conditions during a hurricane, 

i.e., the highest waves and the greatest erosion (Figures 3-57 and 3-58). Buildings situated closest to the shoreline are also at greatest risk for the effects of long-term erosion, sea level rise, and 

other long-term changes affecting the shoreline (see Surfside Beach text box).

Figure 3-57. 

Post-Ike photograph of 

West Galveston Island, 

TX, illustrating increased 

severity of flood damage 

near the shoreline

Figure 3-58. 

Post-Ike photograph of 

Bolivar Peninsula, TX, 

illustrating increased 

severity of flood damage 

near the shoreline
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 3-41

PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly 3

SURFSIDE BEACH, TX

The closer a building is located to the shoreline, the more vulnerable it becomes. This is not only due to 

the increasing flood forces close to the shoreline, but also because a building’s foundation designed for 

a given location and set of conditions (ground elevation, stillwater flood depth, wave height, etc.) will find 

itself exposed to a different set of conditions (lower ground, higher wave height, etc.) as the shoreline 

erodes over time, and the building may not be able to withstand those new conditions. A classic case is 

Surfside Beach, TX, where long-term erosion had resulted in dozens of houses standing on the beach, 

seaward of the line of vegetation. Many of these houses were ordered removed by the State of Texas; 

some were removed, but others remained and litigation resulted. Hurricane Ike destroyed most of the 

houses standing on the beach (see photos below).

The presence of reinforced dunes and revetments and seawalls can reduce damage slightly in 

areas close to the shoreline when those dunes and erosion control structures remain intact during a storm event. However, when they fail they offer little protection to upland buildings. Of 

the structures observed by the MAT, only the Galveston Seawall provided significant protection 

to buildings against wave attack and erosion. The recently completed Surfside Beach revetment 

appears to have survived Ike with minor damage, and undoubtedly offered some protection to 

upland buildings, but this revetment was not subject to the extreme forces that the Galveston 

seawall and shorelines farther east were.

Although wave and erosion effects in the bays were not as severe as on the Gulf coast, buildings 

sited close to the bay shoreline were at increased risk to flood damage, relative to buildings farther from the bay shoreline.
3-42 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

3.2 Envelope Damage

The MAT observed building envelope damage as far west as the west end of Galveston Island, TX, 

and as far east as Terrebonne Parish, LA, a distance of approximately 150 miles. The MAT also 

observed building envelope damage as far inland as the north side of the City of Houston, approximately 45 miles from the coast (see Figure 1-16). Sections 3.2.1 through 3.2.6 describe building 

envelope performance, including roof systems, non-load-bearing walls and wall coverings, doors, 

windows and shutters, soffits and roof ventilation, and exterior-mounted equipment. 

Blow-off of building envelope components frequently results in damage to adjacent buildings 

and vehicles, as well as the building itself. The most notable building envelope issues during 

Hurricane Ike, and the most common windborne building envelope debris, were roof coverings 

and vinyl siding. Figure 3-59 illustrates the magnitude of building envelope debris that occurred 

in some areas.

As expected, the building envelope on older houses did not perform as well as on new houses. Specifically, houses constructed prior to 1985 in Texas and prior to the adoption of the IRC in 2005 in 

Louisiana exhibited the poorest envelope performance. Post-1985 Texas home construction in the 

counties affected by Hurricane Ike were governed by the Texas Windstorm Program (refer to Section 2.3), and all post-2005 houses in Louisiana were governed by the newly adopted IRC. 

The extent and magnitude of envelope damage observed by the MAT was greater than would 

be anticipated given that the estimated actual wind speeds of Hurricane Ike were less than the 

design speeds given by ASCE 7-05 and IRC 2006. The poor performance of the newer houses is 

therefore related to the lack of contractor knowledge of proper hurricane construction, material installations not conforming to manufacturer’s requirements for hurricane zones, and poor 

code enforcement.

Figure 3-59. 

A substantial amount 

of siding (the white 

lines scattered around 

the ground), along with 

roofing materials, blew 

off these West Galveston, 

TX, houses (Hurricane Ike 

estimated wind speed in 

this area: 

90 mph)
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 3-43

PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly 3

3.2.1 Roof Systems

Historically, damage to roof coverings is the leading cause of building performance problems 

during hurricanes. In the rains accompanying a 

hurricane, rainwater entering a building through 

damaged roofs can cause major damage to the 

interior finishes and contents. Unless quick action is taken to dry a building, mold bloom can 

quickly occur in the hot, humid southern climate. Drying of buildings was hampered after 

Hurricane Ike by the lack of electrical power to 

run fans and dehumidifiers. 

The MAT observed a variety of roof coverings, including asphalt shingles, metal panels, metal 

tiles, and tile. In the areas observed by the MAT, roof covering damage was common, and quite 

variable as shown in Figure 3-60. This type of variability is consistent with what was observed by 

the Hurricane Charley, Ivan, and Katrina MATs (see FEMA 488, Hurricane Charley in Florida: Observations, Recommendations, and Technical Guidance [April 2005a]; FEMA 489, Hurricane Ivan 

in Alabama and Florida: Observations, Recommendations, and Technical Guidance [August 2005e]; 

and FEMA 549, Hurricane Katrina in the Gulf Coast: Building Performance Observations, Recommendations, and Technical Guidance [July 2006b]). 

LIQUID-APPLIED ROOF 

COVERING

The MAT observed one residence that 

had a liquid-applied roof covering over a 

concrete deck. FEMA investigations after 

Hurricane Marilyn (1995) in the u.S. Virgin 

Islands found that this type of roof covering 

has excellent wind performance.

Figure 3-60. 

Some of the roofs on 

these Jamaica Beach, 

TX, houses had no roof 

covering damage, while 

one had moderate 

damage (blue arrow) 

and one had extensive 

damage, including loss of 

underlayment (red arrow) 

(Hurricane Ike estimated 

wind speed in this area: 

90 mph)
3-44 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

At several residences, a large amount of roof covering was blown away, as shown in Figures 3-60, 

3-66, 3-67, and 3-69. However, more commonly, roof covering damage was limited to a small 

area such as at corners, eaves, rakes, or ridges. In the case of asphalt shingled roofs, sometimes a 

few shingles in the field of the roof were blown away. Had Hurricane Ike’s winds been closer to 

current design wind speeds, the roof covering damage would likely have been greater. The following subsections present asphalt shingle, metal panel, and tile roof observations.

3.2.1.1 Asphalt Shingles

Most of the residences observed by the MAT had 

asphalt shingle roof coverings. There were two 

notable observations, as discussed below: 1) use 

of shingles that had been tested and labeled in 

accordance with relatively new criteria, and 2) 

the use of roof tape at deck sheathing joints.

New Shingle Labels. Asphalt shingles are now 

available with Class D, G, or H labels (see text 

box). At the time of Hurricane Katrina (2005), 

only a limited number of shingles were available 

with the new ratings. However, several products 

are now available with the new classifications.2

Figure 3-61 shows a shingle bundle wrapper at a 

house under construction at the inset in Figure 

3-61. The shingle bundle wrappers indicate the 

shingles meet Class H (i.e., suitable for up to 150 

mph). The IRC/ASCE 7 design wind speed for 

this locaton is 120 mph, hence use of a Class G 

shingle would have been sufficient. This is the 

first and only house observed by a MAT wherein it was known that shingles meeting one of the 

new Class ratings was installed. There was no apparent wind damage to this house.

The MAT observed several other newly installed roofs, but was unable to determine if the shingles met any of the new classifications. Even if the shingles did meet Class G or H, failure could 

have initiated along the rake, eave, or hip/ridge unless there was special securement (such as 

that shown in Technical Fact Sheet 20, Asphalt Shingle Roofing for High-Wind Regions, in FEMA 

499), as described below.

The newly constructed house shown in Figure 3-62 is on the same block as the one shown in Figure 3-61. Bleeder strips were installed along the rake; however, as discussed in Section 5.4.1.3 of 

the Katrina MAT report (FEMA 549), unless the shingles are hand-tabbed as described in Technical Fact Sheet 20, bleeders do not provide reliable securement.

ASPHALT SHINGLE CLASS 

RATINGS

Testing and labeling is prescribed in ASTM 

D 7158.* The following classes of shingles 

are specified in this standard:

Class D: Suitable for use up to 90 mph

Class G: Suitable for use up to 120 mph

Class H: Suitable up to 150 mph

Class F: Shingles with this classification 

are tested in accordance with the old test 

method prescribed in ASTM D 3161, a test 

method widely recognized as antiquated 

for evaluating the wind resistance of selfsealing shingles 

* Wind speeds cited are design wind speeds 

in IBC/IRC/ASCE 7 (based on Exposure 

C, and a maximum mean roof height of 60 

feet).

2 See the following TDI Web site for product listings: http://www.tdi.state.tx.us/wind/documents/ashglcnf08ibcircrev031009b.pdf
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 3-45

PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly 3

Figure 3-61. 

View of a shingle bundle 

wrapper at the Webster, 

TX, house shown in the 

inset. This shingle has a 

Class H rating (red arrow) 

(Hurricane Ike estimated 

wind speed in this area: 

104 mph).

Figure 3-62. 

Shingle damage at a house 

near the one shown in 

Figure 3-61 (Webster, TX)
3-46 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

3 PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly

Figure 3-63 shows a house under construction on Bolivar Peninsula that lost shingles along the 

eave (it is also shown on the front cover of this report). Failure along eaves commonly occurs because of incorrect application of the starter course and lack of hand-tabbing (as recommended in 

Technical Fact Sheet 20). For further discussion of eave issues, see Section 5.4.1.2 in FEMA 549.

Figure 3-63. 

Loss of shingles along 

the eave in Bolivar 

Peninsula, TX (Hurricane 

Ike estimated wind speed 

in this area: 110 mph)

Figure 3-64. 

Loss of shingles and 

underlayment in a corner 

area, and loss of shingles 

from the field of this roof 

in Bolivar Peninsula, TX 

(Hurricane Ike estimated wind 

speed in this area: 110 mph)

Figure 3-64 shows a house that was reportedly constructed in 2005 on Bolivar Peninsula. It lost 

shingles and underlayment at a corner area (red circle at the inset) and shingles in the field of 

the roof near the exhaust fan (blue arrow). Loss of shingles was likely due to lack of hand-tabbing. These shingles reportedly met Class F.
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 3-47

PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly 3

Figure 3-65 shows a house under construction on Bolivar Peninsula. It lost shingles along the 

hip. Also, at areas along the exposed hip, either the underlayment did not completely lap over 

the hip line, or if it did, portions of the underlayment blew away. Water could leak into the 

building in the vicinity of the two red arrows. Unless hip and ridge shingles are hand-tabbed, as 

recommended in Technical Fact Sheet 20, they are very susceptible to blow-off (for further discussion, see Section 5.4.1.1 in FEMA 549).

Taping of Sheathing Joints. Figure 3-66 shows some relatively new Fortified...for safer living® houses 

in the Audubon Village area of Bolivar Peninsula (refer to Section 3.1.1.1 text box for more information on Fortified...for safer living® homes). 

As shown in Figure 3-66, some of the roof coverings had no apparent damage, but the shingles 

and underlayment were blown off of one roof (red arrow). Also, a portion of the roof overhang 

blew off of one of the houses (blue arrow). When the MAT observed blow-off of roof framing 

and/or sheathing, it typically occurred on older buildings, rather than new construction.

Figure 3-65. 

Loss of hip shingles and portions of the 

underlayment in Bolivar Peninsula, TX 

(Hurricane Ike estimated wind speed in 

this area: 110 mph)
3-48 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

3 PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly

The Fortified...for safer living® requirements include special provisions pertaining to attachment 

of roof underlayment in order to make them more wind-resistant in the event the shingles are 

blown off. The MAT was unable to determine whether or not the failed underlayments complied with the Fortified...for safer living® requirements. However, according to IBHS investigators 

deployed after Hurricane Ike, two layers of #15 felt were installed. (Use of two layers of #15 is 

one of the underlayment options in the current Fortified...for safer living®.) The underlayment 

was attached with plastic capped-head nails, spaced at 6 inches on center along the laps and 12 

inches on center in the field (this spacing is consistent with the original Fortified...for safer living®

spacing guidance). This underlayment and attachment spacing is consistent with underlayment 

Option 2 in Technical Fact Sheet 19, Roof Underlayment for Asphalt Shingle Roofs, in FEMA 499. 

The Fortified...for safer living® requirements also 

include a requirement to tape the sheathing 

joints with a minimum 4-inch-wide modified 

bitumen roof tape. The tape is intended to 

provide an additional line of defense against 

water infiltration in the event the shingles and 

underlayment blow off. The use of roof tape was recommended in the 2000 edition of FEMA 

55 and it is recommended in Technical Fact Sheet 19 in FEMA 499.

Several of the Fortified...for safer living® houses that lost underlayment had taped joints, including 

the one shown in Figure 3-67. However, as shown in Figure 3-68, the taping was not effective. 

Observations by IBHS investigators revealed application problems with the tape. Staples were 

used to attach the tape because bonding problems were experienced during application. Apparently the applicator did not realize the tape was intended to prevent water from leaking through 

the sheathing joints. With the tape in an un-bonded and wrinkled condition, it was incapable 

of fulfilling its intended purpose. Self-adhering modified bitumen roof tape normally bonds 

quite well to sheathing. Bonding problems are commonly attributed to dust on the sheathing, 

Figure 3-66. 

Roof covering and roof 

structure damage at 

Fortified...for safer living®

houses in the Audubon 

Village area on Bolivar 

Peninsula, TX (Hurricane 

Ike estimated wind speed 

in this area: 110 mph)

The IBHS is preparing a report on Audubon 

Village. This report is expected to be available on the IBHS Web site by the end of 

2009. Refer to: www.ibhs.org
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 3-49

PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly 3

wet sheathing, a surfacing on the sheathing that interfered with the bonding, or using inappropriate tape. According to IBHS, problems with bonding self-adhering modified bitumen to 

oriented strand board (OSB) had been previously experienced at a demonstration project. In 

evaluating that demonstration project, IBHS discovered that although the OSB manufacturer 

had recommended application of a primer before installation of the self-adhering modified bitumen because of the presence of a wax on the OSB, a primer had not been installed. 

According to IBHS, the shingles at the Fortified...for safer living® houses at Audubon Village met 

Class H (i.e., suitable for use up to 150 mph).

Figure 3-68. 

This tape did not provide 

a watertight seal. Note 

the wrinkles (which allow 

water migration) and the 

staples (blue arrow) 

that were used to attach 

the tape (Audubon 

Village, TX).

cREDIT: IBHS

Figure 3-67. 

This Fortified...for safer 

living® house had taped 

sheathing joints (red 

arrow)
3-50 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

3 PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly

3.2.1.2 Metal Panels 

Metal panels were the second most common 

type of residential roof covering observed by 

the MAT. However, there were substantially fewer metal roofs than asphalt shingle roofs. Their 

performance was quite varied, as illustrated by 

a new housing area near the west end of the 

Galveston seawall. All of the houses in that area 

(around a dozen) had metal panel roofs. Three 

of the houses experienced panel blow off. Two 

of these failures are shown in Figures 3-69 and 3-70. Fortunately, as shown in the figures, the 

underlayment did not blow away, so it provided leakage protection. The panels shown in Figure 3-69 have snap-lock seams. One side of the seam was attached with concealed fasteners. 

The seam unlatched, but lack of roof access prevented MAT investigation of the cause of the 

unlatching.

Several metal panel roofs performed exceptionally well during Hurricane charley 

(2004), even though they were exposed to 

very high winds. For further discussion, see 

FEMA 488.

For guidance on metal roofs, see Hurricane 

Ike Recovery Advisory, Metal Roof Systems 

in High-Wind Regions (Appendix D).

Figure 3-69. 

These snap-lock seam 

panels were attached with 

fasteners through one side 

of the seam (Galveston 

Island, TX; Hurricane Ike 

estimated wind speed in 

this area: 110 mph)
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 3-51

PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly 3

3.2.1.3 Tile 

The MAT observed very few tile roofs. As with asphalt shingles and metal panels, the performance was quite varied. Figures 3-71 and 3-72 show two houses along the coast of Galveston 

Island. The roof shown in Figure 3-71 was observed from the air and ground. No tile damage 

(including hips) was observed. Figure 3-72 shows damage at hips, the eave, and the field (which 

was likely caused by windblown eave and/or hip tiles.

For further information on tile roof performance, see the MAT reports for Hurricane Charley 

and Hurricane Ivan (FEMA 488 and 489, respectively), wherein a large number of tile roofs 

were observed. For guidance on design and installation of tile, see Technical Fact Sheet 21, Tile 

Roofing for High-Wind Areas, in FEMA 499.

The panels shown in Figure 3-70 were attached with concealed clips, which unlatched from the 

panels. The first row of clips (just above the red line) was several inches from the end of panels; 

this first row should have been within a few inches from the eave.

Figure 3-70. 

These architectural metal 

panels unlatched from 

the concealed clips. The 

red line shows location 

of the first row of clips 

(Galveston Island, TX; 

Hurricane Ike estimated 

wind speed in this area: 

110 mph).
3-52 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

3.2.2 Non-Load-Bearing Walls and Wall Coverings 

This section covers exterior wall coverings (also known as cladding or siding) including brick veneer (Section 3.2.2.1), vinyl siding (Section 3.2.2.2), fiber-cement siding (Section 3.2.2.3), and 

wood and hardboard siding (Section 3.2.2.4). In the area visited by the MAT, the most common 

exterior wall coverings were fiber-cement lap siding; vinyl siding; and panels of wood, hardboard, 

or fiber cement. Although not a prevalent residential cladding, Exterior Insulation Finish System 

(EIFS) was observed in a few locations. Because most of the houses surveyed were elevated, brick 

was predominantly observed on a few commercial or institutional buildings, and on one multifamily residential complex. 

Figure 3-71. 

This tile roof on Galveston 

Island, TX, did not 

experience any wind 

damage (Hurricane Ike 

estimated wind speed in 

this area: 106 mph)

Figure 3-72. 

This tile roof on Galveston 

Island, TX, experienced 

hip, eave, and field 

damage (Hurricane Ike 

estimated wind speed in 

this area: 106 mph)
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 3-53

Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family 3

In Louisiana, the MAT observed a variety of siding and cladding failures, despite the fact that 

wind speeds were less than current code-specified values. The damage observed was mostly, 

but not always, on older buildings, which (presumably) had been designed and constructed 

without full consideration of wind resistance (Figures 3-73 and 3-74).

Figure 3-73. 

Loss of siding due to 

winds, Chauvin, LA 

(Terrebonne Parish; 

Hurricane Ike estimated 

wind speed in this area: 

50 to 60 mph, Exposure B)

Figure 3-74. 

Loss of siding at Holly 

Beach, LA, home (Cameron 

Parish; Hurricane Ike 

estimated wind speed 

in this area 80 mph, 

Exposure C) 
3-54 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

3 PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly

Gable end walls are frequently covered with a non-structural sheathing, such as foam plastic or 

thin fiberboard and gypsum sheets. Because there is no interior wall covering, the sheathing 

and cladding assembly is exposed to the full force of the wind pressure differential between the 

attic and outside. Where this pressure is negative (that is, the side of the house is downwind or 

parallel to the wind direction), substantial suction pressure is exerted against the sheathing, 

which can transfer the load to the cladding and thereby produce cladding failure. The MAT 

observed several cases where both sheathing and cladding over the gable end were blown out 

(Figures 3-75 and 3-76).

Figure 3-75. 

Complete loss of thin 

gypsum sheathing and 

brick veneer from gable 

end (West Bay, Galveston 

Island, TX; Hurricane Ike 

estimated wind speed 

in this area: 90 mph, 

Exposure B)

Figure 3-76. 

Loss of fiberboard 

sheathing and fiber 

cement siding from gable 

end wall of an apartment 

complex (West Bay, 

Galveston Island, TX; 

Hurricane Ike estimated 

wind speed in this area: 90 

mph, Exposure B)

Brick Veneer

Loss of Gypsum Sheathing
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PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly 3

3.2.2.1 Brick Veneer

Numerous brick veneer failures were observed at one Galveston apartment complex. Figure 

3-77 shows failed brick veneer at one complex. The brick ties were randomly spaced with the 

horizontal spacing ranging from 32 inches to 16 inches on-center and the vertical spacing ranging from 48 inches to 24 inches on-center. Many of the corrugated ties were rusted and broken, 

were not embedded in the masonry, or had minimal embedment. Figure 3-78 illustrates common problems with brick veneer installations and Figure 3-79 illustrates proper methods of 

installation.

Figure 3-77. 

Collapsed brick veneer wall with brick ties 

at varied spacing, some of which were only 

partially imbedded or not embedded (West 

Bay, Galveston Island, TX; Hurricane Ike 

estimated wind speed in this area: 90 mph, 

Exposure B)

Brick Tie Not Embedded to 

Masonry

Gypsum Sheathing Substrate
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3 PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly

The Brick Industry Association’s (BIA’s) Technical Notes 28 Anchored Brick Veneer, Wood Frame 

Construction (2002) specifies a maximum tie spacing of 24 inches in each direction for 16-inch 

stud spacing for buildings in standard 90-mph wind zones. Table 3-1 indicates the required tie 

spacing for high wind zones. Though Galveston experienced less than design wind speeds, the 

proximity of the adjacent complex shown in Figure 3-77 may have produced increased wind 

pressures, thereby producing the catastrophic failure of the poorly anchored brick veneer. However, the installed tie spacing was not suitable for this back bay Galveston location with a design 

wind speed of 120 mph. 

FEMA Hurricane Ike Recovery Advisory, Attachment of Brick Veneer in High-Wind Regions (Appendix D), provides recommended practices for brick veneer attachment. The advisory is based on 

observations from Hurricanes Ivan, Katrina, and Ike.

Figure 3-79. Proper installation and embedment of corrugated brick ties

Figure 3-78. Misalignment of the tie reduces the embedment and promotes veneer failure
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Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family 3

Table 3-1. Brick Veneer Tie Spacing

Wind Speed (mph)

(3-Second Peak Gust) Wind Pressure (psf) Maximum Vertical Spacing for Ties (inches)

16-inch stud spacing 24-inch stud spacing

90 -19.5 24a,b 16a

100 -24.1 24a,b 16a

110 -29.1 201⁄2 b 131⁄2

120 -34.7 17 NAc

130 -40.7 15 NAc

140 -47.2 13 NAc

150 -54.2 11 NAc

Notes:

1. The tie spacing is based on wind loads derived from Method 1 of ASCE 7-05, for the corner area of buildings up to 30 feet 

high, located in Exposure B with an importance factor (I) of 1.0 and no topographic influence. For other heights, exposures, or 

importance factors, engineered designs are recommended.

2. Spacing is for 2 1⁄2-inch long 8d common (0.131-inch diameter) ring-shank fasteners embedded 2 inches into framing. Fastener 

strength is for wall framing with a Specific Gravity G=0.55 with moisture contents less than 19 percent and the following 

adjustment factors, Ct=0.8; and CD, CM, Ceg, and Ctn=1.0. Factored withdrawal strength W'=65.6#.

3. The brick veneer tie spacing table is based on fastener loads only and does not take into account the adequacy of wall framing, 

sheathing, and other building elements to resist wind pressures and control deflections from a high-wind event. Prior to repairing 

damaged brick veneer, the adequacy of wall framing, wall sheathing, and connections should be verified by an engineer.

a Maximum spacing allowed by the American Concrete Institute (ACI) 530-08.

b In locales that have adopted the 2006 IBC/IRC, the maximum vertical spacing allowed by ACI 530-05 is 18 inches.

c 24-inch stud spacing exceeds the maximum horizontal tie spacing of ACI 530-08 prescribed for wind speeds over 110 mph.

3.2.2.2 Vinyl Siding

Vinyl siding was the most frequently used exterior cladding and was found in all the areas 

observed by the MAT, on both newer and older buildings. Vinyl siding was observed to be commonly used to re-cover older wood cladding (Figure 3-80). Panel widths observed were typically 

between 8 and 12 inches, with double-four (two 4-inch) faces, double-five, and triple 3 1⁄2-inch 

profiles being the most common. Siding was most commonly installed over plywood or OSB 

sheathing, and usually, with a water-resistant barrier (house wrap) over the sheathing. Where the 

siding was covering older wood plank or panel siding, a layer of foam sheathing was frequently 

applied. The foam sheathing, typically 1⁄2-inch to 1-inch extruded polystyrene sheets, served as 

both additional thermal insulation and flat substrate against which to place the siding.
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3 PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly

Vinyl siding failure was frequently initiated at the building corners and along the bottom edges 

of elevated houses. The higher wind corner pressures produced unlatching along the bottom 

strip that resulted in the unzipping of the entire wall (Figure 3-81). When vinyl siding was blown 

off, the water-resistant barrier (either asphalt-saturated felt or housewrap) was often blown away. 

Though not witnessed by the MAT, this loss of the siding and underlayment could have allowed 

wind-driven rainwater to enter the wall cavity and the house, thereby causing water damage to 

interior finishes and contents. Vinyl siding and soffits that become windborne debris can potentially break unprotected glazing.

The most important factors influencing whether vinyl siding will remain on the wall during a 

high wind event are: (1) selection of siding appropriate for the basic wind speed at the location, 

and (2) the use of proper application techniques and installation details. The latter category 

includes use of proper accessories such as starter strips, receivers and utility trim; nail selection 

and placement; and locking of successive panel courses to each other.

Detachment of vinyl siding attributed to application deficiencies is frequently seen after high 

wind events (e.g., excessive spacing between fasteners and improper nail head size of the fasteners). In other cases, while proper fastening may have been used, the type of vinyl siding used 

may not have been appropriate for use in high wind locations. 

Figure 3-80. 

Typical vinyl siding failure. Vinyl was installed 

over older wood cladding (red arrows) (Sea 

Isle, TX; Hurricane Ike estimated wind speed 

in this area: 95+ mph, Exposure C).
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Siding that is intended for locations with a basic wind speed greater the 110 mph usually has a 

double-layer nail hem (Figure 3-82). This double layer strengthens the vinyl at the point where 

the nail attaches so the siding better resists tearing or pull-through of the nail head. Conventional vinyl siding has a single-layer nail hem. Most of the siding that was removed from the 

wall (and therefore exposed for inspection by the MAT) had a single nail hem and was thus 

not likely to have been rated for high wind locations. Although it is possible that the siding that 

stayed on the wall (and therefore wasn’t inspected) was predominantly high-wind rated, it seems 

likely that a significant percentage of the siding installed in the high wind zones of this area of 

the Texas coast is not intended for that application. This conclusion would appear reasonable, 

since winds produced by Ike varied from maximum 3-second gusts of 90 mph on the west end 

of Galveston to 110 mph on the east end of Bolivar Peninsula, and the ASCE 7-05 assigned wind 

speeds for these locations is 130 mph.

Figure 3-81. Improper installation led to extensive loss of siding up the house wall. The bottom lock of the lowest 

course of siding was cut off, and utility trim substituted for the correct starter strip. The poorly retained bottom 

edge pulled out under wind pressure, leading to extensive loss of siding up the house wall (Tiki Island, TX; 

Hurricane Ike estimated wind speed in this area: 88 mph, Exposure B).
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3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

As with any building system, even high-wind rated siding needs to be properly installed in order 

to function as designed. The MAT observed several common installation methods that tended 

to allow siding to be blown from the building by Hurricane Ike, including:

1. Starter strip attachment along the first (lowest) course of siding 

Starter strips consist of a nail hem and locking profile that matches the shape of the lock on the 

lower edge of the siding panel (called the buttlock). The starter strip is fastened to the lowest 

part of the wall and the first course of siding is locked into it. If this lock is not strong, wind can 

get under the first course and detach it from the starter strip. The loose piece of siding will place 

stress on the lock of the course above, as well as its own nail hem, leading to successive loss of 

courses up the wall. In order to protect against this, the starter strip should be designed for use 

with the particular profile (shape) of siding being used, and the siding should be firmly locked 

into the starter strip.

Proper use of the starter strip is particularly important with elevated structures, where the wind 

passes at high velocity underneath the structure as well as against the walls. On Galveston Island, 

Bolivar Peninsula, and Tiki Island, where elevated houses were predominant, a large percentage of siding loss originated at the lowest course and led to loss of the courses above. The MAT 

saw numerous instances where a “generic” starter strip (having just a bulge, rather than a lock 

shaped to match the siding) was used. In other cases, J-channels, which do not lock into the 

panel at all, or field-fabricated substitutes for starter strips were used. Elevated structures with 

poorly implemented starter strips were most vulnerable to siding loss starting at the lowest edge 

of the elevated wall (Figure 3-83). 

Vinyl siding installers should be advised to use starter strips that are specifically designed for 

the brand and model or profile of the siding that will be used and generic starter strips should 

be avoided. Installers should consult the manufacturer’s instructions to identify the starter 

Figure 3-82.

Vinyl siding rated for high 

wind has a double-layer 

nail hem
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strip to be used. Installers should also test the fit of the starter strip to the siding to make sure 

it locks securely before installing. On elevated structures, the starter strip should not extend 

below the lowest edge of the vertical wall or the exposed edge may catch the wind blowing 

under the house.

2. Locking of mid-wall siding courses

Siding loss frequently begins midway up the wall rather than at the bottom course. Many of 

these instances are the result of failure to fully and securely lock the buttlock of the siding into 

the locking shape of the siding course below. This can happen when the siding is pulled up too 

tightly before being nailed, thereby placing it under tension when the siding is not fully pushed 

Figure 3-83. 

Use of a generic starter strip contributed to loss of siding 

on this house. The shape of the starter strip did not properly 

match the shape of the siding, and the relatively weak strip 

bent up at the end and released the siding lock (blue inset). 

The edge of the starter strip also extended slightly below the 

edge of the building, which further contributed to the failure 

(red inset) (Tiki Island, TX; Hurricane Ike estimated wind 

speed in this area: 88 mph, Exposure B).
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3 PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly

into the lock (Figure 3-84), or when the siding is allowed to sag before nailing. These modes of 

failures frequently occur when installers try to align the horizontal course lines on one wall with 

those of an adjacent wall by installing several courses loosely.

Each course of siding should be installed by pushing the buttlock firmly upward into the lock 

of the course below until it snaps into place and goes no further. The siding should be held in 

the lock by pushing up from the bottom while the first several fasteners are placed to hold it in 

position. Siding should never be pulled up from the nail hem. When properly installed, siding 

should be able to slide back and forth without undue force; neither tight fasteners at the nail 

hem nor friction in the buttlock should prevent the siding from sliding. Installers should properly locate the starting points for siding on adjacent walls and check alignment of horizontal 

lines every course or two to avoid needing to make adjustments further up the wall. 

Figure 3-84. 

Loosely locked panel led 

to the siding failure of 

this Tiki Island, TX, house. 

The buttlock should be 

fully inserted into lock of 

panel below (Hurricane 

Ike estimated wind speed 

in this area: 90 mph, 

Exposure B).
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PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly 3

3. Using utility trim at windows and other locations where the top edge of siding must be 

removed

When a course of siding intersects the bottom of a window or other large opening, a section 

of the top portion of the panel must be removed to fit around the window. With the nail hem 

removed, special techniques must be used to stabilize and secure the cut edge of siding. An 

accessory called utility trim must be installed beneath the window. The cut edge of the siding 

panel is notched with a snap lock punch. The edge of the siding is inserted into the utility trim, 

which grabs and holds the punched notches (Figure 3-85). A furring strip may need to be used 

underneath the utility trim to place it at the right level to match the angle of the siding. An 

overlap between adjacent siding panels should never be located directly beneath a window or 

similar opening (Figure 3-86). The same technique must be used to finish the top course of siding where the nail hem is cut off to match the location of the eave line.

Figure 3-86. 

Siding partially detached 

by wind as a result of 

improper placement 

of joint directly under 

window. Factory-notched 

end is not held by utility 

trim (Tiki Island, TX; 

Hurricane Ike estimated 

wind speed in this area: 

88 mph).

Figure 3-85. 

Use of utility trim under window to securely attach 

cut and notched siding section

SouRcE: VSI INSTALLATIoN MANuAL
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3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

Although most cases of vinyl siding loss can be traced to improper installation techniques or use 

of incorrect products and accessories, there is room for improvement in product testing and 

documentation. It is recommended that the vinyl siding industry reevaluate the test standards 

used for validating the strength of the siding material and its installation. ASTM D 3679, Standard Specification for Rigid Poly (Vinyl Chloride) (PVC) Siding, specifies a 1.5 product safety factor. 

Given the MAT observations, this safety factor appears to be too low. ASTM D 5206, Standard Test 

Method for Windload Resistance of Rigid Poly (Vinyl Chloride) (PVC) Siding, tests the product installations using a static load. Considering the flexible nature of vinyl siding and the dynamic nature 

of wind loading, a dynamic test appears to be prudent for vinyl siding. Manufacturers should 

provide clearer and more explicit information in the product literature (including Web sites) 

and installation instructions on high-wind applications, including explicit information on:

n Windload ratings for specific products and profiles, and any limitations or conditions 

needed to achieve the rated performance

n Specific accessories (e.g., starter strips, trim pieces) needed to provide the rated 

performance

n Any applicable fastener specifications, spacing frequency, and installation details needed 

for high-wind applications

3.2.2.3 Fiber Cement Siding

The MAT observed fiber cement siding on many residential structures, primarily as a reside 

cladding (Figure 3-87).3

 The observations included lap (plank) siding of varying exposures, perforated soffit material, and siding panels and sheathing material below elevated structures.

Figure 3-87. 

Fiber cement plank siding, 

installed as a reside over 

the original plywood 

siding, was torn from 

this West Bay, Galveston 

Island, TX, house 

(Hurricane Ike estimated 

wind speed in this area: 

100 mph, Exposure C)

3 Reside cladding relates to the installation of a cladding material over an original cladding, usually sandwiched between foam 

board insulation and house wrap.
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Lap siding damage varied from the loss of a few planks to entire walls (Figure 3-88). In most cases, the siding had been blind nailed at each stud (Figure 3-89), which is standard for non-high 

wind zones. Published ratings and ICC Evaluation Reports for the application of fiber cement 

lap siding in high wind zones require that the siding be face nailed through both layers of siding 

at the lap joint, shown in Figure 3-90. The spacing of the nails (16-inch or 24-inch) and permitted material exposure is dependent upon the thickness and width of the siding boards and wind 

zone.

Figure 3-89. 

Damaged fiber cement 

plank siding. Note that 

blind nailing alone (red 

arrows) is recommended 

only for 90-mph or less 

installation. Higher wind 

zone installations should 

include both blind and 

face nailing (Hurricane 

Ike estimated wind speed 

in this area: 93 mph, 

Exposure B).

Figure 3-88. 

Fiber cement lap siding 

was blown off this West 

Bay, Galveston Island, 

TX, house (Hurricane Ike 

estimated wind speed 

in this area: 100 mph, 

Exposure B)
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3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

Another area of vulnerability for fiber cement siding is the exposure of the underside of the 

first course of lap siding, or the bottom edge of panel siding. In setting the first (lowest) course 

of lap siding, a shim is used to place the board at the proper angle. If the shim is not flush with 

the bottom of the board, a lip is formed that can catch wind pressure, and force this board up. 

The first board acts as a lever under the second, and loss of siding progresses up the wall. This is 

a particular issue with elevated structures, where the wind accelerates under the building. The 

MAT observed numerous cases where a projecting lip of the first course on an elevated structure 

led to significant loss of siding (Figure 3-91). If the bottom edge of the panel extends below the 

lowest edge of the elevated structure, or there is a gap between the panel and the lowest structural member, wind pressure can catch the edge and pry the panel off. 

Shims under lap siding should be placed flush with the bottom of the first course, and panel 

siding should be fastened tightly to the substrate so that no gap is created at the lowest edge. 

Consideration should be given to placing a trim piece below the lower edge of the siding to 

fully close off the edge. Neither lap siding nor panel siding should extend below the lowest 

structural member of an elevated building, where it would be exposed to the full force of the 

wind (Figure 3-92).

Figure 3-90. Standard wind zone installation High wind zone installation
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Figure 3-92. 

Loss of fiber cement panels due to lower edge exposure. Inset shows 

lower edge exposed to wind (Bolivar Peninsula, TX; Hurricane Ike 

estimated wind speed in this area: 110 mph, Exposure C).

Figure 3-91. 

Shim placement (red 

arrow) allowed the lower 

edge (red circles) of siding 

to be exposed, resulting 

in loss of siding at several 

locations around this 

elevated structure on 

Bolivar Peninsula, TX. Note 

the blind nailing shown 

by blue arrows (Hurricane 

Ike estimated wind speed 

in this area: 110 mph, 

Exposure C).

Edge of panel extends below 

structural member; exposed to wind.

Shim
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3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

3.2.2.4 Wood and Hardboard Siding

Most of the older houses on Galveston Island, Tiki Island, and Bolivar Peninsula that were originally constructed with plywood or hardboard siding had been re-sided with either vinyl or fiber 

cement siding. The performance of the remaining plywood and hardboard siding was basically a 

function of maintenance. The clapboard-sided house shown in Figure 3-93 was well maintained 

and performed well, though the second floor failure was produced when a non-breakaway wall 

was destroyed by surge. Failure of the plywood siding shown in Figure 3-94 appeared to be the 

result of decayed plywood removed by the wind pressures.

Figure 3-94. 

Decayed plywood 

siding removed by wind 

pressures (Tiki Island, TX; 

Hurricane Ike estimated 

wind speed in this area: 

103 mph, Exposure C)

Figure 3-93. 

Clapboard-sided house 

with siding that performed 

well; damage resulted 

from failure of a nonbreakaway wall (Tiki 

Island, TX; Hurricane Ike 

estimated wind speed 

in this area: 103 mph, 

Exposure C)
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Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family 3

3.2.3 Doors

Failure of an exterior door has two important consequences. First, the failure can cause a rapid 

increase in internal pressure, which may lead to exterior wall, roof, interior partition, ceiling, 

or structural failure. Second, wind can drive rainwater through the opening, causing damage to 

interior contents and finishes, and leading to the development of mold. The essential elements 

of good high-wind door performance include product testing to ensure sufficient factored 

strength to resist design wind loads (both static and cyclic loading); suitable anchoring of the 

door frame to the building; proper flashing, sealants, tracks, and drainage to minimize water intrusion into wall cavities or into occupied space; and, for glazed openings, the use of laminated 

glass or shutters to protect against windborne debris damage, as discussed in Section 3.2.4.

Many door failures observed by the MAT were the result of flood loads, which doors are not designed for. Personnel door failures in slab-on-grade houses and houses elevated below the BFE 

were commonly seen, along with catastrophic failure of the entire house. Garages with garage 

doors are frequently installed below elevated homes, and are designed to fail due to flood loads 

in conjunction with breakaway walls. 

3.2.4 Windows and Shutters

Most building codes incorporate the wind provisions from ASCE 7-05 and require that buildings 

within the most hazardous portion of the hurricane-prone region, called the windborne debris 

region, be equipped with shutters or impact-resistant glazing and designed as enclosed structures. The 2003 IRC allows a residence without either protection to be designed as a partially 

enclosed structure (as if the windows and doors are broken out). Designing a partially enclosed 

structure typically requires upgrading structural components and connections. In Texas, the 

TDI requires opening protection for both Seaward and Inland I zones (refer to Figure 3-69 for 

wind zone locations). Few impact-resistant glazed window units were observed by the MAT, with 

homeowners and builders generally opting to use shutters to provide debris impact protection. 

However, the MAT observed four new houses being constructed on the east beach of Galveston 

Island that were installing impact-resistant glazing (Figure 3-95).
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3 PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly

The MAT observed that glazing at most houses was protected by some form of shutter. The shutter types varied from simple plywood to roll-down shutters. Figures 3-96 to 3-101 show a variety 

of shutters seen by the MAT.

Figure 3-95. 

Impact-resistant door and window glazing in new East Galveston, TX, house. Inset shows manufacturer’s label 

indicating glazing is impact resistant.

Figure 3-96. 

Clear Lake, TX, house 

with plywood shutters 

installed on the accessible 

first floor and roll-down 

shutters installed on the 

less accessible second 

floor (Hurricane Ike 

estimated wind speed 

in this area: 90 mph, 

Exposure B)
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Figure 3-97. 

Tiki Island, TX, house 

with adjustable shutters 

(Hurricane Ike estimated 

wind speed in this area: 

103 mph, Exposure C)

Figure 3-98. 

Texas City, TX, house with 

corrugated clear plastic 

shutters (Hurricane Ike 

estimated wind speed 

in this area: 88 mph, 

Exposure B)
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3 PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly

Figure 3-99. 

Traditional wood swinging 

shutters on Tiki Island, TX 

(Hurricane Ike estimated 

wind speed in this area: 

103 mph, Exposure B)

Figure 3-100. Corrugated 

metal shutters on house 

in West Galveston, TX 

(Hurricane Ike estimated 

wind speed in this area: 

95 mph, Exposure C)
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Since Ike’s winds were below design wind speeds in both Texas and Louisiana, no failures or debris impacts were observed. The 2006 IRC/IBC and TDI require that all shutters be attached to 

the building structure and not to the window frame, siding, or veneer (Figure 3-102); they require 

that all shutters be tested to ASTM Standards E 1886 and E 1996. The MAT observed plywood 

shutters mounted directly to the wall cladding or window frame as seen in Figure 3-103. Further 

information regarding shutters can be obtained from Technical Fact Sheet 26, Shutter Alternatives, 

in FEMA 499.

Figure 3-101. 

Snapped-on vinyl canvas 

window covers (red 

arrows) in West Bay, 

Galveston Island, TX 

(Hurricane Ike estimated 

wind speed in this area: 

90 mph, Exposure B)
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3 PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly

Figure 3-102. Common methods for plywood shutter attachment to wood-frame and masonry walls 

SouRcE: FEMA 499 TEcHNIcAL FAcT SHEET 26

Figure 3-103. 

Plywood shutters installed 

into the wall cladding (red 

circles) in Clear Lake, TX 

(Hurricane Ike estimated 

wind speed in this area: 

90 mph, Exposure B)
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Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family 3

3.2.5 Soffit and Roof Ventilation

Hurricane winds can drive large amounts of water through attic ventilation openings. The accumulating water soaks insulation, which can lead to mold growth and, in some cases, to the 

collapse of ceilings. Attic ventilation can be provided by a number of devices, most of which 

have been observed to allow water intrusion under certain conditions and some of which have 

been observed to blow away. These devices include:

n Soffit vents

n Ridge vents

n Gable end vents

n Off-ridge vents (not observed by Ike MAT)

n Gable rake vents (not observed by Ike MAT)

n Mechanical vents – wind-powered turbines or electric-powered fans (not observed by Ike MAT)

3.2.5.1 Soffits

The opening created where a roof extends beyond the plane of the wall below (called eaves 

on the downslope side of a roof and a rake for the end of a gable roof) is normally closed off 

with a soffit. Soffits typically have small openings, slots, or perforations to provide ventilation 

to the attic, this ventilation is particularly important in the hot, humid climate of coastal Texas 

and Louisiana. Soffit venting allows air to enter the attic space, circulate through the attic, and 

be exhausted through passive vents (ridge vents, gable-end vents) or mechanical vents (either 

wind-powered turbines or electric-powered fans). The soffits along the roof eave and rake are 

the primary line of defense against entry of wind-driven rain into attics. Rain driven into attics 

can cause significant damage as water soaks through ceiling materials and into the interior of 

the building. 

In non-high wind regions, a soffit is typically attached with fasteners to the roof structure only 

on one side—on the house side or to the underside of the fascia—if at all. In such installations, 

the channel formed by a bend in the fascia cover receives and supports the end of the soffit. In 

high-wind zones, most soffit manufacturers indicate the soffit should be attached at both ends 

and at intermediate points so that there is no span greater than 12 inches.

The primary materials observed for roof soffits in the surveyed area were vinyl, aluminum, fiber 

cement, and plywood. In general, fiber cement and plywood soffits remained connected to the 

house (Figure 3-104), while vinyl and aluminum soffits were more likely to have blown off.

By far the most frequently observed form of failure was loss of the aluminum fascia cover from 

the fascia board (the vertical board used to close off the end of eave spaces or form the outer 

edge of the rake), as shown in Figures 3-105 and 3-106. The fascia cover normally covers the 

ends of vinyl and aluminum soffits. Aluminum fascia covers are typically nailed every few feet 

along the length with color matched trim nails. The IRC currently has no guidelines for the installation of fascia covers. Vinyl fascia covers are also available. They are typically installed using 
3-76 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

3 PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly

utility trim along the upper side of the fascia board. The continuous nature of the attachment 

may provide better wind resistance than the aluminum covers. The MAT did not observe any 

vinyl fascia covers. 

Figure 3-104. 

Fiber cement soffit 

remained connected; soffit 

vent slots shown with 

red arrows. Fiber cement 

plank siding was damaged 

(Tiki Island, TX; Hurricane 

Ike estimated wind speed 

in this area: 88 mph, 

Exposure B).

The frequent loss of fascia covers is a significant concern. In most instances where the fascia cover was observed by the MAT to be fully or partially removed, the soffit itself remained in place 

or lost only a few sections, as further shown in Figures 3-105 and 3-106. The loss of the fascia 

cover can increase the risk of loss of the soffit. Even where the soffit remains, rain can be driven 

directly past the exposed soffit ends. The MAT did not have access to the interior of houses to 

determine whether interior moisture damage was a frequent result of fascia cover loss, but such 

damage would be expected. 

The frequency of fascia cover failure suggests that design and installation of this component 

needs to be better addressed in construction standards for buildings in high wind locations. 

The fact that most soffits stayed in place despite loss of the fascia cover suggests that most soffit 

installations were performed properly or the design was sufficiently robust to resist winds that 

occurred during Ike. However, loss of soffits exposed by fascia cover removal would likely have 

been much greater had winds approached design speeds.
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3.2.5.2 Ridge Vents 

The exhaust portion of the attic ventilation system includes ridge vents, gable end vents, off 

ridge vents, and mechanical vents. The MAT only observed damage produced by ridge vents 

and gable end vents. To accommodate the ridge venting system, roof decking is cut or left short 

of the gable ridge beam. Buildings can be retrofitted for ridge vents by cutting the gable slot in 

the existing deck. The ridge vent is normally the last part of the roof cover to be installed. The 

ridge vent should be a tested assembly with a baffle in front of the vent tube that provides passageway for hot attic gases to escape. The baffle is intended to trip any flow of wind and water 

Figure 3-105. 

Loss of aluminum fascia 

cover (red arrows) 

exposed ends of vinyl 

soffit (blue arrows) to 

direct entry of winddriven rain (Tiki Island, TX; 

Hurricane Ike estimated 

wind speed in this area: 88 

mph)

Figure 3-106. 

Loss of fascia cover (red 

arrow) led to loss of soffit 

(blue arrow), exposing the 

attic to wind-driven rain 

(San Luis, TX; Hurricane 

Ike estimated wind speed 

in this area: 93 mph, 

Exposure C)
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3 PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly

blowing up the surface of the roof and deflect it over the top of the roof ridge. The ridge vent 

should be installed with stainless steel screws, not roofing nails, into the roof structure. The 

MAT team was unable to climb onto residential roofs, but it was reported by the homeowner 

that the damage to a second floor ceiling shown in inset of Figure 3-107 was the result of a leaking ridge vent.

Figure 3-107. 

The roof ridge vent (red 

arrows) on this Bolivar 

Peninsula, TX, home 

leaked, and it is presumed 

that the water was shed 

down the underside of 

the roof decking and/

or structure, thereby 

producing ceiling damage 

along the wall of this 

second story room 

(Hurricane Ike estimated 

wind speed in this area: 

110 mph, Exposure C)

3.2.5.3 Gable End Vents

Virtually all gable end vents (Figure 3-108) will leak when the wall they are mounted on faces 

into the wind-driven rain. The pressure developed between the outside surface of the wall and 

the inside of the attic are sufficient to drive water uphill for a number of inches and, if there is 

much wind flow through the vent, water carried by the wind will be blown considerable distances into the attic. Remedial measures include installing shutters, preferably on the outside of the 

house (Figure 3-109). The gable end vent shown in Figure 3-110 was not attached to the building structure and was blown off the apartment building.

Refer to FEMA Hurricane Ike Recovery Advisory, Minimizing Water Intrusion Through Roof Vents 

in High-Wind Regions (Appendix D), for further discussion of off-ridge vents, gable-end rake 

vents, and mechanical vents.
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Figure 3-108. Gable end vent (red arrow) Figure 3-109. Shuttered gable end vent (red arrow)

Figure 3-110. 

Gable end vent blew off this Galveston, TX, 

Back Bay apartment building (Hurricane Ike 

estimated wind speed in this area: 90 mph, 

Exposure B)

3.2.6 Exterior-Mounted Equipment

Residential condensing units should be elevated in floodprone areas. Condensers at many residences observed by the MAT were supported on cantilevered platforms as shown in Figure 

3-111. Cantilevered platforms are preferred because they are less susceptible to damage from 

floodborne debris impacts than are pile or knee-brace supported platforms. Outside floodprone 

areas, condensers are normally mounted at grade or on rooftops. In all cases, the units should 

be permanently anchored to prevent them from being moved (Figure 3-112).
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3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

Maintenance should be considered in the design and installation of elevated supports. Figure 

3-113 shows a unit that is closely caged, making maintenance difficult. If units are caged, the 

railings should either be removable or the platform made sufficiently large to allow service to 

the unit. Further information regarding equipment protection can be obtained from Technical 

Fact Sheet 29, Protecting Utilities, in FEMA 499.

Figure 3-111. 

Typical cantilevered 

condenser (Jamaica 

Beach, TX; Hurricane Ike 

estimated wind speed 

in this area: 80 mph, 

Exposure B)

Figure 3-112. 

Improperly secured 

condensing unit was 

knocked from its platform 

(Kahala Beach, TX; 

Hurricane Ike estimated 

wind speed in this area: 

80 mph, Exposure B)
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3.3 Other Damage

3.3.1 Breakaway Walls

The Ike MAT found that solid breakaway walls performed as expected in the vast majority of cases. The walls broke free without causing significant or structural damage to elevated buildings. In 

some cases, failure of the breakaway walls led to propagation of damage to the building exterior 

above the lowest floor (Figure 3-114). In other cases, attachment of utilities to breakaway walls either prevented their successful breakaway, or contributed to utility damage (Figure 3-115).

Figure 3-114. 

Propagation of damage 

above lowest floor when 

breakaway walls broke free 

(Seabrook, TX)

Figure 3-113. 

Elevated condenser is tightly 

enclosed, making service 

access difficult (Bermuda 

Beach, TX; Hurricane Ike 

estimated wind speed in this 

area: 95 mph, Exposure C)
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3 PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly

The MAT did not document specific cases where breakaway wall panels from one building led 

to identifiable damage to adjacent buildings. However, the ubiquitous presence of breakaway 

walls beneath elevated buildings would undoubtedly increase the quantity of floodborne debris 

during a severe flood event, and could potentially contribute to damage at adjacent structures. 

The MAT observed some breakaway walls in excess of 11 feet high (Figure 3-116). While FEMA 

promotes elevating houses above the BFE (i.e., adding freeboard), one of the unintended consequences appears to be an increased size of floodborne debris elements due to the presence 

of these taller breakaway walls.

The MAT observed that louvered panels remained intact longer than solid breakaway walls under the same flood conditions. As a result, houses with louvered panels had less flood-related 

damage (and repair cost) and contributed less floodborne debris. Figure 3-117 shows louvered 

panels that allowed Ike floodwaters to pass into and out of the below-BFE enclosure without 

damage to the louvered panels. These louvers were installed on the same building shown in 

Figure 3-116, where the solid breakaway wall panel was displaced by floodwaters trapped inside 

the enclosure.

Figure 3-115. 

Attachment of utilities to 

breakaway wall may have 

prevented the wall from 

breaking away, thereby 

resulting in additional 

damage to the structure 

(Galveston Island, TX)
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 3-83

Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family 3

Figure 3-116. 

This 11-foot high breakaway wall panel was pushed 

out by floodwaters trapped inside the enclosure 

(Galveston Island, TX)

Figure 3-117. 

Louvered panels allowed 

Ike floodwaters to pass 

into and out of the belowBFE enclosure without 

damage to the panels. 

The building shown here 

is the same as in Figure 

3-116, where a solid 

breakaway wall panel 

broke away.
3-84 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

Numerous building owners in one community 

(Tiki Island, TX) were observed to be replacing solid breakaway walls lost during Ike with 

louvered panels (Figure 3-118). This action will 

reduce future flood damages and can result in 

lower flood insurance premiums. Zone V flood 

insurance premiums are much less for a building 

with a below-BFE enclosure formed by louvers 

than for a building with an enclosure formed by breakaway walls. A building with an enclosure 

formed by louvers is classified the same as if it had insect screening or open lattice, i.e., as “free 

of obstructions,” while a solid breakaway wall enclosure results in a “with obstruction” rating for 

the building.

Based on these observations, the Ike MAT 

recommends the use of louvered panels 

rather than solid breakaway walls below the 

BFE. See the Hurricane Ike Recovery Advisory, Enclosures and Breakaway Walls, in 

Appendix D for more details on this topic. 

Figure 3-118. 

Solid breakaway walls 

lost during Ike are being 

replaced with louvered 

panels (Tiki Island, TX)

3.3.2 Sheathing on the Underside of Elevated Buildings

Sheathing is typically installed on the underside of the lowest-floor joists on elevated buildings. 

Besides protecting batt insulation that is placed between joists, sheathing can also protect electrical and plumbing lines from floodborne debris. A variety of sheathing materials are used, 

most often sheets of plywood, hardboard, or fiber cement panels. The sheathing is sometimes 

covered with vinyl soffit material, or left uncovered and painted. 

In locations where the water level or waves reached the elevation of the building, sheathing and 

any covering was frequently found to be partially or completely removed (Figures 3-119 and 

3-120). This was particularly true of the thinner panel types, such as 1⁄8-inch fiberboard. Other 

forms of damage, such as gouges from floodborne debris, were observed on the underside of 

panels.
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PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly 3

Figure 3-119. 

Plywood sheathing 

removed by storm surge 

(Jamaica Beach, TX, house 

on West Bay)

Figure 3-120. 

Fiber cement board 

sheathing (red arrow) 

was removed from the 

underside of this house, 

which was elevated 

approximately 12 feet 

above ground level (Bolivar 

Peninsula, TX)

Several examples of vinyl soffit attached directly to floor joists, without sheathing, were observed 

by the MAT (Figure 3-121).

Where floodwaters did not reach the underside of the building, damage due to wind accelerating underneath the building was often observed. In these cases, vinyl soffit was often blown 

off. In some cases, but not all, the sheathing above the soffit was also removed. The vinyl soffit 

covering on the Tiki Island house shown in Figure 3-122 was probably blown off by wind action 

rather than storm surge.

Plywood Sheathing
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3 PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly

For further information on the performance of sheathing on the underside of elevated buildings, see FEMA 489.

Figure 3-121. 

Tiki Island house with 

vinyl soffit applied without 

sheathing removed by 

storm surge (netting was 

used to contain insulation 

in joist space)

Figure 3-122. 

Vinyl soffit covering 

over plywood sheathing 

partially removed (Tiki 

Island, West Galveston 

Bay; Estimated Hurricane 

Ike wind speed: 103 mph, 

Exposure C) 

Vinyl Soffit
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 3-87

Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family 3

Many of the slabs failed once they were undermined. Where the piles were embedded deep into 

the ground, the slab was either undermined (and sometimes settled) as shown in Figure 3-124, 

or the slab collapsed without visible damage to the foundation (Figure 3-125).

3.3.3 Parking Slabs and Grade Beams

Many of the houses supported on pile foundations that the MAT visited had concrete slabs constructed at grade. These slabs were typically used as parking slabs beneath the elevated houses 

(Figure 3-123). Some of the slabs were thin (less than 4 inches thick); others were much thicker. Some had thickened edges and interior sections that acted as grade beams, presumably to 

stiffen the foundation. Virtually all slabs were reinforced with welded wire mesh and/or steel 

reinforcing bars.

Figure 3-123. 

Typical concrete parking 

slab beneath a pilesupported house (Bolivar 

Peninsula, TX) 

Figure 3-124. 

Undermining of concrete 

slab that settled 

but remained intact 

(Galveston Island, TX)
3-88 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

Where the piles were thought to be less well embedded, failure of the slab could have caused 

the pile foundation to rotate or rack (Figure 3-126). The MAT believes this was more common 

with older houses, and was likely a result of portions of the slab causing eccentric loads on the 

piles and the transfer of flood forces from the slab to the foundation.

The MAT observed instances where the weight of the slab likely contributed to foundation failure and building settlement, illustrated in Figures 3-127 and 3-128. Figure 3-127 shows a Holly 

Beach, LA, house under construction at the time of Ike. The piles and elevated floor beams had 

been placed, and a thick slab had been cast; when Ike undermined part of the slab, it cracked 

and settled, pulling some of the piles and beams downward. Figure 3-128 shows a house at Surfside Beach, TX, that was subject to considerable scour and erosion—when the slab settled and 

collapsed, it could have pulled part of the house lower as it went. Pile embedment appears to 

have been the larger issue at the houses shown in Figures 3-127 and 3-128, and insufficient embedment likely allowed the slabs to induce or worsen building settlement.

Figure 3-125. 

Pile-founded house 

with a slab thickened to 

create grade beams. The 

unthickened portion of 

the slab collapsed when 

undermined (Galveston 

Island, TX).
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PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly 3

Figure 3-126. 

Slab failure probably 

contributed to foundation 

damage (West Galveston 

Island, TX)

PHoTo couRTESy oF

STuART ADAMS, LSu

HuRRIcANE cENTER

Figure 3-127. 

Slab undermining and 

settlement during Ike 

probably pulled piles 

downward. Inset shows 

that the dropped piles also 

caused the floor beam to 

deflect (Holly Beach, LA).
3-90 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

The MAT observed several houses on Galveston Island where parking slabs were constructed 

in 4-foot square sections and unreinforced. This method of construction is consistent with that 

recommended in FEMA 55, Third Edition. Where these slabs were observed, their failure did 

not appear to adversely affect foundations or elevated buildings (Figure 3-129). Section III of 

the Galveston County Dune Protection and Beach Access Plan (2006) requires use of unreinforced 

fibercrete or concrete slab sections (maximum 4-inch thickness) within 200 feet of the vegetation line in eroding areas.

Figure 3-128. 

The weight of this slab, 

undermined due to scour 

and erosion, could have 

contributed to settlement 

and racking of this 

elevated house (Surfside 

Beach, TX)

Figure 3-129. 

Thin, unreinforced parking 

slab sections separated 

when undermined and 

collapsed in place, with 

no apparent adverse 

impact to the foundation 

(Galveston Island, TX)
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 3-91

Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family 3

3.3.4 Mold and Contamination

Hurricanes introduce various forms of contaminants and pollution into floodwaters and flooded buildings. Hurricanes also lead to the post-event growth of mold in wind- and flood-damaged 

buildings. Figure 3-130 illustrates one of many examples of mold and mildew growth observed 

by the Ike MAT. Guidance on cleanup and restoration of flooded buildings can be found in the 

Hurricane Katrina Recovery Advisory 2, Initial Restoration for Flooded Buildings (July 2006d), and 

Katrina Recovery Advisory 4, The ABCs of Returning to Flooded Buildings (July 2006e).

Figure 3-130. 

Mildew and mold forming 

on wall sheathing 

following flooding (Golden 

Meadow, LA)

3.3.5 Other Issues and Problems

The MAT observed other construction deficiencies and community enforcement problems. 

While the details of these particular deficiencies are not known, their existence indicates potential compliance issues that should be monitored and addressed in communities visited by 

the MAT. Figure 3-131 shows a case where floor beams and joists were improperly notched to 

allow for plumbing installation. This practice can weaken structural members and should only 

be done at the direction of a structural engineer. Figure 3-132 shows a case where flood vents 

did not penetrate through the entire enclosure wall—if this installation was complete when observed by the MAT, this practice is a clear violation of NFIP flood opening requirements.
3-92 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

3 PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly

3.4 Manufactured Housing

The MAT visited several communities in south Louisiana and east Texas where large numbers 

of manufactured homes were damaged by some combination of storm surge, waves, floodborne 

debris, and wind. In some locations in southwest Louisiana, manufactured housing installed 

after Hurricane Rita was not elevated to or above the BFE. This may have occurred in existing 

manufactured housing parks where an NFIP exception allows some homes to be elevated 3 feet 

above grade, even where this is lower than the BFE, or it may have occurred through incorrect 

Figure 3-131. 

Floor joists and beams 

were notched to allow 

for plumbing (Sulphur, 

Calcasieu Parish, LA)

Figure 3-132. Flood vent openings (red circles) that do not extend through the walls (Hackberry, Cameron Parish, 

LA)
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 3-93

Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family 3

application of the 3-foot exception. Whether this practice was allowed by the NFIP exception or 

not, the result was the same—large numbers of manufactured homes installed below the BFE 

after Hurricane Rita were heavily damaged or destroyed by Hurricane Ike.

3.4.1 Texas

In San Leon, TX, the MAT observed a manufactured home that was knocked off its foundation 

and destroyed. The home was located in a Zone AE (BFE = 11 feet) approximately 150 feet landward of a rip-rapped shoreline. High water marks in the area indicated water levels were over 12 

feet NGVD, and 5 feet or more above grade. Coastal A Zone conditions (wave heights between 

11⁄2 and 3 feet) likely existed there during Ike. 

The home, shown in Figure 3-133, was placed on short, unreinforced and un-mortared “dry 

stack” masonry piers placed on pre-cast concrete pads (at 8-foot centers [+/-]), and was secured 

with ground anchors spaced at 4-foot centers (+/-) with metal stabilizer plates.

Figure 3-133. Destroyed manufactured home (San Leon, TX) 

Source: Google Maps for inset showing location

Evidence suggests that the home was displaced from its piers by moving floodwaters or waves. 

Scour, undermining the concrete pads beneath the piers, may have contributed. Ground anchor failures were not noted, but the straps connecting the home to the anchors had torn away 

from the house’s anchorage points (Figure 3-134). HUD’s 2007 Manufactured Home Construction 

and Safety Standard (MHCSS), 24 CFR Parts 3280 and 3285, place this site in a Wind Zone II. The 

MHCSS requires Wind Zone II homes to be secured and anchored to their steel frames and to 

wall ties. No wall ties were observed. This suggests that the home was either non-compliant or 

was installed before the HUD standards went into effect.
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3 PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly

In Oak Island, TX, some manufactured homes were elevated on timber piles. The elevation prevented foundation failure, but some of the homes were still damaged by inundation 

(Figure 3-135).

Figure 3-134. 

Scour depressions existed 

around the masonry piers, 

pads, and ground anchor 

stabilizer plates (San Leon, 

TX)

Figure 3-135. 

Manufactured home in 

Oak Island, TX. The house 

foundation did not fail, 

but the elevation was 

insufficient to prevent 

damage from inundation.
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 3-95

Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family 3

3.4.2 Louisiana

The MAT observed that Zone A manufactured homes elevated at or above the BFE/ABFE on 

reinforced concrete or reinforced masonry piers with proper anchoring performed well. The 

best performance of foundations in Zone V was found to be timber piles embedded sufficiently 

to withstand erosion and scour effects. Zone V homes on piers resting on concrete pads often 

failed due to flood and erosion/scour effects. 

3.4.2.1 Cameron and Vermilion Parishes

Many of the manufactured homes that were present in Cameron and Vermilion Parishes in 

2005 are no longer in place. Those structures were destroyed by Hurricane Rita and in many 

instances, had not been replaced. Many of those that had been replaced after Rita and not elevated to or above the BFE/ABFE were damaged by Ike.

The manufactured homes shown in Figure 3-136 are located immediately east of the Cameron 

Parish offices along LA Hwy 82 in South Cameron. They are currently located within Zone A, 

but will be classified as Zone V when the pending new flood maps are adopted. The homes were 

not properly anchored and were forced off their foundation piers by the storm surge.

Figure 3-136. 

Two manufactured homes 

in Cameron, LA. Homes 

were displaced off 

foundations and siding 

peeled due to inundation 

and storm surge of 

approximately 4 feet 

above ground. 

3.4.2.2 Jefferson Parish

The manufactured home shown in Figures 3-137 and 3-138 is located in Zone A (BFE = 10 feet, 

ABFE = 12 feet) on Grand Isle, Jefferson Parish. Ike floodwaters were approximately 6 feet 

deep and did not reach the home, which was elevated in compliance with NFIP requirements. 

Support framing was in place, and strapping secured the walls and the steel chassis frame to 

the foundation. While effective during Ike, the strapping was installed using non-conventional 

methods. Its ability to resist a design wind event could not be determined. 
3-96 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

The home experienced some wind damage (vinyl siding and portions of the roof covering were 

dislodged) despite the fact that the Ike wind speeds and wind pressures were far below the HUD 

and ASCE 7-05 design wind speeds and pressures. Section 305 of the MHCSS, 24 CFR Part 3280, 

requires that siding be designed to resist wind loads for Exposure C specified in ANSI/ASCE 

7-88, or wind pressures specified the HUD Standard table titled Table of Design Wind Pressures. The MHCSS places Jefferson Parish in HUD Wind Zone III, and the Table of Design Wind 

Pressures requires exterior coverings within 3 feet of corners to resist +/- 58 psf, and exterior 

coverings in other areas to resist +/- 46 psf. The ASCE 7-05 wind pressures (for a 150 mph basic 

wind speed) are +49/-65.7 psf at the corners of a building and +49/-53.1 psf in other areas.

Figure 3-137. 

This elevated 

manufactured home in 

Grand Isle of Jefferson 

Parish, LA, had siding and 

roof damage, but did not 

move from its foundation

Figure 3-138. 

The framing and anchoring 

system of the house 

shown in Figure 3-137. 

Strapping secured the 

home’s walls and frames 

to its foundation. While the 

strapping held the home to 

its foundation during Ike, 

it could not be determined 

if the strapping would 

resist a design wind event 

(Estimated wind speed 

during Ike: less than 60 

mph, 3-second gust).
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PERfORMANcE Of RESIdENTIAl BuIldINGS (flOOd ANd WINd), ONE- TO TWO-fAMIly ANd MulTI-fAMIly 3

3.4.2.3 Lafourche Parish

The Zone A home shown in Figure 3-139 in Lafourche Parish was elevated, but not above the 

BFE. It suffered flood damage from about 3 to 4 feet of water above the floor. Interviews with 

nearby residents indicated the floodwaters reached the eaves on the house with the green roof 

to the right. Flood velocities were not sufficient to shift the manufactured home off of its foundation and the floodwaters rose slowly enough to allow leakage into the home, thereby preventing 

the home from becoming buoyant and floating off its foundation.

Figure 3-139. 

Zone A manufactured 

home in the Golden 

Meadows section of 

Lafourche Parish, LA, 

sustained 3 to 4 feet of 

flooding above the floor, 

but did not shift or float 

off of its foundation. The 

red arrow indicates the 

flood level reported by 

neighbors.

3.4.2.4 Manufactured Home Anchoring and Support Systems

Manufactured homes in SFHAs must be placed on foundation systems that will resist flotation, collapse, and lateral movement (Figure 3-140). The 2005 edition of the NFPA 225, Model 

Manufactured Home Installation Standard, contains performance requirements for flood-resistant 

manufactured home installations. The 2008 edition, issued in January 2009, also contains 

prescriptive flood-resistant installations. Other flood-resistant foundation solutions will be contained in the revised FEMA 85, scheduled to be completed in 2009.
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3 Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family

3.5 Mitigation Projects

The MAT typically looks at funded mitigation projects to determine if the projects were successful. The MAT visited 27 residential mitigation projects in Louisiana and 10 in Texas. Thirty-four 

of the projects visited were elevation projects, and three were acquisition projects. All of the 

projects received funds through the Hazard Mitigation Grant Program (HMGP) or through 

Increased Cost of Compliance payments via NFIP flood insurance policies. There were no structures visible at the three acquisition project sites, and the land had been cleared and restored. 

Three of the 34 elevation projects had not been undertaken at the time of the MAT visit. The remaining 31 elevation projects had been completed and were successful as far as preventing Ike 

flood damage—none of the elevated buildings appeared to have been flooded during Ike, even 

though many of the building sites were inundated. Most of the buildings had been elevated on 

masonry piers, tall masonry columns, or timber piles. 

While most of the elevation projects appeared to have been constructed in accordance with 

applicable codes and standards, some load path deficiencies (Figure 3-141) were noted that indicate possible project design and/or compliance problems that should be investigated. Some 

of the elevated buildings sustained wind damage to the building envelope during Ike (Figure 

3-142); this is likely a result of older homes being elevated, as opposed to a problem with the 

elevation project itself.

Figure 3-140. 

Prescriptive FloodResistant Foundation 

Design 
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 3-99

Performance of Residential Buildings (Flood and Wind), One- to Two-Family and Multi-Family 3

Figure 3-141. 

Zone A house elevated 

with Increased Cost of 

Compliance funds on 

masonry piers (Iberia 

Parish, LA). There was 

no evidence of pier 

reinforcement, mortar 

between masonry blocks, 

or ties between the piers 

and the elevated home.

Figure 3-142. 

House elevated with 

Increased Cost of 

Compliance funds (Kemah, 

TX). Inset shows evidence 

of wind damage to roof 

(Hurricane Ike estimated 

wind speed in this area: 

90 mph, Exposure B).

HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 4-1

PERFORMANCE OF CRITICAL FACILITIES 4

Performance of Critical 

Facilities

Critical facilities are important before, during, and after natural 

hazard events. They are needed to prepare for an event, house 

emergency workers during an event, and manage response and 

recovery operations after an event. Hurricane Ike had a significant 

impact on many of these facilities, totally destroying some of them and 

severely interrupting the operations of several others.

Several of the observed facilities were damaged by flooding, and many experienced wind damage, even though they were subjected to winds that were below current design wind speeds. 

Most critical facilities did not perform any better than commercial buildings. The poor building 

performance placed additional burdens on response and recovery personnel as they endeavored to provide assistance to their communities after the event.

Critical facilities are Category III and IV buildings as defined in ASCE 7-05 and the 2006 IBC 

(Section 1604, General Design Requirements, Table 1604.5). Category III and IV buildings 

4Performance of Critical 

Tom Smith 

David Conrad

Dave Low

Mark Matulik

Wallace Wilson
4-2 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

4 PERFORMANCE OF CRITICAL FACILITIES

include, but are not limited to, hospitals and other medical facilities, fire and police stations, 

primary communications facilities, EOCs, schools, shelters, and power stations and other facilities required in an emergency. In addition to the buildings listed in Categories III and IV, other 

buildings can play vital roles in recovery after an event, such as buildings used to provide housing for emergency workers. 

Buildings that sustained damage from flooding may not have been elevated enough to reduce 

damage from the flood levels experienced. Most of the wind damage was to envelope systems 

and rooftop equipment. Except for occasional shuttering of glazed openings, most of the investigated buildings did not appear to have been designed and constructed with wind-resistant 

enhancements to the building envelope and rooftop equipment.

Table 4-1 lists the type and total number of critical facilities that were observed by the MAT. Sections 4.1 through 4.4 describe the performance of some of these critical facilities. 

Table 4-1. Critical Facilities Observed by the MAT

Facility Type

Louisiana Texas

Total Number of Facilities 

Observed by MAT

Exposed 

to flood 

and wind*

Exposed 

to wind 

only**

Exposed 

to flood 

and wind

Schools/shelters (Section 4.1) 2 3 4 9

Hospitals/healthcare (Section 4.2) 2 4 1 7

Police, Fire, EOC (Section 4.3) 5 7 6 18

Government Buildings (Section 4.4) 2 6 6 14

* In portions of Louisiana, critical facilities experienced relatively low wind speeds (e.g., 50 mph or less).

** Critical facilities observed in Texas experienced wind speeds of 90 mph or greater (peak gust, Exposure C, 33 feet 

above grade).

Special Flood-Related Provisions for Critical Facilities

The 2006 edition of the IBC requires Category III and IV buildings to be designed and constructed in accordance with ASCE 24-05, which calls for these buildings to be elevated above 

the NFIP minimum elevation requirement. ASCE 24-05 elevation provisions are summarized in 

Table 4-2 (refer also to Section 2.2).

States and communities often impose their own freeboard requirements on critical facility construction in flood hazard areas. For example, Pennsylvania requires special permits and requires 

at least 1.5 feet of freeboard (Commonwealth of Pennsylvania, 2001). Louisiana encourages the 

addition of 1 foot of freeboard for projects receiving State funds. 
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 4-3

PERFORMANCE OF CRITICAL FACILITIES 4

Under Executive Order 11988,1 Floodplain Management, Federal agencies undertaking actions (funding, permitting, constructing, etc.) affecting critical facilities are to avoid the 

0.2-percent-annual-chance (500 year) floodplain. If that is not possible, Federal agencies are 

to protect (elevation or floodproofing) critical facilities to the 0.2-percent-annual-chance 

(500-year) flood level. 

Table 4-2. ASCE 24-05 Elevation Requirements for Critical Facilities 

Building 

Component

Category III Category IV

Zone A Zone V and 

Coastal A Zone* Zone A Zone V and 

Coastal A Zone*

Lowest Floor 

Elevation**

BFE + 1 foot, or 

DFE, whichever is 

higher

BFE + 1 or 2 feet**, 

or DFE, whichever 

is higher

BFE + 2 feet, or 

DFE, whichever 

is higher

BFE + 1 or 2 feet**, 

or DFE, whichever 

is higher

DryFloodproofing

BFE + 1 foot, or 

DFE, whichever is 

higher

Not allowed

BFE + 2 feet, or 

DFE, whichever 

is higher

Not allowed

FloodDamage 

Resistant 

Materials

BFE + 1 foot, or 

DFE, whichever is 

higher

BFE + 2 or 3 feet**, 

or DFE, whichever 

is higher

BFE + 2 feet, or 

DFE, whichever 

is higher

BFE + 2 or 3 feet**, 

or DFE, whichever 

is higher

Utilities and 

Equipment 

Elevation

BFE + 1 foot, or 

DFE, whichever is 

higher

BFE + 2 or 3 feet**, 

or DFE, whichever 

is higher

BFE + 2 feet, or 

DFE, whichever 

is higher

BFE + 2 or 3 feet**, 

or DFE, whichever 

is higher

BFE = base flood elevations; DFE = design flood elevation

* Coastal A Zone is the area subject to wave heights of 1.5 to 2.9 feet during the base flood; on newer FIRMs it will be 

the area between the LiMWA (limit of moderate wave action) and Zone V.

** Lowest floor elevation = top of lowest floor (walking surface) in Zone A, and bottom of lowest horizontal structural 

member supporting the lowest floor in Zone V and Coastal A Zone.

Special Wind-Related Provisions for Critical Facilities

The 2006 edition of the IBC has only two special wind-related provisions pertaining to Category 

III and IV buildings:

n Importance factor: The importance factor for these buildings is 1.15, rather than the 1.0 

factor that is used for most other types of buildings. Using the 1.15 importance factor 

effectively increases the design loads for the MWFRS and C&C by 15 percent. 

n Windborne debris loads: For buildings located within windborne debris regions (as defined 

in ASCE 7-05) of hurricane-prone regions, exterior glazing is required to be impactresistant. For Category III and IV buildings located where the basic wind speed is 130 mph 

or greater, the glazing is required to resist a larger momentum missile load than the glazing 

on other types of buildings.

1 http://www.fema.gov/plan/ehp/ehplaws/eo11988.shtm
4-4 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

4 PERFORMANCE OF CRITICAL FACILITIES

4.1 Schools/Shelters

In addition to their traditional role as educational facilities, schools often play an important role in 

providing space for sheltering, emergency response, and recovery after a hurricane. Thus, their loss 

of use can greatly affect a community’s ability to rapidly respond to the needs of disaster victims. 

4.1.1 Crenshaw Elementary and Middle School (Port Bolivar, TX)

The Crenshaw Elementary and Middle School in Port Bolivar, TX, opened in 2005 (Figures 4-1 and 

4-2). The school is located approximately 2,400 feet inland of the Gulf shoreline. It is elevated on 

concrete columns, with the bottom of the first floor beams approximately 10 feet above grade. 

The facility did not suffer flood damage because of its elevated construction, but considerable 

floodborne debris washed underneath the school (Figure 4-3). A debris line on a fence under the 

school indicated the flood depth was approximately 5.5 feet above grade; a debris line on a fence 

adjacent to the school was surveyed and found to be at elevation 14.8 feet NAVD (URS, 2008). 

The school received some wind damage to its roof and rooftop equipment. The gym roof deck 

is cementitious woodfiber. Other roof deck areas are steel. According to ASCE 7-05, the basic 

(design) wind speed for this location is approximately 130 mph. The estimated maximum wind 

speed during Hurricane Ike was approximately 110 mph.2

General Wind Damage. The building suffered some wind damage to its roof, as a result of the gutter blowing off the roof and damage to rooftop equipment, described below. 

2 All estimated speeds in this Chapter are peak gust, Exposure C, at 33 feet taken from Estimates of Maximum Wind Speed 

Produced by Hurricane Ike in Texas and Louisiana (ARA, 2008).

Figure 4-1. 

September 19, 2008, 

aerial view of Crenshaw 

Elementary and Middle 

School 
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 4-5

PERFORMANCE OF CRITICAL FACILITIES 4

The gutter and most of its brackets blew off the gym roof (Figure 4-4), but the roof membrane 

did not progressively peel as is typically the case when a gutter is blown away. The brackets were 

attached with two ring-shank nails, both of which were located near the top of the bracket, as 

shown in the inset in Figure 4-4. Since both fasteners were near the top of the bracket, they provided little resistance to outward rotation (moment) as the wind pulled and lifted the gutter 

away from the building. Significant permanent outward deformation was observed at gutters at 

other roof areas of the building (similar to the condition shown by the inset at Figure 4-41). To 

resist the moment force, a screw should have been placed near the lower edge of the bracket, as 

shown by the red line in the inset at Figure 4-4. Screws should be used to attach brackets because 

they are more resistant than nails to dynamically induced pull-out forces. The gutter brackets 

were not attached to the gutter (see discussion in Section 4.3.2).

Figure 4-2. 

General view of Crenshaw 

Elementary and Middle 

School 

Figure 4-3. 

Wall of house washed 

underneath Crenshaw 

School during Ike (note 

shutters still attached to 

wall) 
4-6 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

4 PERFORMANCE OF CRITICAL FACILITIES

The MAT observed the rooftop equipment on the facility. The rooftop exhaust fans had too 

few fasteners, although none of the fans blew away during this storm. The exhaust fans were attached with two screws per side; for this location, FEMA 543, Design Guide for Improving Critical 

Facility Safety from Flooding and High Winds: Providing Protection to People and Buildings (2007), 

recommends six screws per side. The hood blew off two units, which allowed rain to enter the 

building (Figure 4-5). 

Access panels blew off a few pieces of rooftop equipment. As shown in Figure 4-6, rain was able 

to directly enter the building during the storm and was still able to at the time of the MAT visit. 

The ductwork shown in Figure 4-6 was easy to shake back and forth by hand (illustrated by the 

double-headed red arrow). Had the winds been near design conditions, the ductwork may have 

blown away. 

Functional Loss. The school was closed after Ike but served as a location for emergency operations and many community meetings during the post-Ike response and recovery period. At the 

time of the MAT investigation, the building was being used to house fire department personnel 

from other areas in Texas. These personnel provided emergency services for those involved in 

recovery efforts. 

Figure 4-4. 

Location where the gutter 

blew off the gym roof; 

gutter bracket shown at 

inset 
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 4-7

PERFORMANCE OF CRITICAL FACILITIES 4

Although some water infiltrated damaged rooftop equipment, the storm’s impact on this facility’s functioning as a critical facility was minimal. The school reopened in February 2009 when 

some students were able to return to the school. 

Vulnerabilities and Other Observations. Had the winds been stronger, significant water infiltration 

would have been likely due to roof membrane blow-off associated with gutter failure. 

Figure 4-5. 

Wind blew off the hood, 

allowing rain to directly 

enter the building 

Figure 4-6. 

Missing access panel 

allowed rain intrusion; 

ductwork could be easily 

flexed 
4-8 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

4 PERFORMANCE OF CRITICAL FACILITIES

4.1.2 South Cameron Parish High School (Grand Chenier, LA)

The South Cameron Parish High School located in Grand Chenier, LA, received significant 

damage from flooding during Hurricane Ike. The school is located on Grand Chenier Highway 

and is approximately 2.1 miles from the Gulf of Mexico shoreline. The facility had been previously damaged by flooding during Hurricane Rita, including extensive damage to the school 

and gymnasium. Although repairs and reconstruction were still in progress when Ike hit, facility 

personnel stated that the damages observed by the MAT were caused by Ike. However, no mitigation for flooding had been performed and the facility was not elevated.

The school complex is comprised of two flood zones. The southern portion is located in flood 

hazard Zone AE (BFE = 12 feet NGVD); the northern portion is located in Zone VE (BFE = 

12 feet NVGD). In March 2006, FEMA published ABFE Maps showing the southern portion as 

Zone AE (ABFE = 13 feet NGVD) and the northern portion as Zone VE (ABFE = 13 feet NGVD). 

The March 2008 Preliminary DFIRM, released by FEMA after completion of the post-Katrina 

and Rita flood hazard studies, shows the entire site will be remapped as Zone VE (Coastal High 

Hazard Areas) with a BFE of 15 feet. The gymnasium and track and the modular units are all in 

the northern portion. 

General Flood Damage. The interiors of all the buildings were flooded. A debris line on the fence 

at the front of the school indicated flood depths reached approximately 5 feet above grade. 

The wooden gymnasium floor was damaged, and metal walls seaward of the gymnasium were 

breached by flooding. Approximately 15 modular classrooms were inundated by storm surge 

floodwaters (Figures 4-7 and 4-8). At the time the MAT inspected the school, students had been 

relocated to other schools in the Parish.

General Wind Damage. The MAT did not access the roof at this facility, so a determination of wind 

damage could not be made.

Figure 4-7. 

Damage to South Cameron 

Parish School modular 

units
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 4-9

PERFORMANCE OF CRITICAL FACILITIES 4

Functional Loss. The South Cameron Parish School suffered a complete loss of function. The 

school experienced storm surge inundation. The school was not operational at the time of the 

MAT’s visit. 

4.1.3 Johnson’s Bayou School (Cameron, LA)

The Johnson’s Bayou School, grades K–12, suffered significant flood damage during Hurricane 

Ike. Like South Cameron High School, this critical facility is located on Gulf Beach Highway 

and is approximately 1.3 miles from the Gulf of Mexico shoreline. 

General Flood Damage. The facility was flooded by storm surge with depths reaching 5 to 6 feet. 

Some masonry walls were flood damaged, as were interior walls, furnishings, and electrical systems (Figures 4-9 through 4-12). 

Figure 4-8. 

High school gymnasium 

at South Cameron Parish 

School

Figure 4-9. 

Johnson’s Bayou School 

interior building damage 
4-10 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

4 PERFORMANCE OF CRITICAL FACILITIES

Figure 4-10. 

Johnson’s Bayou School – 

damage to wall on front 

side of facility (soffit of 

driveway canopy was also 

damaged) 

Figure 4-11. 

Johnson’s Bayou School gymnasium interior 

damage 
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 4-11

PERFORMANCE OF CRITICAL FACILITIES 4

Figure 4-12. 

Johnson’s Bayou School CMU wall collapse. 

(Note: HVAC units that had previously been 

damaged were relocated to an elevated 

platform under the FEMA Public Assistance 

Program.) 

General Wind Damage. Significant wind damage occurred to the roof system for the school gymnasium (Figure 4-13). Figure 4-13 also shows the significant damage to the walkway canopy. The 

Johnson’s Bayou School experienced damage to roof coverings and rooftop equipment. The 

breached building envelopes allowed widespread rainwater damage and storm surge floodwater 

intrusion to the interior. 

Functional Loss. The combination of storm surge flooding to depths reaching 5 to 6 feet with 

widespread rainwater damage from the breached building envelope resulted in the loss of 

school operations. At the time of the MAT inspection, the school was not operational.
4-12 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

4 PERFORMANCE OF CRITICAL FACILITIES

Figure 4-13. 

Johnson’s Bayou 

School gymnasium. The 

red ovals indicate damage 

to canopy and roof.

4.2 Hospitals/Health Centers

When a hurricane strikes, hospitals and health centers, EOCs, and shelters are the most important buildings in a community. In addition to providing continuity of care for patients in 

hospitals before a storm, hospitals also receive large numbers of people seeking medical treatment after strong hurricanes. Blunt-force trauma injuries caused by windborne debris, falling 

trees, collapsed ceilings, partial building collapse, and flood-related injuries occur during hurricanes; however, most hurricane-related injuries typically occur in the days afterward. These 

injuries are typically due to chainsaw accidents, stepping on nails, lacerations incurred while 

removing debris, vehicle accidents at intersections that no longer have functional traffic lights, 

people falling off roofs as they attempt to make emergency repairs, and carbon monoxide poisoning or electrical shock from improper use of emergency generators. Therefore, at a time 

when many hospitals in an area may be functionally impaired or no longer capable of providing 

service due to building damage, hospital staffs are faced with a higher than normal number of 

people seeking treatment. Before arrival of a hurricane, hospitals also often admit an influx of 

women in their third trimester of pregnancy who wish to be at the hospital in case they go into 

labor during the storm or shortly thereafter, when getting to the hospital could be hazardous 

or impossible.

4.2.1 San Jacinto Methodist Hospital (Baytown, TX)

The San Jacinto Methodist Hospital in Baytown, TX, was constructed around 1974, and a medical office building was added in 1995. The hospital sustained some wind and water leakage 

damage during Hurricane Ike. According to ASCE 7-05, the basic wind speed for this location 
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 4-13

PERFORMANCE OF CRITICAL FACILITIES 4

is approximately 113 mph. The estimated maximum wind speed during Hurricane Ike was approximately 105 mph. Figure 4-14 is a general view of the building. The facility was evacuated 

on September 11, 2008, because of a mandatory evacuation order. The facility was reoccupied 

on September 18, 2008. 

In the aftermath of Tropical Storm Allison (2001), mitigation work was performed on the facility 

in 2003–2004 using HMGP grant funds. The work included reroofing the medical office building 

and a portion of the hospital. The roof that was replaced at the office building was a modified bitumen membrane. The roof that was replaced at the hospital was an aggregate-ballasted, 

single-ply membrane. Mineral surface modified bitumen membranes over rigid insulation were 

used for the mitigation work. Both of these roof areas have steel roof decks. According to project records, the new roofs had a Factory Mutual Global 1-90 rating (i.e., the roof system was 

sufficient for field of roof design pressures up to 45 psf). (Note: The field design uplift load 

is approximately 30 psf, hence the specified system had sufficient uplift resistance to meet the 

ASCE 7-02 load.) 

General Wind Damage. The facility experienced some water leakage at the three-story wing shown 

in Figure 4-14. Some of this leakage was likely due to damaged rooftop equipment. The MAT 

observation of the roof on this portion of the facility indicated that at least one fan cowling was 

blown away. No special attachment was provided for the fan cowlings (such as that shown in 

FEMA 577, Design Guide for Improving Hospital Safety in Earthquakes, Floods, and High Winds: Providing Protection to People and Buildings [2007]). However, special attachment was provided for 

the condenser shown in Figure 4-15. Strapping condensers is a practice that is recommended in 

FEMA 543 and 577. Unless strapped, condensers frequently topple over. 

Figure 4-14. 

General view of San 

Jacinto Methodist Hospital
4-14 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

4 PERFORMANCE OF CRITICAL FACILITIES

In a few areas, the lightning protection system (LPS) conductors became detached from the 

roof membrane (Figure 4-16). Loose conductors can puncture and tear roof membranes, and 

they no longer provide the intended protection. FEMA 543 and 577 provide guidance for attachment of LPSs to resist wind. 

Figure 4-15. 

Condenser with tie-down 

cables 

Figure 4-16. 

Detached LPS conductor
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 4-15

PERFORMANCE OF CRITICAL FACILITIES 4

The satellite dish shown in Figure 4-17 was held down only with CMU. This attachment technique was adequate for the winds experienced at this site, but dishes attached by this method 

have failed in other hurricanes, as shown in the inset at Figure 4-17. The dish shown in the 

inset was blown completely off the roof; only the CMU remained (FEMA 488).

Figure 4-17. 

This satellite dish was 

held down with CMU 

only; inset shows all that 

remains from a similarly 

mounted dish after a 

strong hurricane

Functional Loss. Water infiltration resulted in some damage to interior finishes, and the leakage 

disrupted use of some rooms. However, the disruption did not adversely affect delivery of services. It cost approximately $60,000 to repair the damages. For approximately 3 weeks after the 

facility was reoccupied, the facility’s emergency generator provided power during intermittent 

municipal power outages. There was no interruption of water or sewer service.

Vulnerabilities and Other Observations. At the two mitigated roofs and the other non-mitigated 

roofs, had the winds been stronger, extensive damage to rooftop equipment and significant 
4-16 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

4 PERFORMANCE OF CRITICAL FACILITIES

water infiltration would have been likely due to 

equipment blow-off and roof membrane punctures associated with rooftop equipment failures 

and detached lightning protection equipment. 

Also, had the winds been stronger, depending 

upon wind direction, glazing damage would have 

been likely from windborne debris comprised of 

tree branches near the facility and/or aggregate 

from a built-up roof (BUR) on a building near 

the hospital campus. 

Additionally, had the winds been stronger, portions of the exterior insulation finish system 

(EIFS) wall covering may have blown away or 

been penetrated by windborne debris. EIFS wall 

covering failures are commonplace during hurricanes. This wall covering system can offer good 

high-wind performance, but great attention to design and application is needed to do so. FEMA 

577 does not recommend this type of wall covering on hospitals in hurricane-prone regions.

The MAT also observed a lack of adequate pre-storm preparations. As part of the pre-storm preparations, hospital roof areas should be checked. As part of this check, roof drains, scuppers, and 

gutters should be cleaned of debris so that they are capable of draining the roof during the hurricane (some of which produce a tremendous quantity of rain). Figure 4-18 is a view of one of the 

mitigated roofs. Clearly this roof drain area had not been cleared of debris for quite some time.

Performance of HMGP Mitigation Work. When the facility undertook mitigation work, conducting 

a comprehensive vulnerability assessment and then mitigating the significant vulnerabilities, 

or alternatively, recognizing the residual risk that remains, would have been prudent (see 

FEMA 577).

Replacing the aggregate-surfaced roof was appropriate, because aggregate can be blown off 

and damage glazing or injure people that come to the hospital during a hurricane. However, 

the mitigation work was not as robust as it should have been. Although the roof membrane 

choice was appropriate (and one that is recommended in FEMA 577) and had adequate uplift resistance, the new roofs did not incorporate secondary membranes to avoid water leakage 

in the event the membranes were punctured by 

windborne debris. In addition, as previously described, much of the rooftop equipment was not 

adequately anchored, including fan cowlings, 

fans, some heating, ventillation, and air-conditioning (HVAC) units, condensate drain lines, 

and the LPS. 

In addition to the inadequacies of the mitigation 

work that was performed, the mitigation work 

Glazing protection: Since this building is 

not in a windborne debris region, glazing 

protection is not required. However, debris-induced glazing damage has been 

documented to have occurred during wind 

speeds slightly in excess of 100 mph (peak 

gust at 33 feet, Exposure C). Accordingly, 

in hurricane-prone regions, FEMA 543 and 

577 recommend glazing protection when 

the basic wind speed is 100 mph or greater. 

Providing glazing protection at this facility 

as part of the mitigation work would have 

been prudent.

Inadequate fan anchorage: One of the 

2-foot by 2-foot exhaust fans was attached 

with two screws per side, but for this location, FEMA 577 recommends four screws 

per side. One of the 3-foot by 3-foot fans 

had three screws per side, but for this size 

of fan, FEMA 577 recommends five screws 

per side. 
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 4-17

PERFORMANCE OF CRITICAL FACILITIES 4

only addressed a portion of the hospital. Other roofs and rooftop equipment had (and still 

have) significant wind vulnerabilities. Before implementing a mitigation project, a comprehensive vulnerability assessment should be conducted to identify significant vulnerabilities. If funds 

are not available to correct all identified deficiencies, the work should be systematically prioritized so that the items of greatest need are corrected first. Following this process also allows the 

building owner to be aware of residual risks that remain when mitigation projects don’t address 

all significant vulnerabilities at a facility. For further information about mitigating existing facilities, see FEMA 577, Section 4.4.

Figure 4-18. 

View of one of the 

mitigated roofs. Note 

the vegetation growth 

in the vicinity of the roof 

drain, indicating a lack of 

maintenance.

4.2.2 Winnie Community Hospital (Winnie, TX)

The Winnie Community Hospital, constructed in the late 1960s, received wind damage during 

Hurricane Ike. According to ASCE 7-05, the basic wind speed for this location is approximately 

119 mph. The estimated maximum wind speed during Hurricane Ike was approximately 108 

mph. Figure 4-19 shows a general view of the building. Because of flooding concerns, Chambers 

County issued a mandatory evacuation order for this hospital and other healthcare facilities 

around noon on September 11 (approximately 1 1⁄2 days before Hurricane Ike made landfall). 

The evacuation was accomplished within 2 hours, but was hampered by a lack of ambulances, 

which were also needed to evacuate hospitals in Beaumont and Galveston. The hospital reopened to offer limited urgent care 3 days after Ike’s landfall. 

General Wind Damage. An entry canopy blew away (Figure 4-19). A few windows were broken 

(likely by windborne debris) and wind-driven water entered at several of the windows. At one 

area, a portion of the edge flashing deformed outward and the nailer lifted, which caused a few 

of the bricks at the top course to fall. Had the winds been somewhat stronger, the edge flashing 

would likely have lifted and caused a portion of the roof membrane to blow away. 
4-18 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

4 PERFORMANCE OF CRITICAL FACILITIES

Numerous pieces of HVAC equipment were on the roof. Many condensers toppled, but apparently none punctured the single-ply roof membrane. However, water entered the building 

where some rooftop ductwork blew away (Figure 4-20). Access panels were blown away at a piece 

of equipment and the communications tower collapsed (both shown in Figure 4-21).

Figure 4-19. 

A Winnie Community 

Hospital entry canopy (red 

oval) blew away

Figure 4-20. 

Water entered the building 

where ductwork blew 

away
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 4-19

PERFORMANCE OF CRITICAL FACILITIES 4

Functional Loss. At the time the hospital was reoccupied, municipal power was out, so power 

was provided by the hospital’s emergency generator. After 2 days, the generator’s governor 

failed, leaving the hospital without power and unable to provide urgent care services. The 

generator failure caused a power surge, which damaged several pieces of hospital equipment 

(including refrigerators). This, in turn, resulted in the loss of vaccines, medications, lab reagents, and food. Equipment had to be retested to ensure that it was safe for use.

The facility had to be vacated for 4 days until a backup generator was delivered and connected. FEMA supplied the portable generator (inset at Figure 4-22) and the facility was able to 

reopen. Altogether, the facility ran on emergency power for about 2 weeks. During that time, 

the facility was periodically refueled. There was no interruption of water or sewer service.

Vulnerabilities and Other Observations. Had the winds been stronger, extensive damage to rooftop equipment and significant water infiltration would have been likely due to roof membrane 

blow-off and punctures associated with edge flashing and rooftop equipment failures. 

The generator was outdoors, with a roof and walls that were open at the top and bottom for 

air circulation (Figure 4-22). Although the generator was not damaged by wind or windborne 

debris in this event, the enclosure does not provide sufficient protection for the generator.

Figure 4-21. 

Collapsed communications 

tower and blown-away 

access panels (red circle) 
4-20 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

4 PERFORMANCE OF CRITICAL FACILITIES

4.2.3 University of Texas Medical Branch (Galveston, TX) 

The University of Texas Medical Branch (UTMB) 

in Galveston, TX, received significant flood damage and some wind damage. This teaching and 

research hospital complex has about 90 buildings on the main campus (a few of which are 

a few blocks from the fringes of the main campus). UTMB inhabitants were evacuated prior to 

the storm, including 260 patients, students, and 

staff. 

Approximately two-thirds of the facility is located 

in flood hazard Zone A (BFE = 11 feet NGVD), with 

the remaining buildings located in shaded Zone X (area between the 1-percent-annual-chance 

flood and the 0.2-percent-annual-chance flood) and Zone X (outside the 0.2-percent-annualchance flood area). A review of the UTMB Emergency Operations Plan map3

 shows that first 

floor elevations of campus buildings vary from approximately 7 to 16 feet NGVD. 

According to ASCE 7-05, the basic wind speed for this location is approximately 132 mph. The 

estimated maximum wind speed during Hurricane Ike was approximately 108 mph.

Figure 4-22. 

The emergency generator 

was housed within this 

shed; a portable generator 

(inset) was brought to the 

site after the emergency 

generator failed 

As of January 2009, FEMA had obligated 

$73 million to repair the damaged facilities, 

replace equipment, and recover documents 

(www.fema.gov:80/news/newsrelease.

fema?id=47217). 

In addition to the devastation at UTMB and 

disruption of services, the temporary loss 

of jobs at the UTMB campus had a significant economic impact on the Galveston 

area.

3 http://www.utmb.edu/emergency%5Fplan/pdfs/Emergency%20Plan%20-%20rev%2013.pdf
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 4-21

PERFORMANCE OF CRITICAL FACILITIES 4

General Flood Damage. The Ike flood elevation in the vicinity of UTMB fluctuated above and 

below approximately 12.5 feet NGVD. A review of the Emergency Plan Map showed that approximately one-third of the campus buildings have first floor elevations greater than 12.5 feet 

NGVD, and virtually all buildings have subgrade areas for utilities and equipment. UTMB staff 

reported to the MAT that approximately 90 percent of the buildings were flooded during Hurricane Ike, and approximately 90 percent of the building damage was due to flooding.

Figures 4-23 through 4-26 show some of the water marks remaining and flood clean-up underway 

during the MAT visit on October 20, 2008. Flooding damaged utility lines and equipment, generators, HVAC equipment, pumps and controls, gas piping for hospital and operating rooms, 

the morgue, offices, laboratories, and classrooms.

Figure 4-23. 

High water mark (dashed blue line) shown 

from the outside of UTMB Building 1. The mark 

was measured by the MAT and found to be 

approximately 69 inches above the floor of the 

basement area inside the building. 
4-22 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

4 PERFORMANCE OF CRITICAL FACILITIES

Figure 4-24. 

Clean-up underway 

inside the basement of 

UTMB Building 1. All the 

laboratory equipment, 

office and classroom 

contents, and interior 

finishes had to be 

decontaminated and 

removed for disposal. 

Figure 4-25. 

The Ike flood level in 

UTMB Building 56 pump 

room was approximately 

30 inches above the 

floor, and controls and 

equipment were damaged 
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 4-23

PERFORMANCE OF CRITICAL FACILITIES 4

General Wind Damage. A preliminary condition assessment was conducted of the campus by a 

consultant (AESTIMO, INC., Facilities Engineering Consultants, Houston, TX) on September 

22 and 23, 2008, to assess damage to roofs, rooftop equipment, windows, and exterior walls. To 

expedite the assessment process, roofs on several buildings were observed from higher rooftops. 

Hence, some roof membrane punctures or other types of damage may not have been identified. The report, titled Preliminary Building Envelope Condition Assessment Report, dated September 

25, 2008, provided a list of priority buildings with 75 high priority repair items, summarized 

below:

n 16 buildings with broken windows (including skylights)

n 12 buildings with punctured roof membranes

n 2 buildings with roof membranes that blew off

n 5 buildings with roof system adhesion problems (i.e., the membrane did not blow off, but 

the insulation debonded from the deck or the membrane debonded from the insulation)

n 16 buildings with fan cowlings that blew off

n 29 buildings with fans or other rooftop equipment damage that resulted in water 

infiltration

n 15 buildings with flashing problems, including flashings at rooftop equipment (leakage 

occurred at a few flexible connectors between ducts and fans)

n 7 buildings with LPSs that detached from the roof

During their visit to UTMB in Galveston, the MAT observed the wind-induced damage described 

on the following page.

Figure 4-26. 

Replaced lower interior 

wall sections leading to 

UTMB Building 90 
4-24 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

4 PERFORMANCE OF CRITICAL FACILITIES

At the building shown in the inset of Figure 4-27, several penthouse wall panels were damaged. 

The panels consisted of inner and outer metal skins, with a foam insulation core. As shown in 

Figure 4-27, several of the outer skins blew away. The panels appeared to have been job-site 

fabricated, rather than having been produced as composite panels in a factory. The presence 

of the very high parapet prevented the metal skins from being blown from the roof and potentially damaging other parts of the facility as windborne debris. At another building, blown 

off EIFS was observed at a wall and at the soffits of an enclosed elevated walkway between two 

buildings.

Figure 4-27. 

A very high parapet kept 

the blown-off metal panels 

on the roof

At the time Hurricane Alicia struck this campus in 1983, many of the buildings had aggregatesurfaced BURs and several windows on the campus were broken by wind-blown aggregate. Since 

Alicia, when buildings have been reroofed, they were not replaced with aggregate surfacing. 

However, at the time of Hurricane Ike, some aggregate-surfaced BURs still existed, such as that 

shown in Figure 4-28. One of the penthouse roofs was blown off during the storm. At the time 

of the MAT observation, that roof had been replaced by the white membrane shown by the red 

arrow. 
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 4-25

PERFORMANCE OF CRITICAL FACILITIES 4

One of the reroofing designs used by the hospital consists of a modified bitumen membrane 

over gypsum roof board, over rigid insulation, over a modified bitumen sheet, over a concrete 

deck. This is one of the roof assembly types recommended in FEMA 577. In FEMA 577, the purpose of the secondary membrane (i.e., the one over the deck) is to prevent water from leaking 

into the building in the event a roof membrane is punctured or blown off. However, the roof 

designers for the UTMB reroofing work specified the secondary membrane to avoid leakage 

during the tear-off and replacement of the old roof and thus, the secondary membrane fulfilled 

two roles. 

Other rooftop equipment damage included a large stack that was blown over, even though it 

was guyed (Figure 4-29), and damage to two relief air hoods (Figure 4-30). One of these hoods 

blew off the curb. 

Nine of the 32 windows in the building shown in Figure 4-31 were broken. They were likely damaged by windborne debris. 

Functional Loss. The entire UTMB facility was closed following Ike. To provide emergency 

medical services, three portable operating rooms and a portable pharmacy were set up on the 

campus. Floors above the first floors of some buildings were re-opened starting in October 2008 

for limited office, classroom, and laboratory use. Lower floors remain closed until clean-up and 

repairs are completed—some lower floors will not be reoccupied until fall 2009. 

Had there been no flood damage, the wind-related damage would still have had some impact 

on facility functions. At one building, an emergency generator was damaged by water leakage 

when the roof membrane blew off. 

Figure 4-28. 

The roofs shown by 

the blue arrows were 

aggregate-surfaced BURs 

at the time Ike struck; 

the roof shown by the 

red arrow is a new roof 

replacing one that blew off
4-26 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

4 PERFORMANCE OF CRITICAL FACILITIES

Figure 4-29. 

A guyed stack that blew 

over 

Figure 4-30. 

A relief air hood blew 

off the curb allowing 

rainwater to enter the 

building
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 4-27

PERFORMANCE OF CRITICAL FACILITIES 4

Vulnerabilities and Other Observations. With the majority of UTMB buildings vulnerable to flooding at levels below the base flood, consideration should be given to moving critical functions 

and equipment to the second floor or above, or floodproofing those spaces where functions 

and equipment cannot be elevated. Use of flood-damage-resistant materials for repairs below 

the second floors of buildings would reduce future flood damages. 

Hurricane Ike’s maximum wind speed of 108 mph at this site was well below the current design 

wind speed of 132 mph. Had Ike’s winds been in the vicinity of current design conditions, the 

wind-induced damages at this facility would likely have been significantly greater. 

Considering the age of the facility and the damage experienced during Hurricane Ike and previous hurricanes, a comprehensive flood and wind vulnerability assessment should be conducted 

by a qualified team of professionals. Upon completion of the assessment, the vulnerabilities 

should be prioritized and a plan developed and implemented to mitigate the vulnerabilities in 

order to minimize future disruptions of healthcare delivery and expenditures for repairs. 

4.2.4 South Cameron Parish Hospital (Cameron, LA)

The South Cameron Parish Hospital is located on West Creole Highway and is approximately 

2.8 miles from the Gulf of Mexico shoreline. Hurricane Rita (September 2005) destroyed the 

original hospital on the site, and a new hospital facility was built on the same site. The new facility opened in November 2007, 10 months before Hurricane Ike struck.

When Hurricane Rita struck, the Effective FIRM for the area (1992) showed the hospital site as 

located in flood Zone AE, with a BFE of 9 feet NGVD. In November 2005 FEMA issued flood 

recovery guidance for Cameron Parish, which recommended 1 foot of freeboard above the Effective BFE. In March 2006, FEMA published ABFE Maps showing the site as Zone AE, with an 

Figure 4-31. 

Nine broken windows are 

shown in the red oval; the 

brown openings above the 

oval are louvers
4-28 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

4 PERFORMANCE OF CRITICAL FACILITIES

ABFE of 10 feet NGVD. The new facility was constructed with the top of the lowest floor elevation at 10 feet NGVD (Figure 4-32). Reports indicate that Hurricane Ike storm surge was just a 

few inches below that elevation at the site (Figure 4-33). The March 2008 Preliminary DFIRM, 

released by FEMA after completion of the post-Katrina and Rita flood hazard studies, shows the 

site will be remapped as Zone VE (Coastal High Hazard Areas) with a BFE of 15 feet. If rebuilt 

using the DFIRM and in accordance with ASCE 24-05, the top of the first floor of the facility 

would be at or above 17 feet NGVD. It should be noted that the flood hazard zone and BFE at 

the site were Zone V and 13 feet NGVD between 1984 and 1991, close to the 2008 preliminary 

DFIRM zone and BFE. 

The facility also received wind damage during Hurricane Ike. According to ASCE 7-05, the basic wind speed for this location is approximately 120 mph. The estimated maximum wind speed 

during Hurricane Ike was approximately 70 mph. 

General Flood Damage. The hospital property was flooded during Ike—surge did not enter the 

building but did damage conduits and piping suspended below the floor. The hospital was not 

fully functional until repairs were made and additional emergency power generation capacity 

was obtained.

The reconstructed hospital did not comply with the ASCE 24-05 elevation requirements (see Table 

4-2). While the floor height satisfied the requirements in effect at the time of construction, the utilities did not—either the utilities should have been located above the lowest floor level or the entire 

facility should have been elevated higher to allow the suspended pipes and conduits to meet the 

ASCE 24-05 utility elevation requirement. The latter approach is clearly preferable since it would 

raise the floor level another 3 feet and provide an added factor of safety against flooding. 

Figure 4-32. 

Hurricane Ike crested approximately 6 inches below the floor of the South Cameron Parish Hospital. BFEs and 

flood hazard zones are shown for the site for the period 1984 to 2008 (Note: the building code may require 

freeboard above the BFEs shown).

15.0 feet NGVD = Preliminary 

BFE, Zone V (March 2008)

10.0 feet NGVD = ABFE, 

Zone A (2006) and Top of 

Floor Elevation

9.0 feet NGVD = BFE, 

Zone A (1992)

13.0 feet NGVD = BFE, 

Zone V (1984)
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 4-29

PERFORMANCE OF CRITICAL FACILITIES 4

General Wind Damage. The main building roof system performed well during the event. However, 

some damage was sustained by the canopy over the hospital’s emergency room entrance driveway (Figure 4-34). The MAT also observed that some rooftop mechanical equipment was not 

properly fastened (Figure 4-35). 

Figure 4-33. 

Conduits and pipes 

beneath South Cameron 

Parish Hospital. Vegetation 

was noted between the 

floor system and the steel 

plate of the foundation. A 

connection between the 

plate and the floor system 

was not visible.

Figure 4-34. 

Damage to canopy over 

emergency room entrance 

driveway
4-30 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

4 PERFORMANCE OF CRITICAL FACILITIES

Functional Loss. The new hospital building was not flooded by Ike, and its emergency power generator was reportedly running when staff returned to the hospital several days after the storm. 

However, the building was not fully functional until repairs were made to conduits and piping 

suspended below the floor and until additional power generation capacity was brought in. The 

hospital’s emergency generator was reported to be an in-kind replacement for the unit lost 

during Rita and was not sufficient to fully power the new facility. Following repairs after Ike, 

the Cameron Parish government temporarily relocated several of their departments into this 

facility.

Appropriate Mitigation in New Hospital Construction. A hospital previously located at this site was 

destroyed by Hurricane Rita in 2005 and replaced with the current facility. The original South 

Cameron Memorial Hospital was constructed using Federal funds obtained from the Hill-Burton Act, and opened in 1963, 6 years after Hurricane Audrey (1957).

The original hospital facility had a floor elevation of approximately 8 feet NGVD, and the current replacement facility has a floor elevation of 10 feet NGVD (i.e., at the ABFE established 

following Rita). The estimated Rita storm surge elevation at the site was 12 to 13 feet NGVD. 

This hospital site was also subjected to significant flooding during Hurricane Audrey (1957), 

whose storm surge exceeded both the original hospital floor elevation and the new hospital 

floor elevation. 

It is not clear what, if any, influence the flood history at this site had in decisions about either 

choosing a site or floor elevation for the new facility. While it is true that Ike’s floodwaters did 

not rise above the floor of the current facility, utilities below the floor were damaged by flooding and contributed to a loss of function after Ike. 

Figure 4-35. 

Lack of proper fastening 

of rooftop equipment—a 

MAT member was able to 

easily lift this condenser 

unit off the curb. All 

equipment should be 

fastened to resist uplift 

and blow-off. 
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 4-31

PERFORMANCE OF CRITICAL FACILITIES 4

The decision to rebuild a hospital at this site with the top of its floor at the ABFE of 10 feet NGVD 

should be re-examined. While ABFEs may represent the latest available flood level information 

during a reconstruction period, critical facilities should be elevated above ABFEs—especially 

when flood levels during a recent event have reached above the ABFE or when historical BFEs 

have been mapped above the ABFE, as was the case at this site. 

The MAT also observed wind damage to the new facility. Specific attention to details that result 

in better performance in high winds should also be included in design and construction of hospitals using guidance available in FEMA 577. 

Funding decisions (by communities and State, Federal, and private entities) for reconstruction 

of critical facilities should reward adoption of best practices by the community/owner, and discourage reconstruction to minimum wind and flood requirements.

4.2.5 Hackberry Rural Medical Clinic (Hackberry, LA)

The Hackberry Rural Medical Clinic at Hackberry, LA, is located approximately 15 miles north 

of the Gulf of Mexico shoreline (Figure 4-36). The medical facility received significant flooding 

damage from Hurricane Ike. This facility was also flooded during Hurricane Rita and the damages had been repaired.

General Flood Damage. During Hurricane Ike, the facility was inundated with 3 to 4 feet of floodwater. Interior walls were damaged, as well as contents. Water-damaged gypsum board had been 

removed to a height of 5 feet above the floor (Figure 4-37) and was being replaced at the time 

of the MAT visit. 

Figure 4-36. 

Hackberry Rural Medical 

Clinic 
4-32 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

4 PERFORMANCE OF CRITICAL FACILITIES

Functional Loss. Repairs were still underway at the Hackberry Medical Clinic and the facility remained closed at the time of the MAT visit, one month after Ike. 

4.2.6 Oceanview Transitional Care Center (Texas City, TX)

The Oceanview Transitional Care Center, located in Texas City, TX, was originally built in the 

1940s as a hospital. The building received wind damage during Hurricane Ike. According to 

ASCE 7-05, the basic wind speed for this location is approximately 125 mph. The estimated 

maximum wind speed during Hurricane Ike was approximately 105 mph.

Figure 4-38 is a general view of the building. The facility houses approximately 100 residents. 

The facility was evacuated prior to the storm because of a mandatory evacuation order for Texas 

City. However, the facility that they evacuated to in Houston eventually lost all power, including 

the emergency generator. The residents therefore returned home 3 days after the storm. The facility was powered by its emergency generator for 3 days after the residents returned until power 

was restored. Although the Oceanview generator did not have sufficient capacity to power the 

HVAC system, the residents had lights, fans, and water.

General Wind Damage. The canopy roofs and a portion of the upper roof had a low parapet. The 

remainder of the upper roof had metal edge flashing. The coping blew off a portion of one of 

the canopies and a portion of the main roof. Exposed fasteners were used to attach the inner 

leg of the copings. In one area, the fasteners were 3 feet 2 inches on center, which is very excessive spacing. Had the winds been stronger, roof blow-off associated with coping failure would 

have been likely.

Figure 4-37. 

Hackberry Rural Medical 

Clinic interior repairs in 

progress 
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 4-33

PERFORMANCE OF CRITICAL FACILITIES 4

An exhaust fan on the upper roof blew off, because of an inadequate number of fasteners, and 

landed on a canopy roof (Figure 4-39). A temporary covering had been placed over the curb, 

but at the time of MAT observations, the covering was no longer in place. Two other fans also 

lost their cowlings, and a fan on a lower level roof blew off. There was minor water leakage to 

the interior of the facility (in part or solely related to this rooftop equipment damage).

The LPS became detached from several areas of the main roof. Portions of the conductors were 

dangling over the front and back walls (Figure 4-40). In addition to loss of lightning protection, 

the detached conductors had the potential to break glazing.

Functional Loss. There was no loss of function to this building as a result of Hurricane Ike. 

Vulnerabilities and Other Observations. Had the winds been stronger, significant water infiltration 

would have been likely due to roof membrane blow-off associated with edge flashing or coping 

failure. Additionally, since the roofs were aggregate-surfaced BURs, aggregate blow-off would 

have been likely, which depending upon wind direction, may have resulted in damage to the facility’s windows and/or glazing damage to automobiles or nearby buildings. 

Figure 4-38. 

General view of 

Oceanview Transitional 

Care Center
4-34 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

4 PERFORMANCE OF CRITICAL FACILITIES

Figure 4-39. 

The fan shown in the inset 

blew off of this curb
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 4-35

PERFORMANCE OF CRITICAL FACILITIES 4

4.3 First Responder Facilities (Police/Fire/EOC)

First responder facilities, including fire stations, police, and EOCs, are considered lifelines in 

communities. Their employees perform a community’s first response function and play a critical role in ensuring the safety of all residents and protection of residences and infrastructure. 

For this reason, the performance of these facilities in hurricanes is of utmost importance.

4.3.1 Houston Transtar – Regional EOC (Houston, TX) 

The Houston TranStar – Regional EOC is housed in a building constructed in 1996 (Figure 

4-41). The Houston TranStar consortium is a partnership of four government agencies responsible for providing transportation management to the greater Houston area. In addition, it 

serves as a regional EOC to 14 counties. The Regional EOC building received some wind damage from Hurricane Ike. According to ASCE 7-05, the basic wind speed for this location is 

approximately 108 mph. The estimated maximum wind speed during Hurricane Ike was approximately 92 mph.

Figure 4-40. 

Detached LPS conductor
4-36 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

4 PERFORMANCE OF CRITICAL FACILITIES

The roof deck for the facility is a composite concrete topping over steel decking, and the roof 

covering is a mineral surface modified bitumen membrane. Both the decking and the roof covering types are recommended in FEMA 543. The building originally had shutters to protect the 

windows. However, because of the time and expense involved with installing and removing the 

shutters, the windows were replaced with impact-resistant windows in 2004.

Figure 4-41. 

Houston Transtar Regional 

EOC; significant permanent 

outward deformation 

occurred at the gutter 

shown in the inset
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 4-37

PERFORMANCE OF CRITICAL FACILITIES 4

General Wind Damage. Hurricane Ike caused outward deformation of the gutter shown in the 

Figure 4-41 inset. Had the winds been stronger, the gutter would have likely blown off. Additionally, several pieces of coping blew off the building. The outer face of the coping is 8 inches and 

the inner face is 4 inches (Figure 4-42). Continuous cleats are located along both sides of the 

parapet. The cleats were attached with roofing nails driven through the horizontal flange (blue 

arrow at Figure 4-42). In addition, a few widely-spaced nails were driven through the vertical 

flange (red arrow in Figure 4-42). The nailing provided very little resistance to outward deflection of the cleat and coping. While most of the continuous inner and outer cleats remained 

on the building, several sections of coping and at least one cleat blew off once the amount of 

deflection was sufficient for the coping to disengage from the cleat. The blown-off cleat had a 

face nail that was 75 inches in from the end of the cleat, hence over 6 feet of this cleat was unrestrained from outward deformation. 

The wind resistance of poorly attached copings, such as the ones on this building, can be economically strengthened by face-screwing the coping as described in FEMA 543. The base flashing 

was stopped at the top of the parapet. It should have been run across the top of the nailer and 

turned down and nailed so as to provide greater watertight protection in the event of coping 

leakage or coping blow-off.

Figures 4-43 and 4-44 show pieces of coping that landed elsewhere on the roof. Windborne 

coping can easily puncture roof membranes, including tough membranes like the modified bitumen membrane on this roof (inset at Figure 4-43).

Figure 4-42. 

The coping blew off 

because of inadequate 

attachment of the cleats. 

The blue arrow shows 

roofing nails driven 

through the horizontal 

flange and the red arrow 

shows widely spaced nails 

through the vertical flange. 
4-38 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

4 PERFORMANCE OF CRITICAL FACILITIES

A substantial amount of leaf debris was observed in the vicinity of scuppers on a lower roof (Figure 4-44). During hurricanes, heavy leaf loss and accumulation on roofs has the potential to 

block roof drains and overflow drains and scuppers. Increasing the size of scuppers and downspouts minimizes the potential for scupper/downspout blockage.

Figure 4-43. 

Coping debris (red arrow); 

the membrane was 

gouged (blue arrow) by 

coping debris (an ink pen 

shows the scale) 

Figure 4-44. 

Coping debris (blue arrow) 

on a lower roof; note leaf 

debris near the scupper 

(red arrow)
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 4-39

PERFORMANCE OF CRITICAL FACILITIES 4

Additional damage included minor leakage at a building expansion joint and toppling of a tall 

flue on a lower level roof, even though it was guyed (Figure 4-45). The tautness of guys should 

be checked annually to avoid toppling of flues.

Figure 4-45. 

Guyed flue blew over (red 

arrow indicates one of the 

guys)

Functional Loss. The building did not experience loss of function as a result of Hurricane Ike. 

However, the building experienced a power interruption when the Red Cross was allowed to 

connect to the building’s electrical system (which at that time was being powered by the building’s emergency generator). The power interruption resulted in a complete loss of electrical 

power to the building for approximately 15 minutes. 

The building did not experience loss of water or sewer service.

Vulnerabilities and Other Observations. Had the winds been stronger, significant water infiltration 

would have been likely due to roof membrane blow-off associated with the coping failure. The 

gutters would likely have also blown off, which may have caused blow-off of the metal roof panels. Additional damage to rooftop equipment would also have occurred.

Under the right wind conditions, the emergency generator could also have been damaged because of inadequate building envelope protection. The facility’s one emergency generator is 

housed in a separate building, shown in Figure 4-46. The coiling doors shown by the red arrow 

in Figure 4-46 appeared to possess little wind resistance. In addition, the louver shown by the 

blue arrow was not resistant to large windborne debris (which could penetrate the louver and 

damage the generator). Considering the importance of this facility, it would be prudent to: 1) 

add a back-up generator and a cam locking box (to facilitate rapid connection of a portable 

generator); 2) replace the coiling door with a new door rated for the design wind load and 
4-40 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

4 PERFORMANCE OF CRITICAL FACILITIES

capable of resisting test missile E as specified in ASTME E 1996; and 3) replace the louver with 

one capable of resisting test missile E, or provide a debris-resistant shield in front of the louver. 

Recommendations pertaining to all three of these items are provided in FEMA 543.

Figure 4-46. 

The emergency generator 

is housed in the circled 

building; the coiling door 

(red arrow) and the louver 

(blue arrow) appeared 

to provide inadequate 

protection for the 

generator

The facility had a very large water tank to provide potable water and water for the building’s fire 

sprinkler system, which provides protection in the event of an interruption of municipal water. 

4.3.2 Deer Park Police Station (Deer Park, TX)

The Deer Park Police Station (Figure 4-47), constructed in 2004, received wind-driven rain 

damage as a result of Hurricane Ike. According to ASCE 7-05, the basic wind speed for this 

location is approximately 112 mph. The estimated maximum wind speed during Hurricane 

Ike was approximately 95 mph. Shutter mitigation work was conducted after the building was 

constructed. 

General Wind Damage. There was no apparent wind damage. However, relatively minor water leakage occurred. The building owner reported that wind-driven rain entered at the metal roof’s 

ridge flashing.

Functional Loss. There was no loss of function at this facility from Hurricane Ike. It cost approximately $3,000 to repair the interior damage caused by the leakage. 

Vulnerabilities and Other Observations. When the facility undertook shutter mitigation work, 

conducting a comprehensive vulnerability assessment and then mitigating the significant vulnerabilities, or alternatively, recognizing the residual risk that remains, would have been prudent 

(see FEMA 543). The MAT observed the following vulnerabilities.
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 4-41

PERFORMANCE OF CRITICAL FACILITIES 4

The gutter brackets shown in Figure 4-48 do not provide a positive attachment between the 

gutter and bracket. However, the winds during Hurricane Ike were not of sufficient strength to 

blow off the gutters. Screwing the gutter to the brackets, as shown in the inset at Figure 4-48 (the 

inset photo is from an HMPG project in Port Neches), would be prudent. However, to avoid 

leakage at the fasteners between the bracket and gutter, the bracket should extend near or to 

the top of the gutter so that the fastener would be above the waterline. 

Figure 4-47. 

General view of Deer Park 

Police Station

Figure 4-48. 

The gutters are not 

attached to the gutter 

bracket; the inset shows 

a bracket at another 

building that provides 

a positive connection 

between the bracket and 

gutter
4-42 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

4 PERFORMANCE OF CRITICAL FACILITIES

The emergency generator is shown in Figure 4-49. Although the enclosure has walls around 

three sides, it does not provide sufficient wind and windborne debris protection. Had the generator failed to function during the storm, lack of protection would have inhibited maintenance 

efforts to get the generator back online. FEMA 543 recommends providing a wind- and windborne-debris-resistant enclosure all around and over the generator.

The facility’s emergency generator provided power during intermittent municipal power outages. There was no interruption of water or sewer service.

Figure 4-49. 

The emergency generator 

is inadequately protected 

from wind and windborne 

debris

4.3.3 Port Neches Fire Station (Port Neches, TX)

The Port Neches Fire Station (Figure 4-50) was constructed in 1972. In the aftermath of Hurricane Rita (2005) and at the time that Hurricane Ike struck, this building was being mitigated 

using HMGP funds. The mitigation work consisted of replacing all six apparatus bay sectional 

doors, adding window and door shutters (Figure 4-51), and installing a new modified bitumen 

roof system. At the time of Hurricane Ike, all the work had been completed except installation 

of some of the metal edge flashing. According to ASCE 7-05, the basic wind speed for this location is approximately 116 mph. The estimated maximum wind speed during Hurricane Ike was 

approximately 90 mph.

General Damage. This facility was not damaged during Hurricane Ike. 

Functional Loss. There was no functional loss to this facility during Hurricane Ike. 
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 4-43

PERFORMANCE OF CRITICAL FACILITIES 4

Vulnerabilities and Other Observations. The MAT observed vulnerabilities that make the building 

susceptible to: 1) leakage due to roof membrane puncture from windborne debris, 2) fan and/

or fan cowling blow-off, and 3) emergency generator damage from windborne debris. 

Performance of HMGP Mitigation Work. When the facility undertook mitigation work, it would 

have been prudent to conduct a comprehensive vulnerability assessment and then mitigate 

the significant vulnerabilities, or alternatively, recognize the residual risk (see FEMA 543).

Figure 4-50. 

General view of Port 

Neches Fire Station 

Figure 4-51. 

View of a new motorized 

shutter; the toggle in 

the red circle allows the 

shutter to be manually 

raised
4-44 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

4 PERFORMANCE OF CRITICAL FACILITIES

Replacing the sectional doors, adding the shutters, and replacing the roof system were appropriate actions for the mitigation project. However, the new roof system does not provide leakage 

protection in the event the membrane is punctured by windborne debris. Although the roof 

membrane choice was appropriate (and one that is recommended in FEMA 543), the new roofs 

do not have secondary membranes, as recommended in FEMA 543, to avoid water leakage in 

the event the membranes are punctured by windborne debris. 

Neither the exhaust fan cowlings nor the fans were anchored as recommended in FEMA 543. 

The contract documents specified two screws per side, with a maximum spacing of 16 inches on 

center; however, for this size fan, FEMA 543 recommends four screws per side. 

The emergency generator is not located in a protected enclosure (Figure 4-52). The nearby 

non-reinforced masonry screen wall (red arrow) could collapse on the generator, and the generator could be damaged by windborne debris. Had the generator failed to function during the 

storm, lack of protection would have inhibited maintenance efforts to get the generator back 

online. As part of a comprehensive mitigation project, providing a wind- and windborne-debrisresistant enclosure all around and over the generator as recommended in FEMA 543 would 

have been prudent.

Figure 4-52. 

The emergency 

generator is susceptible 

to windborne debris 

and damage caused by 

collapse of the masonry 

screen wall
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 4-45

PERFORMANCE OF CRITICAL FACILITIES 4

4.3.4 High Island Fire Station (High Island, TX)

The High Island Fire Station is an older pre-engineered metal building (Figure 4-53). The facility received wind damage during Ike. According to ASCE 7-05, the basic wind speed for this 

location is approximately 131 mph. The estimated maximum wind speed during Hurricane Ike 

was approximately 110 mph.

General Wind Damage. All four apparatus bay doors blew away when the door rollers disengaged 

from the tracks (Figure 4-53). 

At the back of the building, the bottom of the wall blew outward (Figure 4-54). The metal walls 

were attached to an angle that was poorly attached to the concrete slab. The angle was attached 

at the door jamb, but there was a 10-foot gap to the next adjacent fastener. Some wall insulation 

near the door was also blown away. In addition, some of the metal wall panels peeled back at a 

corner of the building.

Functional Loss. There was no functional loss to this facility during Hurricane Ike.

Vulnerabilities and Other Observations. The apparatus (trucks) appeared to be left in the fire station during the storm. Older buildings such as this are quite susceptible to damage (including 

collapse of the structural frame if winds are quite high). When apparatus are left in a station 

such as this, they can be damaged by building collapse. 

Figure 4-53. 

General view of High 

Island Fire Station
4-46 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

4 PERFORMANCE OF CRITICAL FACILITIES

4.3.5 Louisiana Fire Stations 

If fire stations cannot remain operational during or after an event, the community loses a valuable and important part of its emergency response capability. The MAT visited and inspected 

five fire stations in Louisiana:

n Grand Caillou Volunteer Fire Station, Terrebonne Parish

n Bayou Dularge Volunteer Fire Station, Terrebonne Parish

n 7th Ward Volunteer Fire Department, Vermilion Parish

n Hackberry Volunteer Fire Station, Cameron Parish

n Grand Isle Volunteer Fire Station, Jefferson Parish

The MAT also saw, but did not inspect, flood damage to metal building systems and fire equipment at other fire stations (e.g., Muria Road Fire Station and East Creole Highway Station, 

Cameron Parish). A summary of the observations for each facility is included in Table 4-3.

Figure 4-54. 

The metal wall at the red 

oval area was pushed 

outward because of 

inadequate attachment of 

the wall angle to the slab
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 4-47

PERFORMANCE OF CRITICAL FACILITIES 4

Table 4-3. Observations of Louisiana Fire Stations

Fire Station Parish Ike Damage Comments

Grand Caillou 

Volunteer Terrebonne None Elevated above ABFE (Figure 4-55); manned during 

Hurricane Ike, no loss of function

Bayou 

Dularge 

Volunteer

Terrebonne Foundation 

undermined

Sited along the bank of a canal, rear of building was 

undermined by bank erosion during Ike (Figure 4-56); 

erosion also occurred during Rita and had been repaired 

before Ike; manned during Ike, no loss of function; bank 

stabilization required. The Parish Council agreed to 

condemn the station in February 2009, and its operations 

will move to another station.

7th Ward 

Volunteer Vermilion Flood

Approximately 8 inches of flooding above the floor during 

Ike; repairs underway during MAT visit (Figures 4-57 and 

inset); previously flooded during Rita; station was not in 

use during Ike.

Hackberry 

Volunteer Cameron Flood

Flooded during Ike; previously flooded during Rita, after 

which the station had been cleaned but not fully repaired; 

station was not in use during Ike, although vehicles and 

equipment were damaged by flooding; replacement HVAC 

units from Rita were not elevated (Figure 4-58).

Grand Isle Jefferson Flood

Facility sustained wind and flood damage during Katrina 

that had not been repaired at the time of Ike (Figure 4-59); 

facility sustained additional flood damage during Ike, but 

was not in operation at the time and is now used only as a 

garage.

Muria Road Cameron Flood Obvious flood damage to the metal building was evident 

during a drive-by. 

East Creole 

Highway Cameron Flood Obvious flood damage to the metal building was evident 

during a drive-by.

Figure 4-55. 

The Bayou Grand Caillou 

Fire Station is elevated 

above the ABFE and 

sustained no damage
4-48 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

4 PERFORMANCE OF CRITICAL FACILITIES

Figure 4-56. 

Rear of Dularge Fire 

Station; note canal bank 

erosion sustained during 

Hurricane Ike 

Figure 4-57. 

7th Ward Fire District No.1 

Fire Station; wall repairs 

were in progress during 

MAT inspection
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 4-49

PERFORMANCE OF CRITICAL FACILITIES 4

Figure 4-58. 

Condenser units were 

installed at Hackberry 

Fire Station after Ike and 

are vulnerable to future 

flooding

Figure 4-59. 

Wind damage (red arrows) 

to Grand Isle Fire Station 

remaining from Hurricane 

Katrina
4-50 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

4 PERFORMANCE OF CRITICAL FACILITIES

 4.4 Other Government Buildings

Although few government buildings are categorized as critical facilities in ASCE 7-05 (i.e., Category III or IV buildings), many government buildings play a vital role in delivering various 

services during and/or after a hurricane and should receive additional design attention to avoid 

or resist flood and wind loads. 

4.4.1 U.S. Army Corps of Engineers Administration Building (Galveston, TX)

The USACE Administration Building (Figure 4-60), constructed in 1991, is located in Galveston, 

TX. Although the building was not damaged by flooding, floodwater surrounded the building 

during Hurricane Ike. Had the water been a few inches higher, it would have wetted the first 

(lobby) floor. The building experienced wind damage from Hurricane Ike. The exterior walls 

are precast concrete. According to ASCE 7-05, the basic wind speed for this location is approximately 132 mph. The estimated maximum wind speed during Hurricane Ike was approximately 

108 mph.

Figure 4-60. 

General view of the USACE 

Administration Building in 

Galveston, TX

General Wind Damage. Some minor leakage occurred at a few windows; facility staff reported that 

minor leakage had also occurred during previous thunderstorms. Additionally, some fan cowlings and louvers at condensers were blown off, and some of the LPS conductors detached from 

the roof membrane. A sheet metal cover over a curb was blown off (Figure 4-61). The presence 

of the 3-foot 2-inch high parapet was the likely reason the sheet metal was not blown from the 

roof. The roof membrane is a mineral-surface modified bitumen membrane (which is relatively 

tough and one of the membrane types recommended in FEMA 543). Although the sheet metal 

scuffed the roof, the membrane was not punctured or torn. 
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 4-51

PERFORMANCE OF CRITICAL FACILITIES 4

Functional Loss. The emergency generator for the facility is fueled by natural gas. The gas supply was shut down prior to the storm by the gas supplier. The facility was without power until a 

portable generator was supplied by FEMA on September 21. Municipal power was restored on 

September 30. Additionally, the building was without potable water until October 2. The building was reoccupied on October 6.

Vulnerabilities and Other Observations. The incorporation of many sound design elements (e.g., 

precast concrete walls, a modified bitumen membrane, and a parapet in excess of 3 feet) makes 

this a relatively wind-resistant building. However, strengthening the attachment of the rooftop 

equipment and the LPS, constructing a wind- and debris-resistant enclosure around the exposed emergency generator, and providing a contingency for future natural gas interruption 

(see Chapter 7, Recommendations) would be prudent. 

4.4.2 Federal Courthouse and Post Office (Galveston, TX)

The Federal Courthouse and Post Office (U.S. Postal Service) facility (Figure 4-62), constructed 

circa 1935, is located in Galveston, TX. The facility received some flood damage. The facility 

also had minor wind damage. According to ASCE 7-05, the basic wind speed for this location 

is approximately 132 mph. The estimated maximum wind speed during Hurricane Ike was 

Figure 4-61. 

The black material on top of the curb is a temporary covering to 

replace the sheet metal covering originally on the curb; shown in 

the red circle and inset
4-52 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

4 PERFORMANCE OF CRITICAL FACILITIES

approximately 107 mph. The upper level roof is composed of two types. The steep-slope portion is tile. All of the tails of the tiles are hooked (red circle in Figure 4-63). The sloped roofs 

surround a low-slope area that has a mineral-surface modified bitumen membrane. 

Figure 4-62. General view 

of Federal Courthouse and 

Post Office; some flashing 

damage occurred during 

Hurricane Ike (shown by 

red arrow)

Figure 4-63. 

All of the tile tails were 

hooked

This building is on the site of the former Federal Courthouse and Post Office designed by Nicholas 

Clayton, a prominent Galveston architect (the first professional architect in the State), and was built between 1888 and 1892. In 1993, during construction of 4- to 5-foot deep foundation trenches for the new 

generator building, the upper portions of a 3- to 5-foot foundation and the remains of a marble floor were 

exposed. The exposed foundation and marble floor were determined to be the northwest corner of the 

former courthouse/post office/customs building. 
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 4-53

PERFORMANCE OF CRITICAL FACILITIES 4

General Flood Damage. Floodwater inundated the basement, which caused major damage to mechanical equipment and the main electrical switchgear room.

General Wind Damage. In one of the offices, there was damage to ceilings and interior partitions. 

The MAT assumption is that the damage was caused by wind entering the office through a window that became unlatched and opened during the storm.

No roof covering damage was observed. Some roof flashing damage occurred along a small area 

on the front of the building (red arrow, Figure 4-64) and similarly along the back of the building. Minor rooftop equipment damage was observed. An access panel at a condenser was nearly 

blown off (red arrow, Figure 4-64). The condenser had two supplementary anchor straps (yellow arrows). Supplementary anchor straps are recommended in FEMA 543.

Figure 4-64. 

The access panel (red 

arrow) nearly blew away; 

the yellow arrows indicate 

supplementary anchor 

straps

Functional Loss. At the time of the MAT visit, the facility was closed due to flood damage to the 

mechanical equipment and switchgear in the basement.

Vulnerabilities and Other Observations. A good practice observed at this facility is the location of the 

emergency generator in a wind- and windborne-debris-resistant building and elevation above 

the floodwater level (Figure 4-65). Hence, although flooding damaged the switchgear in the 

basement, the emergency generator was functional and, therefore, able to be reconfigured to 

power portable equipment used to dry the interior of the building.
4-54 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

4 PERFORMANCE OF CRITICAL FACILITIES

Figure 4-66. 

One of the shutters at 

the Tiki Island City Hall 

is shown in the red oval; 

blue arrows indicate 

breakaway walls that 

performed successfully by 

breaking away

4.4.3 Tiki Island City Hall (Tiki Island, TX)

The Tiki Island City Hall (Figure 4-66), constructed around 1986, is located on Tiki Island, a 

barrier island between the mainland and Galveston Island. In the aftermath of Hurricane Rita, 

the building was mitigated in 2008 using HMGP funds. The mitigation work consisted of adding 

motorized shutters at all glazed openings. The facility received wind and flood damage during 

Hurricane Ike. According to ASCE 7-05, the basic wind speed for this location is approximately 

130 mph. The estimated maximum wind speed during Hurricane Ike was approximately 103 

mph.

Figure 4-65. 

The emergency generator 

is housed in a separate 

wind- and windbornedebris-resistant building 

(red arrow)
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 4-55

PERFORMANCE OF CRITICAL FACILITIES 4

General Flood Damage. Breakaway walls failed under flood forces and ground level space was inundated (blue arrows in Figures 4-66 and 4-68).

General Wind Damage. A portion of the ridge flashing was blown off the metal roof (Figure 4-67). 

Leakage did not occur, so the roof underlayment was apparently correctly lapped over the ridge. 

However, loss of flashing can make roof panels more susceptible to blow-off.

Figure 4-67. 

The oval shows where 

ridge flashing blew away

Functional Loss. There was no loss of function at this facility. A few of the breakaway walls broke 

away as intended, but that damage did not significantly affect facility operations.

An exposed emergency generator that powers the City’s sewage treatment facility failed due to 

corrosion in the electronic controls. This was an older generator that was scheduled for replacement in a year or two, so less attention had been given to maintenance. Municipal power was 

restored within 5 or 6 days, which allowed the sewage treatment facility to come back online. 

This generator also supplied power to the City Hall.
4-56 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

4 PERFORMANCE OF CRITICAL FACILITIES

Vulnerabilities and Other Observations. The building design incorporated a very sound practice regarding entrance of electrical service. Normally when power is provided by overhead lines (as is 

the case with this building), the lines come into a weatherhead that penetrates the roof. If nearby power poles collapse or move significantly, the power lines pull the weatherhead, which often 

tears the roof and allows leakage. However, at this building, the conduit from the weatherhead 

(circled in Figure 4-68) runs along the wall and then enters the building through the wall (red 

arrow). With this installation, movement of the power lines may have caused some damage at 

the wall penetration had the power lines moved significantly; but if wall damage had occurred, 

leakage would have been much less problematic than if the conduit penetrated the roof.

Performance of HMGP Mitigation Work. When the facility undertook mitigation work, it would have 

been prudent to conduct a comprehensive vulnerability assessment and then mitigate the significant vulnerabilities, or alternatively, recognize the residual remaining risk (see FEMA 543). 

The addition of shutters via the HMGP mitigation project was prudent; however, other building 

vulnerabilities (i.e., the roof ridge flashing and emergency power) were not addressed. 

Figure 4-68. 

The electrical service 

entered through the wall 

rather than the roof; the 

blue arrows indicate 

missing breakaway walls

4.4.4 Terrebonne Parish Criminal Justice Complex (Houma, LA)

The Terrebonne Parish Criminal Justice Complex located in Houma, LA, houses approximately 

600 inmates. It is a relatively new facility but received approximately 18 to 24 inches of flooding 

due to Hurricane Ike (Figure 4-69). 

The facility was also flooded during Hurricane Rita in 2005. The 1985 FIRM showed the site as 

being in flood Zone C (outside the limits of the 500-year flood), but the February 2006 (post-Rita) flood recovery map shows the area as advisory flood Zone A with an advisory flood elevation 

of 6 feet NGVD, approximately comparable to the elevation of Hurricane Rita flooding.
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 4-57

PERFORMANCE OF CRITICAL FACILITIES 4

General Flood Damage. Utility service, which runs beneath the slab foundation, was damaged and 

disrupted by Ike’s flooding. In addition to the inundation problems, the facility became unusable 

because controls were either damaged or inoperable (virtually all of the functions of the prison 

are operated by electric switches, relays, and motors, including the communications, prison monitors, lights, and cell doors). Parish records also indicate that the criminal complex electronic 

security system was damaged by Hurricane Rita and required repair and replacement in 2006.

Functional Loss. Flooding damaged essential equipment and required that prisoners be relocated to a State corrections facility. 

Vulnerabilities and Other Observations. ASCE 7-05 and ASCE 24-05 designate jails and detention facilities as Category III facilities, which require additional design consideration beyond building 

code requirements for typical commercial and residential construction. Correctional facilities 

should be located outside the floodplain or elevated to the 500-year flood elevation. If 500-year 

flood elevations are not available, elevate above the BFE with sufficient freeboard to prevent 

damage and loss of use. Some States have mandated special permit requirements and freeboard 

for correctional facilities located in or near flood hazard areas (e.g., Commonwealth of Pennsylvania, 2001). Federal agencies with involvement in funding, permitting, and constructing 

critical facilities should follow these guidelines for protecting correctional facilities in accordance with Executive Order 11988 Floodplain Management.

The U.S. Department of Justice (DOJ), National Institute of Corrections provides specific guidance for planning for emergencies, including natural disasters. All correctional facilities in 

hazardous areas can conduct a self-audit using the convenient checklists in the DOJ publication (Schwartz and Barry, 1996), and should identify retrofit opportunities and procedures to 

reduce damage and overcome operational issues related to natural disasters. 

Figure 4-69. 

Terrebonne Parish 

Criminal Justice Complex 

HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 5-1

PERfORMANcE Of BuIldINGS IN HOuSTON'S cENTRAl BuSINESS dISTRIcT 5

Performance of Buildings in 

Houston’s Central Business 

District 

Although Hurricane Ike’s winds were not as high as the current 

design wind speed, some buildings received extensive exterior envelope 

damage.

The MAT observed various types of building envelope damage at several buildings in downtown 

Houston. According to ASCE 7-05, the basic wind speed for downtown Houston is approximately 108 mph. The estimated maximum speed during Hurricane Ike was approximately 94 mph. 

Although Hurricane Ike’s winds were not as high as the current design wind speed, some buildings received extensive exterior envelope damage. Most of the damage was to glazing and roof 

coverings. Sections 5.1 to 5.3 describe the types of buildings and building damage observed by 

the MAT. Vegetative roofs are discussed in Section 5.4. 

5Performance of Buildings in 

Houston’s Central Business 

Tom Smith

David Conrad
5-2 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

5 Performance of Buildings in Houston's Central Business District

Good structural system performance is critical to avoid injury to occupants and minimize 

damage to a building and its contents; however, 

good structural system performance alone does 

not ensure occupant or building protection. 

Good performance of the building envelope is 

also critical. Glazing can be very expensive to replace, as is replacing a roof system. In addition, 

once a building envelope is breached, costs are 

incurred due to wind and/or water damage to 

interiors and contents (Section 5.2.1). Interruption of businesses when businesses are forced to 

vacate because of damaged buildings can result 

in even greater costs. The costs associated with 

interruption and temporary relocation often exceed the direct costs of repairing the damaged 

buildings and their contents. 

Following Hurricane Alicia in 1983, a committee of the Houston Construction Industry Council—with participation from the City’s building 

department—recommended a code change to the City of Houston Building Code that prohibited the use of aggregate on roof surfaces over 55 feet above grade (Smith, 1997). However, the 

City Council did not accept the recommendation and local code continued to allow aggregate 

surfacing on BURs. In January 2006, the City of Houston adopted the 2003 edition of the IBC 

(with local amendments). One of the local amendments (1504.8) was a response to changes 

in the 2006 edition of the IBC prohibiting aggregate (referred to as “gravel or crushed stone”) 

roof surfaces. Although the 2006 IBC prohibits all roof aggregate (regardless of size) in hurricane-prone regions, Houston’s building department does not interpret the local amendment as 

applicable to 1 1⁄2-inch or larger aggregate (which is used on aggregate ballasted single-ply roof 

membranes). As a result, after nearly 23 years, the local code prohibits installation of aggregatesurfaced BURs, but continues to allow installation of aggregate-ballasted roof systems and does 

not require abatement of existing aggregate-surfaced roofs.

The MAT observed commercial high-, mid-, and low-rise buildings in downtown Houston. The 

building ages ranged from several decades to just a few years old. Figure 5-1 shows an aerial photograph of a portion of downtown Houston. There was significant building envelope damage in 

areas indicated by the blue and red circles on Figure 5-1; the red circle denotes buildings that 

are discussed as cluster A (Section 5.2), and the blue circle denotes buildings discussed as cluster B (Section 5.3). Random isolated envelope damage was observed in the areas outside the 

clusters, as described in Section 5.1.

5.1 Areas Outside Clusters A and B

Several of the buildings outside of the clusters had limited glazing damage, ranging from one or 

a few broken windows to several broken windows as shown in Figure 5-2. At the building shown 

HURRICANE ALICIA (1983)

Downtown Houston is infamous for glazing damage during Hurricane Alicia. More 

downtown glazing was broken during that 

hurricane than during or since any other 

U.S. hurricane. Extensive glass breakage 

was documented at six high-rise buildings 

(Savage et al., 1984 and Kareem, 1986). 

The number of broken windows and glass 

spandrel panels was reported on three 

buildings as follows: 1,100 to 1,200 units, 

630 units, and 80 to 100 units. More than 

80 percent of the glazing damage in the 

central business district was attributed to 

windborne debris impact. Aggregate from 

BURs was identified as a major contributor of the debris. 
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 5-3

PERfORMANcE Of BuIldINGS IN HOuSTON'S cENTRAl BuSINESS dISTRIcT 5

CLUSTER A

CLUSTER B

Figure 5-1. 

View of a portion of downtown Houston. The red circle denotes cluster A and the blue circle denotes cluster B. 

SoURCE: NoAA, SEpTEMBER 17, 2008
5-4 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

5 PERfORMANcE Of BuIldINGS IN HOuSTON'S cENTRAl BuSINESS dISTRIcT

in Figure 5-2, 79 windows on one face were boarded up (presumably both the inner and outer 

panes were broken). For at least five other windows, the outer pane was also broken on this façade (these windows were not boarded).

Glazing breakage also occurred several floors above grade at other buildings. There was also 

random breakage at or near street level at some buildings, as shown in Figure 5-3. Exterior 

glazing is very susceptible to windborne debris breakage unless it is impact resistant (via use 

of laminated glass or shutters). Since Houston is not in a windborne debris region, protected 

glazing is not commonplace. The probability that any one window will be struck by windborne 

debris is typically small (unless the glazing is downstream from an aggregate-surfaced roof). The 

probability of impact depends upon local wind characteristics and the amount of natural and 

manmade windborne debris in the vicinity. The greater the wind speed, the greater the amount 

of windborne debris that is likely to become airborne. Glazing can also be broken by overpressurization via either high negative or positive wind loads, but this damage is not as common as 

debris-induced damage. Older glazing is more susceptible to wind-load damage because it is 

often weakened by scratches. In addition, much of the older glazing on low-rise buildings was 

installed when little attention was given to wind resistance.

Figure 5-2. 

Building with glazing damage; location shown by yellow square in inset

CLUSTER A

CLUSTER B
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 5-5

PERfORMANcE Of BuIldINGS IN HOuSTON'S cENTRAl BuSINESS dISTRIcT 5

Windborne debris in the downtown area included glass shards, rooftop mechanical equipment, 

roof aggregate, wall coverings (Figure 5-4), building signage, and tree limbs. Some of the debris 

was of relatively high momentum (Figure 5-5).

Figure 5-3. 

Random breakage of first 

floor glazing

CLUSTER A

CLUSTER B

Figure 5-4. 

Portions of the mechanical equipment screen wall blew 

away. Location shown by yellow box in bottom inset.
5-6 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

5 PERfORMANcE Of BuIldINGS IN HOuSTON'S cENTRAl BuSINESS dISTRIcT

Figure 5-5. 

The wire mesh of 

this stucco wall was 

penetrated by windborne 

debris. The impact location 

is about 5 feet above the 

sidewalk.

5.2 Cluster A – JP Morgan Chase Area

An enlarged view of cluster A is shown in Figure 5-6. The JP Morgan Chase Tower and Center 

are part of cluster A. 

n JP Morgan Chase Tower. Built in 1982 and standing 75 stories (1,000 feet), this is the tallest 

building in Houston. The building never lost power during the event, as power is fed 

from two vaults from two different substations. This building sustained significant glazing 

damage (Section 5.2.1).

n JP Morgan Chase Center. Built in 1982, this is a 20-story (240-foot) building. Floors 1 

through 13 are a parking garage. Floors 14 through 20 are offices. Virtually all of the 

glazing on one façade was damaged (Section 5.2.1) and the main roof covering was 

blown off (Section 5.2.4). 
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 5-7

PERfORMANcE Of BuIldINGS IN HOuSTON'S cENTRAl BuSINESS dISTRIcT 5

1 All estimated speeds in this Chapter are peak gust, Exposure C at 33 feet taken from Estimates of Maximum Wind Speed 

Produced by Hurricane Ike in Texas and Louisiana (ARA, 2008)

Figure 5-6. 

JP Morgan Chase Tower 

and JP Morgan Chase 

Center. The arrows show 

Hurricane Ike’s primary 

wind directions (see text 

box) and maximum gust 

speed (for Exposure C at 

33 feet above grade) for 

the given direction.1

SoURCE: NoAA, SEpTEMBER

17, 2008 

WINd dIRECTIoNS ANd SPEEdS IN doWNToWN HoUSToN

The variation in wind speeds and wind directions shown in Figures 5-6 and 5-16 were derived from 

measurements obtained from a Florida Coastal Monitoring program 10-meter tower located on the 

University of Houston Campus. The magnitudes of the wind speeds were adjusted in two ways, as 

follows: 

(1) Since the measurements were taken in an area with a terrain exposure best described as suburban, 

the wind speeds were converted to equivalent open country exposure conditions to facilitate comparison with basic design wind speeds specified in the 2006 IBC / ASCE 7-05. The terrain conversion 

resulted in an increase of 17 percent in the gust wind speeds over the actual measurements. 

(2) The tower data represent measurements at a single point. However, the wind field model developed by ARA (2008) considers data from many sources and represents a smoothed estimate of 

wind speeds throughout the area. Therefore, the open terrain wind speed estimates computed from 

the actual tower measurements were increased by an additional 7 percent to be consistent with the 

ARA wind field estimates for downtown Houston.

Texas Ave.

Capitol St.

Travis St.

Milam St.

Main St.

JP MoRGAN CHASE ToWER

JP MoRGAN CHASE CENTER
5-8 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

5 PERfORMANcE Of BuIldINGS IN HOuSTON'S cENTRAl BuSINESS dISTRIcT

5.2.1 Glazing 

JP Morgan Chase Tower

The glazing panes of the JP Morgan Chase Tower are 1⁄4-inch thick each, inner and outer, with a 

1⁄2-inch air space between the panes. The glazing units are tinted and annealed. There was significant damage on the southeast façade, which was on the leeward side of the building during the 

time of the strongest winds (yellow circled area in Figure 5-7 and yellow arrow in inset), where 

both the inner and outer panes of approximately 463 windows were broken. On that façade, all 

windows in the first 22 floors were broken. The highest broken window was on the 47th floor.

The southwest façade had 23 windows with broken inner and outer panes, and the northeast façade had two. The temporary protection and glazing replacement costs were significant.

For most of the southeast façade, very little wind and rain was driven into the offices. However, 

because of localized wind effects, some offices had significant amounts of rain and wind infiltration, which blew out ceiling boards and toppled office partitions. The MAT was advised that 

some furniture blew out of offices in this building and landed on the roof of the JP Morgan 

Chase Center across Travis Street. Because few of the broken windows were on windward façades, there was relatively little interior damage (Note: an explanation of the observed damage 

pattern is provided later in this section). 

Figure 5-7. 

Most of the glazing in the yellow oval was 

broken (JP Morgan Chase Tower). Inset 

shows location in cluster A; the yellow 

arrow shows the southeast façade where 

most of the damage occurred.

JP Morgan Chase Tower

JP Morgan Chase Tower

Texas Ave.

Capitol St.

Travis St.

Milam St.

Main St.
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 5-9

PERfORMANcE Of BuIldINGS IN HOuSTON'S cENTRAl BuSINESS dISTRIcT 5

JP Morgan Chase Center

The JP Morgan Chase Center utilizes single-pane, heat-strengthened glazing. Virtually all of the 

penthouse glazing and the glazing on the northwest façade, which was the windward side of the 

building during the time of the strongest winds (Figure 5-8), was broken. At least 16 windows 

were broken on the façade with the yellow arrow in Figure 5-8 inset. Only a few windows were 

broken in the opposite façade. There was no damage in the southeast façade.

The broken glazing on the northwest façade blew approximately 50 feet into the interior of the 

building. Once the exterior glazing was breached, wind-driven rain penetrated into the building, causing extensive interior damage. 

Figure 5-8. 

Northwest façade glazing damage on JP Morgan Chase 

Center. The broken windows at the office level are boarded 

up, but broken windows at the parking level are not. The blue 

arrow in the inset indicates the northwest façade; the yellow 

arrow indicates a façade that also received some damage.

The extensive glazing damage at the JP Morgan Chase Center, possibly in combination with 

some contribution from roof damage, allowed water penetration into the offices on Floors 

14 through 20, resulting in significant damage and loss of office space (Figure 5-9). On one 

of the floors, the MAT observed water damage that extended about 250 feet into the interior 

of the building. The water damaged interior walls and ceilings; some of the interior corridor 

walls toward the exterior fell over and touched the far wall. A computer lab, located along the 

exterior wall, received extensive water damage. Water damaged approximately 150 desktop 

computers. 

JP Morgan Chase Center

JP Morgan Chase Tower
5-10 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

5 Performance of Buildings in Houston's Central Business District

Cause of Glazing Damage in JP Morgan Chase Tower and Center

Although the glazing damage shown in Figures 5-7 and 5-8 is indicative of damage caused by 

windborne roof aggregate, the MAT conclusion is that aggregate did not, in fact, cause the damage based on the following observations:

Although aggregate-surfaced BURs were present on the buildings shown in the yellow and orange 

circles in Figure 5-10, it is unlikely that debris from these roofs caused the glazing damage observed at the JP Morgan Tower and Center. The 

wind direction and relatively low speed precluded aggregate from the roofs in the orange circle 

from being a debris source. The speed and direction may have been sufficient to cause aggregate 

to be blown from the penthouse of the building 

shown in the yellow circle of Figure 5-10 (and 

discussed in Section 5.2.4), but if that occurred, 

the aggregate would likely only have struck the JP 

Morgan Center façade, which had very little damage. MAT observations from a helicopter and the 

roofs of the Tower and Center did not reveal any 

other aggregate-surfaced roofs in the vicinity. 

Floors 18 and 19 sustained extensive damage. Water-damaged carpet and ceiling boards were 

removed from approximately 50 percent of the floor area that was observed by the MAT. At the 

time of the MAT observation, new materials were being installed, including new wiring, new 

data cables, and extensive HVAC work. Approximately 25 percent of the floor area on Floors 14 

through 17 sustained similar damage. 

OVERPRESSURIZATION

Wind speeds in downtown Houston during Hurricane Ike were below the ASCE 

7-05 design wind speed. Hence, glazing 

failure due to overpressurization via negative (suction) or positive loading would 

not be expected, unless the glazing was 

weakened by scratches, was inadequately designed for wind loads, or glazing or 

frame-capture of the glazing was inadequate to meet the wind loads.

Figure 5-9. 

View of repairs to an office 

damaged in the JP Morgan 

Chase Center
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 5-11

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The MAT postulates that the glazing damage occurred as a result of the following: some glazing 

in the Tower or the Center failed, either due to windborne debris or overpressurization, and the 

resulting glass shards became enveloped in vortices that developed between the two buildings. 

As the shards impacted the opposing façades, additional shards were injected into the vortices. 

It is believed that the vortices lifted the shards upwards, thereby causing damage at the upper 

floors (shown in Figure 5-11). Potential initial debris sources include trees along the sidewalks 

and metal wall panels from a nearby building (blue lines shown in Figure 5-10; refer also to Section 5.2.4).

The MAT’s postulate is consistent with initial research work on the observed glazing damage 

conducted by the University of Notre Dame in a paper titled Saga of Glass Damage in Urban Environments Continues: Consequences of Aerodynamics and Debris Impact During Hurricane Ike (Kareem, 

2008).2

 A model of the JP Morgan Tower and surrounding buildings was constructed and flow 

visualization experiments were conducted in a wind tunnel. In addition, flow visualization was 

analyzed by computational fluid dynamics (CFD). The wind tunnel and CFD studies both demonstrated that a series of vortical flow structures formed between the two façades that were 

heavily damaged (Figure 5-11). 

Figure 5-10. 

Locations of possible 

debris sources that 

impacted the JP Morgan 

Tower and Center. 

Aggregate-surfaced roofs 

within cluster A area 

shown by yellow circles. 

Blue lines show location of 

failed metal panel veneer.

SoURCE: NoAA, SEpTEMBER

17, 2008

2 Available at www.nd.edu/~nathaz/doc/NATHAZ_Ike_Glass_Dmg.pdf

JP Morgan Chase Tower

JP Morgan Chase Center

Texas Ave.

Capitol St.

Travis St.

Milam St.

Main St.
5-12 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

5 Performance of Buildings in Houston's Central Business District

Figure 5-11. 

The Tower is on the left and the Center 

is on the right. It is believed that vortices 

developed between these façades, and 

that glass shards entrapped within the 

vortices were slammed against and broke 

glazing in the opposing façades.

5.2.2 Granite Veneer 

At least two granite veneer panels on the southeast façade of JP Morgan Chase Tower were 

blown off. Stone fragments reportedly punctured the roof membrane on the JP Morgan Chase 

Center. The MAT observed a veneer panel on the southwest façade that remained in place, but 

had a notable debris impact scar. The cause of failure of the two panels may have either been a 

result of overpressurization (influenced by panel weakness or an installation deficiency) or they 

may have been broken by windborne debris. 

5.2.3 Roof Systems and Rooftop Equipment

According to project records, the original roof on the JP Morgan Chase Tower was a smoothsurface built-up roof over a concrete deck (Figure 5-12). It was reroofed in 1990 by fully adhering an EPDM3

 membrane directly to the BUR. The MAT did not observe any areas of membrane 

debonding or any damage to rooftop equipment. Some lightning protection conductors were 

3 Ethylene propylene diene monomer
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 5-13

PERfORMANcE Of BuIldINGS IN HOuSTON'S cENTRAl BuSINESS dISTRIcT 5

no longer held by some of the connectors, but it was not clear if the attachment was lost prior 

to or during the hurricane. 

A portion of the window washing equipment on the JP Morgan Chase Tower broke loose and 

slammed around, damaging the equipment (Figure 5-12 inset).

Figure 5-12. 

View of the JP Morgan 

Chase Tower roof. Inset 

shows damaged window 

washing equipment.

5.2.4 Nearby Building Performance 

There was variable performance of glazing and roof coverings at the surrounding buildings. 

Although some buildings were undamaged, several low-rise buildings had glazing and/or roof 

covering damage and one building had signage and wall covering damage. 

The roofs shown by the yellow arrows in Figure 5-13 had either been blown off (i.e., the tarped 

roofs) or punctured by windborne debris. Much of the roof puncture and glazing damage was 

likely caused by windborne glass shards. 

At the building shown in the bottom inset at Figure 5-13, concrete pavers had been installed 

around the perimeter of the main roof (solid green arrow at the inset) and at a portion of one 

of the penthouses as part of the original roof surfacing. However, the penthouse roof indicated 

with the dashed green arrow did not have pavers; its roof had a raised curb at the roof edge. Aggregate from this penthouse roof may have struck the side of JP Morgan Chase Center that had 

very little glazing damage.
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5 PERfORMANcE Of BuIldINGS IN HOuSTON'S cENTRAl BuSINESS dISTRIcT

Figure 5-14 is a view of the roofs in the white rectangle at Figure 5-13. Blue and clear plastic tarps 

cover two roof areas. The green arrows show where an aggregate-surfaced built-up membrane 

lifted and peeled back. It is doubtful that aggregate from these roofs struck the JP Morgan 

Chase Tower or Center buildings. The punctured roof with the black arrow is the same as shown 

at the top inset of Figure 5-13. Several windows were broken in the buildings shown by the yellow arrows.

Figure 5-15 shows a building that lost several metal wall panels and a wall-mounted sign; the inset shows the building location and the façade that lost the panels (blue lines). It appears that 

the wall panel debris had the potential to strike either the JP Morgan Tower or Center.

In addition to the damage described above, the MAT observed a mid-rise building that had a 

protected membrane roof system that used extruded polystyrene insulation boards with a cementitious coating for the ballast. On-the-roof observation was not made, but analysis of high 

resolution photographs did not reveal any wind uplift problems.

Figure 5-13. 

The main roof of the JP Morgan Chase Center (blue 

arrow) and several other roofs (indicated by yellow 

arrows) were blown off or damaged by debris. Black 

areas at the top inset are patches. The bottom inset 

shows a building with built-up aggregate-surfaced 

roofs. The location inset shows the buildings in this 

figure (yellow box). See Figure 5-14 for the buildings in 

the white rectangle.

Penthouse

Texas Ave.

Capitol St.

Travis St.

Milam St.

Main St.

Capitol St.

JP Morgan Chase Center
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 5-15

PERfORMANcE Of BuIldINGS IN HOuSTON'S cENTRAl BuSINESS dISTRIcT 5

Figure 5-14. 

Glazing damage (yellow 

arrows) at two of the 

buildings shown in the 

white rectangle in Figure 

5-13. The blue, green, 

and black arrows indicate 

damaged roofs.

Figure 5-15. 

Several metal panels blew off of two façades of this 

building, along with a wall-mounted sign (yellow arrow). 

Two broken windows can be seen in the yellow circle at the 

JP Morgan Chase Tower. Inset shows location of building 

(yellow box); blue lines indicate façades where metal panels 

blew off.

JP Morgan Chase Tower

Texas Ave.

Capitol St.

Travis St.

Milam St.
5-16 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

5 PERfORMANcE Of BuIldINGS IN HOuSTON'S cENTRAl BuSINESS dISTRIcT

Loss of Function

The upper floors of JP Morgan Chase Center, Floors 14 through 20, were not operational for a 

substantial amount of time. The cost of the repairs is expected to be around $3.1 million. At the 

time of the MAT observation, the cleanup and repair crews had been at the building for about 

2 months. In addition to cleanup costs, costs were incurred by the resulting loss of function of 

the offices. Some of the office functions were moved out of the State. 

5.3 Cluster B – Chevron Center Area

An enlarged view of cluster B from Figure 5-1 is shown in Figure 5-16. The Chevron Center is 

part of cluster B. This 40-story building was built in 1999–2002. A large number of windows were 

broken on the side indicated by the yellow arrow in Figure 5-16 (refer also to Section 5.3.1). The 

roof membrane was blown off the end of the building indicated by the green arrow (refer also 

to Section 5.3.2). The building lost power during Hurricane Ike and for 2 days afterward. 

Figure 5-16. 

A substantial amount of 

glazing damage occurred 

to the façade of the 

Chevron Center, indicated 

by the yellow arrow. The 

roof membrane blew 

off from the end of the 

building (green arrow). 

The red arrows show 

Hurricane Ike’s primary 

wind directions and 

maximum gust speed for 

the given direction. 

SoURCE: NoAA, SEpTEMBER

17, 2008

66 mph Chevron Center

Texas Ave.

Travis St.

Main St.

Milam St.

Louisiana St.

Smith St.
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 5-17

PERfORMANcE Of BuIldINGS IN HOuSTON'S cENTRAl BuSINESS dISTRIcT 5

5.3.1 Glazing

The area of the Chevron Center that received most of the glazing damage is shown in Figure 

5-17. The outer panes of about 700 heat-strengthened windows were broken. At seven windows, 

both the inner and outer lites were broken. 

Shortly after the storm, the building owner retained a company to quickly install a temporary 

film over all of the broken glazing as a safety precaution to avoid falling shards of glass (Figure 

5-18). Once the protective film was in place, work commenced on removing the broken glass 

that was still in place. Glass removal took considerable time, hence the initial installation of the 

protective film was prudent to protect pedestrians. 

Chevron Center

Figure 5-17. 

Chevron Center glazing damage. At the building beyond (yellow circle), at least 35 windows were boarded up. 

Bottom inset shows location. 
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Cause of glazing damage: Prior to and during the MAT helicopter observations, the glazing 

damage at the Chevron Center had not been detected. Therefore, the high-rise roofs near the 

Chevron Center were not observed during the flight for potential debris sources. Subsequent 

analysis of the NOAA high-resolution photographs did not reveal an obvious debris source. 

Roof debris from the building designated as B-1 in Figure 5-19 (close up view shown in Figure 

5-28) appears to have had the potential to strike the center area of the Chevron Center. Although some glazing damage occurred in the center area, the damage was primarily near the 

end of the Chevron Center. Also, when the wind was blowing in the direction conducive for 

roof debris from building B-1 to strike the Chevron Center, the wind speed was relatively low. 

Therefore, roof debris from building B-1 is not believed to be the primary cause of the Chevron 

Center glazing damage.

Figure 5-18. 

Broken glazing held in place with 

temporary film
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 5-19

PERfORMANcE Of BuIldINGS IN HOuSTON'S cENTRAl BuSINESS dISTRIcT 5

The LPS conductor around the perimeter of the Chevron Center detached from the conductor 

connectors. It is conceivable that the conductor dangled over the side of the building (similar to 

that shown in Figure 4-40) and caused some glazing damage. Also, as discussed in Section 5.3.2, 

some of the lightweight insulating concrete roof deck blew off and landed on a roof area that 

was just a few floors below the main roof. It is conceivable that some of the deck debris caused 

some glazing damage.

Additional study, which is beyond the scope of the MAT, is needed to more definitively assess the 

primary cause of glazing damage on this building.

Chevron Center

B1

Chevron Center

Figure 5-19. 

Portions of the roof system were blown off building B-1. 

Winds blowing roof debris in the direction shown by the long red 

arrow may have had potential to strike the Chevron Center. The green 

arrow indicates where a portion of the roof membrane blew off the 

Chevron Center. The yellow arrows at the inset show locations of buildings that had aggregate-surfaced roofs. 

SoURCE: NoAA, SEpTEMBER 17, 2008

Texas Ave.

Travis St.

Milam St.

Louisiana St.

Smith St.

Two mid-rise buildings with aggregate-surfaced BURs occur to the south of the Chevron Center 

(yellow arrows at the inset of Figure 5-19). These buildings are shown in Figure 6-4. The closest 

building is approximately 250 feet from the Chevron Center, which is well within the flight capability 

of windborne aggregate. However, wind direction during Hurricane Ike precluded aggregate from 

these buildings as being potential debris sources for the glazing damage at the Chevron Center (refer to red arrows indicating wind directions shown on Figure 5-19). 
5-20 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

5 PERfORMANcE Of BuIldINGS IN HOuSTON'S cENTRAl BuSINESS dISTRIcT

5.3.2 Roof Systems and Rooftop Equipment 

The perimeter of the Chevron Center roof had a PVC membrane fully adhered to lightweight 

insulating concrete. The main roof is surfaced with 16-inch by 16-inch lightweight interlocking 

concrete pavers. 

A portion of the PVC roof membrane was blown off in the vicinity shown by the green arrow 

in Figure 5-19 and as shown in Figure 5-20. The concrete deck was gouged in many locations 

(Figure 5-20). The gouging may have been due to roof membrane flutter, or it may have been 

caused by the detached lightning protection conductor.

Figure 5-20. 

The lightweight insulating 

concrete deck was gouged 

in many locations

As a result of the roof membrane damage, the window washing track (Figure 5-21) was damaged. Apparently, membrane fluttering caused the nuts on the 1⁄2-inch stainless steel bolts to 

loosen. The galvanized T-shaped window washing track is 4 inches high and 5 1⁄2 inches wide, 

with a 1⁄4-inch thick head and a 3⁄8-inch stem. 
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 5-21

PERfORMANcE Of BuIldINGS IN HOuSTON'S cENTRAl BuSINESS dISTRIcT 5

5.3.3 Damage at Nearby Buildings

In addition to the glazing and roof covering damage at the Chevron Center, several other low-, 

mid-, and high-rise buildings shown in Figures 5-22 and 5-23 had various types of building envelope damage as described below. 

Figure 5-21. 

View of the damaged 

window washing track 

(green arrow). The 

concrete pavers (blue 

arrow) were not damaged.

Figure 5-22. 

Locations of nearby 

damaged buildings 

SoURCE: NoAA, SEpTEMBER

17, 2008

66 mph Chevron Center

B1 B2

B3

B5

B4

Texas Ave.

Travis St.

Main St.

Milam St.

Louisiana St.

B3 Smith St.
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5 PERfORMANcE Of BuIldINGS IN HOuSTON'S cENTRAl BuSINESS dISTRIcT

The view in Figure 5-23 is looking northeast from the roof of the Chevron Center. Yellow arrows 

indicate two broken windows in the high-rise beyond. There was extensive roof covering damage at building B-3, including exterior wall collapse (green arrow). 

Figure 5-23. 

View of buildings with 

glazing, roof and wall 

covering, and rooftop 

equipment damage

At building B-2, as shown in Figure 5-24, there was roof puncture damage at the three roof areas shown by the blue arrows, metal wall panels were blown off (yellow arrow), skylights were 

damaged (green arrow), and a fan cowling was blown off the upper round roof. According to a 

Hurricane Alicia investigator, this building experienced similar damage during that hurricane. 

Building B-5 had an aggregate-surfaced BUR with low parapets (likely less than 12 inches high). 

The aggregate from this roof was a debris source for the building B-4 glass damage (Figure 5-25; 

close-up shown in Figure 5-26). The red arrow in Figure 5-25 indicates the generalized likely 

flight path of the aggregate debris. At least two fan cowlings blew off the building B-5 roof. On 

the back side of building B-5, a few stone veneer panels were damaged (Figure 5-27). According 

B2

B3

B5

B4
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 5-23

PERfORMANcE Of BuIldINGS IN HOuSTON'S cENTRAl BuSINESS dISTRIcT 5

Figure 5-24. 

Roof and wall covering, 

skylight, and roof-top 

equipment damage at 

building B-2

Figure 5-25.

Roof aggregate from 

building B-5 was the 

likely cause of the 

majority of the building 

B-4 glass damage. The 

area in the yellow box is 

shown in Figure 5-26. 

B5

B3

B2

B1

B4

B2
5-24 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

5 PERfORMANcE Of BuIldINGS IN HOuSTON'S cENTRAl BuSINESS dISTRIcT

Figure 5-26. 

View of the aggregate-surfaced roofs on building B-5 and broken glazing on building B-4 beyond. Red arrows 

indicate generalized aggregate flight path. The yellow arrow shows a penthouse door that blew off. Inset shows 

damage on a portion of building B-4 below the area shown in the main photograph.

Figure 5-27. 

Stone veneer damage on backside of 

building B-5 (side facing B-4)
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 5-25

Performance of Buildings in Houston's Central Business District 5

to a Hurricane Alicia investigator, buildings B-4 and B-5 had somewhat similar damage during 

that hurricane. However, the rooftop penthouse performance on building B-5 was better during Hurricane Ike.

Figure 5-28 shows roof covering damage to building B-1, which was a possible debris source for 

some of the glazing damage to Chevron Center, as discussed in Section 5.3.1. This building is 

one of the oldest high-rise buildings in the downtown area.

Figure 5-28. 

Roof covering damage on 

the main and penthouse 

roofs of building B-1 

5.4 Vegetative Roofs

In the downtown area, the MAT observed three vegetative roofs (also known as garden roofs 

and green roofs). Vegetative roofs had not been observed by previous MATs. The MAT is not 

aware of previous documentation of wind performance of vegetative roofs. Currently, there are 

no consensus wind design guides or wind-related code requirements for this type of roof.

Vegetative roofs can either be “extensive” (with very low plants) or “intensive” (which allows for 

the planting of shrubs and trees). All three of the vegetative roofs observed by the MAT had 

trees, as shown in Figure 5-29. The MAT did not perform on-the-roof observations at any of the 

vegetative roofs, but it was apparent that few, if any, tree limbs were blown away. Lack of limb 

damage may have been prevented by sheltering from nearby buildings. Also, the low-level wind 

speeds in the downtown area were not sufficiently high to cause substantial loss of limbs. The 

concern with limbs is their potential to damage glazing if they are blown away, particularly when 

trees are placed many floors above grade.
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5 PERfORMANcE Of BuIldINGS IN HOuSTON'S cENTRAl BuSINESS dISTRIcT

Figure 5-29. 

View of a vegetative roof 

in the downtown area 
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 6-1

CONCluSIONS 6

Conclusions

The conclusions presented in this report are based on the MAT’s 

observations in the areas studied; evaluations of relevant codes, 

standards, and regulations; and a meeting with State and local 

officials, business and trade associations, contractors, and other 

interested parties. These conclusions are intended to assist the States 

of Texas and Louisiana, communities, businesses, and individuals 

in the reconstruction process, and to help reduce future damage 

and impacts from flood and wind events similar to Hurricane Ike. 

The report and recommendations will also help FEMA assess the 

adequacy of its flood hazard mapping and floodplain management 

requirements, and determine whether changes are needed or 

additional guidance is required.

6Conclusions
6-2 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

6 Conclusions

The conclusions presented in Sections 6.1 (residential), 6.2 (critical facilities), and 6.3 (Houston’s Central Business District) relate to recommendations made in Section 7 to ensure that 

designers, contractors, building officials, and coastal populations understand what is necessary 

for disaster-resistant construction in hurricane-prone regions.

6.1 Residential

6.1.1 Flood

Flood-related damage was severe and widespread, especially along the Texas shoreline east of 

the entrance to Galveston Bay. High storm surge levels, waves, scour and erosion, and floodborne debris contributed to the damage. 

On Bolivar Peninsula, wave damage to floor systems of surviving homes revealed that wave crest 

elevations probably reached 2 to 5 feet above the BFE. Along western Galveston Island and 

along Follets Island, wave crest elevations appear to have been below the BFE. Flood levels in 

some communities adjacent to Galveston Bay or Sabine River were several feet above the BFE. 

In southwest Louisiana and in the Sabine Pass region of Texas, flood levels were above Hurricane Rita elevations in many places, below in others, but were generally above BFEs shown on 

FIRMs. 

The MAT observed a much greater incidence and severity of scour around Gulf-front building 

foundations during Hurricane Ike than during other recent Gulf coast hurricanes (e.g., Opal, 

Ivan, and Katrina). The reason for the prevalence and magnitude of foundation scour during 

Ike is not known at this time.

Most structural failures observed by the MAT and associated with flooding appeared to be the 

result of one or more of the following: inadequate elevation of the building, inadequate pile 

embedment, unanticipated levels of scour and erosion around the foundation, improper load 

path connections from the elevated building to the foundation to the ground, or inadequate 

foundation resistance to flood loads. 

Building Elevation Relative to Flood Level. Flood damage to buildings was generally consistent with 

expectations, given the observed flood levels. Flood damage to commercial facilities was generally similar to flood damage at nearby residential structures. 

1. In areas where flood levels exceeded the BFE, newer construction elevated several 

feet above the BFE on strong foundations generally survived with little flood damage, 

except in instances where unanticipated scour or floodborne debris led to foundation 

failures. Nearby newer construction elevated only to the BFE was heavily damaged or 

destroyed. Older, lower construction was often damaged or destroyed as well. 

2. In areas where flood levels were below the BFE, flood damage to NFIP-compliant 

buildings was generally minimal, with a few exceptions where scour and erosion or 

foundation-related deficiencies led to damage.
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 6-3

Conclusions 6

3. In areas subject to Coastal A Zone conditions during Ike, apparently compliant Zone A 

construction was sometimes damaged by waves and velocity flow. The NFIP practice of 

allowing construction of floor systems below the BFE leads to building damage.

4. Buildings behind the Galveston seawall were subject to flooding from Galveston Bay 

and to Gulf-side flooding due to wave overtopping, but were not exposed to direct wave 

attack.

Buildings that were built according to minimum standards and code, with the lowest floor elevation at the BFE, sustained significant damage or destruction when the flood level exceeded 

the BFE. 

Many houses were elevated to the BFE and survived Ike—they were not subject to base flood 

or design wind conditions during the storm. However, some of these houses will fail if they are 

ever subject to base flood conditions or design winds. The MAT observed houses that were not 

attached to their foundations or were elevated on foundations that lacked load path continuity 

to the ground. This problem was also noted in cases where the MAT observed houses in Louisiana that were elevated with Federal funds, including HMGP grants and flood policy Increased 

Cost of Compliance payments.

Several houses visited by the MAT in Galveston County were advertised as, or known to be, enhanced code construction (refer to Section 2.4 for discussion of enhanced code construction). 

While it is true that these houses were elevated above the BFE and incorporated certain wind-resistive features that exceeded code requirements, some of these houses sustained flood damage. 

The flood damage observed by the MAT was typically a result of scour and erosion exceeding 

the ability of the pile/column foundation to remain vertical, or lateral loads and bending moments exceeding the material properties of the foundation piles/columns.

The Federal Communications Commission studied communications related to response activities following Hurricane Katrina; this study included a consideration of emergency power 

requirements for cell towers. The MAT noted and benefited from the elevation of cell phone 

tower equipment and powering by emergency generators on Bolivar Peninsula (Figure 6-1). 

When the MAT was in the field 5 days after Hurricane Ike, it had cell phone coverage and was 

able to access maps and other information from the Internet, despite the fact that much of the 

commercial and residential development on the Peninsula lay damaged or in ruins.

Foundation Design. Based on the failures observed by the MAT, foundation design does not receive adequate attention from design professionals. Specifically, the MAT observed:

1. Some buildings exposed to severe foundation scour collapsed, some suffered 

differential settlement, and some survived without damage. 

2. Some buildings were elevated above the BFE and would have been expected to 

survive Ike’s flood loads and conditions without damage. However, the MAT observed 

connection failures or bending failures in piles and columns that led to collapse of 

otherwise successful buildings.
6-4 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

6 Conclusions

Figure 6-1. 

Two examples of elevation of equipment 

above grade on pile/column foundations, 

a good practice that ensured continuity of 

cell phone service on Bolivar Peninsula, TX

Parking Slab Failures. The MAT observed a wide range of parking slab performance, and a range 

of slab effects on foundation performance. 

The MAT observed instances where parking slab failures led to timber pile failures at elevated 

houses. Where broken slabs remained connected to foundation piles, they transferred loads to 

the piles that the piles could not resist—racked foundations and broken piles resulted. Some 

people might argue that constructing thicker and stronger slabs would prevent this problem, 

but the MAT also observed instances where intact parking slabs beneath elevated houses appeared to contribute to foundation and building settlement by increasing scour around the 

foundation (as water flowed between the bottom of the slab and the eroded ground) and by 

placing additional vertical load on the foundations. Foundation success requires adequate 

embedment into the ground, after accounting for erosion and scour; while a slab may help to 

stiffen a foundation, it is not a substitute for adequate embedment. 

The MAT also observed instances where unreinforced, frangible slabs had been constructed 

beneath elevated houses, in conformance with Galveston County requirements. These slabs 

collapsed, as intended, with no apparent harm to the elevated houses or their foundations. 
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 6-5

Conclusions 6

Siting. MAT observations regarding siting effects on building damage were consistent with observations following past storms. Buildings situated the closest to the Gulf of Mexico shoreline, 

either by intent or because of long-term erosion effects, are at greatest risk to erosion and wave 

effects and sustained the greatest damage during Ike. While building elevation and foundation 

strength can overcome some of the risk associated with siting a building close to the shoreline, 

typical design practice cannot compensate for prior land planning and development decisions 

that result in small lots close to an eroding shoreline. 

Breakaway Wall Performance. Generally, solid breakaway walls performed as expected—they 

broke free when subjected to lateral flood loads. However, below-BFE elements constructed of 

lattice or louvers may be preferred over solid breakaway wall panels. While the latter tended 

to break away (as designed) when exposed to flood depths of a few feet and small waves, the 

louver and lattice wall panels, subjected to the same flood conditions, allowed water to flow 

through the panel without damage to the panel or building, thereby reducing repair costs for 

the owner.

As homes are elevated to higher and higher elevations above the BFE (which FEMA encourages), one unintended consequence is that breakaway wall panels are becoming taller and taller, 

resulting in larger and larger floodborne debris elements. 

Manufactured Homes. Manufactured homes generally performed in a manner consistent with 

their performance in prior storms. Those that were elevated on strong foundations and tied 

down to resist wind effects survived intact as long as flood levels remained below the chassis 

frame and wind speeds were low. Those not installed and restrained on adequate foundations 

were damaged or destroyed once flood levels reached the floor system. Those homes not properly tied down often shifted due to lateral wind loading. 

In some locations in Louisiana, manufactured housing installed after Hurricane Rita was not 

elevated at or above the BFE. This may have occurred in existing manufactured housing parks 

where an NFIP exception allows homes to be elevated 3 feet above grade, even where this 

is lower than the BFE, or it may have occurred through incorrect application of the 3-foot 

exception. Whether this was allowed by the NFIP exception or not, the result was the same—

manufactured housing installed below the BFE after Hurricane Rita was completely destroyed 

by Hurricane Ike.

6.1.2 Wind

The observed and modeled wind speeds of Hurricane Ike were less than the design wind 

speeds required by ASCE 7-05 for the areas of Texas and Louisiana affected by the storm. Damage to buildings and other structures was therefore generally associated with wall cladding and 

roofing materials.

Due to Ike’s lower wind speeds, most of the homes were spared the devastating high wind pressures that cave in walls and doors, and remove large sections of roofs. The observed damage from 

Ike related to debris impacts and wind pressures appeared to be the result of the use of building 
6-6 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

6 Conclusions

products not intended for hurricane-prone regions, poor installation practices, and poor code 

enforcement, all of which are correctable. In Texas, where specific independent review and inspection practices were provided by TDI, the required construction practices were well understood 

and complied with by the builders. However, questionable building practices of new construction 

in unincorporated areas that fall within the purview of the TRCC was observed.

Roof Systems. In the areas observed by the MAT, roof covering damage was common and quite 

variable, which is consistent with what was observed by the Hurricanes Charley, Ivan, and Katrina MATs (see FEMA 488, 489, and 549).

n Very little sheathing damage was observed. However, the damage observed was related to 

unsupported large overhangs and poor construction practices.

n Roofing damage to older homes appeared to be a function of the age of the roof, whereas 

roofing damage to newer homes was a function of poor installation and failure to follow 

guidelines for installations in high-wind zones.

n Several houses visited by the MAT in Galveston County were advertised as or known to be 

enhanced code construction. While it is true that these houses were elevated above the 

BFE and incorporated certain wind-resistive features that exceeded code requirements, 

some of these houses sustained wind damage. The wind damage observed by the MAT was 

typically roof covering loss, roof sheathing loss, or water penetration through soffits and 

vents or around windows and doors.

Non-Load-Bearing Walls and Wall Coverings. An extensive amount of wall covering was damaged 

by Hurricane Ike. The majority of this damage was to vinyl siding and fiber cement siding. In 

most cases, the failures were related to installation of products not rated for the high-wind 

zones and installers not utilizing industry recommendations for high-wind zone installations. It 

was further observed that some cladding failures associated with attics were related to the use 

of sheathing that was not attached in accordance to high-wind zone procedures. These attachment failures made the sheathing/cladding system incapable of independently withstanding 

design wind pressures behind the system, which led to failures.

Doors, Windows, and Shutters. Few impact-resistant glazed window units were observed by the 

MAT. Most houses observed by the MAT had some form of shutter to provide debris impact 

protection. The shutter type varied from simple plywood to expensive roll-down shutters. The 

MAT observed numerous instances where plywood shutters were not properly anchored to 

the building structure, but rather to window frames and wall cladding. Though few debris impacts were observed, it appeared that most shuttering was effective in this less-than-design wind 

event. It was further observed that some homeowners chose not to shutter all windows (Figure 

6-2). In some instances, shutters were only placed on the seaward facing windows, and the unshuttered north facing windows left vulnerable to Ike’s backside winds.
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 6-7

CONCluSIONS 6

Figure 6-2. 

The upper windows 

on this Seabrook, TX, 

residence were not 

shuttered and were 

vulnerable to windborne 

damage

Roof Soffits, Fascias, and Gable Vents. The MAT observed many instances where vinyl soffits and 

aluminum fascia covers failed, thereby allowing water infiltration into the homes, resulting in 

damage. At least one gable end vent was observed to have blown from its mounting. All of these 

failures appeared to be installation issues. 

Exterior-Mounted Equipment. All observed HVAC units mounted on the outside of the homes were 

elevated, per the guidelines contained in FEMA 55.
6-8 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

6 Conclusions

6.2 Critical Facilities

6.2.1 Flood

Critical facilities generally performed as expected. Those that were elevated higher than the 

minimum permitted elevation and on stronger foundations sustained less damage to structural 

and non-structural components. Those that were constructed in a manner similar to nearby, 

minimally compliant residential and commercial structures sustained more damage. 

Building Elevation Relative to Flood Level. At least one critical facility, a hospital destroyed by Hurricane Rita and rebuilt prior to Ike, does not appear to have sufficient elevation and will likely be 

flooded again. The facility was rebuilt with the top of its lowest floor 1 foot above the BFE. While 

Ike flooding did not enter the building (the flood level was reported to be just a few inches below the floor’s walking surface), below-floor utilities were damaged by Ike and facility function 

was lost for a period of time. Critical facilities such as this should be elevated such that the floor 

system and all below-floor utilities are several feet above the BFE to reduce the likelihood of future flood damage and loss of facility use. 

Another critical facility—a relatively new jail and criminal justice complex—was flooded during Hurricane Rita and was flooded again during Ike (18 to 24 inches of flooding was reported 

during Ike). The electronic equipment and controls for the jail security and communications 

systems were damaged during both Rita and Ike, and prisoners had to be transferred temporarily to a State facility. The 1985 FIRM (the most recent FIRM at the time of construction) showed 

the site in Zone C (outside the 500-year floodplain). This example points out that flood hazard 

evaluations for proposed critical facilities should involve more than reading an old FIRM; designs for proposed critical facilities should involve a careful assessment of potential damage and 

operational interruptions in the event that flooding exceeds the flood level shown on the FIRM. 

Self-audit guidelines have been published for existing correctional facilities and could also be 

used to help inform siting and design decisions for proposed facilities. 

Given the nature of critical facilities, a higher level of flood protection is needed. Loss of facility function due to flood damage can have far-reaching consequences for community response, 

recovery, and reconstruction. ASCE 7-05 and ASCE 24-05 designate jails and detention facilities 

as Category III facilities, which require additional design consideration beyond building code 

requirements for typical commercial and residential construction. Correctional facilities should 

be located outside the floodplain or elevated to the 500-year flood elevation. If 500-year flood 

elevations are not available, elevate above the BFE with sufficient freeboard to prevent damage and loss of use. Some States have mandated special permit requirements and freeboard for 

correctional facilities located in or near flood hazard areas (e.g., Commonwealth of Pennsylvania, 2001). Federal agencies with involvement in funding, permitting, and constructing critical 

facilities are required to adhere to the requirements of Executive Order 11988, Floodplain 

Management (refer to Section 4.0 for additional information).

Equipment and Utilities. Critical facilities with equipment and utilities in basements, at ground level, or above ground but below the flood level, sustained flood damage to these support systems 
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 6-9

Conclusions 6

that either prohibited post-Ike resumption of operations, or delayed or reduced operational 

capabilities. 

Mitigation Project Performance. The MAT observed critical facilities that had received Federal 

mitigation grant funds to address previous damage or known vulnerabilities. However, the mitigated facilities were still vulnerable, either to the hazard against which they had presumably 

been mitigated, or against other hazards. 

6.2.2 Wind

All of the critical facilities exposed to Hurricane Ike were subjected to wind speeds that were 

less than the design wind speeds given in ASCE 7-05. Hence, while most of the critical facilities 

observed by the MAT experienced relatively little or no wind damage, had Hurricane Ike delivered current design wind speeds, poor wind performance would have been likely at many of 

the facilities. 

Many critical facilities in the area impacted by Hurricane Ike (as well as in other hurricaneprone regions of the United States and its Territories) have significant wind vulnerabilities and 

are therefore in need of mitigation. This is particularly the case with those facilities older than 

10 to 15 years, when codes, standards, design, and construction practices did not adequately 

address wind, windborne debris, and wind-driven rain issues. Older buildings with significant 

vulnerabilities were observed by the Ike MAT. 

The recommendations in FEMA 424, Design Guide for Improving School Safety in Earthquakes, 

Floods, and High Winds (January 2004), FEMA 543, and FEMA 577 were largely based on field 

observation research. The research was conducted on numerous critical facilities that were 

struck by nine hurricanes dating back to 1989. The buildings were exposed to wind speeds 

ranging from around 100 to 160 mph (peak gust, Exposure C at 33 feet). The majority of that 

research was conducted by FEMA teams. None of the Hurricane Ike MAT observations refuted 

the recommendations in FEMA 543 or 577. Hence, it is still believed that the recommendations 

in these design guides are valid. (Note: The wind recommendations in FEMA 424 are out of 

date—refer to the wind chapter in FEMA 543 for more current guidance on schools.) 

The Hurricane Ike MAT observations revealed issues that led to new recommendations in Section 

7.3 regarding roof drainage, flexible ductwork 

connectors, and emergency generators.

Emergency Generators. Maintaining adequate 

power during and after a hurricane is vital to the 

functioning of many critical facilities. The Ike 

MAT observed several notable deficiencies.

Location and Protection. In general, the MAT 

observed a lack of protection of emergency 

In addition to providing redundancy for 

the emergency generator, another advantage to a back-up generator is that it 

can be sized to carry electrical loads that 

are truly needed for long-term functioning 

of a facility. For example, at the hospital 

discussed in Section 4.2.2, the emergency generator only carried the minimum 

loads required by code—the generator 

did not power the HVAC system.
6-10 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

6 CONCluSIONS

For critical facilities where a total loss of power for several days is tolerable (for instance, a 

community center that serves to house emergency workers brought in after a storm), it can be 

appropriate to save money and locate the generator outdoors. For facilities where loss of power 

is not tolerable (such as hospitals and EOCs), however, it is very unwise to place them outdoors 

or in enclosures that lack sufficient wind and windborne debris resistance. 

Generator Capacity and Redundancy. Code requirements for emergency generators generally provide adequate capacity for life-safety equipment, essential equipment, and power required for 

the orderly shut-down of critical operations. However, the amount of emergency power required 

for a facility to provide needed services during a prolonged power outage generally exceeds that 

dictated by code. For critical facilities where power for some services cannot be interrupted 

(such as hospitals and EOCs), additional generator capacity, beyond that dictated by code, is 

needed. For example, most codes and standards do not require air conditioning to be powered 

by emergency generators. However, temperature and humidity levels can rise rapidly in critical 

facilities located in hurricane-prone regions if air conditioning equipment is not supplied by 

emergency power, thereby preventing performance of many critical functions. 

generators from wind and windborne debris at the vast majority of critical facilities that were 

observed. The majority of the generators were located outdoors and were susceptible to wind 

and windborne debris damage. For critical facilities that need to be operational during a hurricane, it is beneficial to house the generators within a building. The advantage of doing so is that 

if there is an equipment failure, repairs can be performed during the storm. Conversely, when 

generators are located outdoors, it is often unsafe to work on them during an event. Also, when 

housed within a building that is resistant to wind, windborne debris, and tree-fall (as recommended in FEMA 543 and 577), the generator is protected from these hazards (Figure 6-3). 

Figure 6-3. 

The tree shown by the 

red line nearly fell on the 

hospital’s emergency 

generator (red arrow). 

The tree hit and damaged 

a metal roof that was 

over the compressed gas 

cylinders (blue arrow).
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 6-11

Conclusions 6

For critical facilities that must remain operational during prolonged power outages, 

provisions should be made to supply adequate 

generator power for operations during and after 

a hurricane. Providing power from two or more 

generators offers benefits and should be considered for critical facilities where loss of power 

is not tolerable. However, for critical facilities 

where loss of power for several days is tolerable, 

it can be appropriate to save money by not installing multiple generators. 

Having multiple generators provides several advantages. When power is supplied from multiple 

generators, each generator is not a redundant 

back-up unit, but rather a power source that can be operated alone or in conjunction with other 

generators to provide power. In addition, having multiple generators improves reliability. During 

an event when municipal power is disrupted, facilities with two or more emergency generators 

do not have to rely on a single unit for emergency power. This is especially important during 

long-duration outages that can overstress generators designed for periodic short-duration operation. Having multiple emergency generators also facilitates maintenance, as individual units 

can be taken out of service to perform periodic maintenance without denying the facility its 

emergency power source. 

When a facility has only one generator, the facility will be left without power if there is loss of 

municipal power and if the sole emergency generator fails. This scenario occurred at a hospital 

observed by the Ike MAT. With the failure of the single emergency generator, the entire facility 

had to be evacuated for 4 days until a temporary portable generator could be brought to the 

site. The MAT observed only a few critical facilities that had multiple generators.

Aggregate-Surfaced Roofs. The MAT observed some critical facilities (including a hospital and 

nursing home) that had aggregate-surfaced roofs. Even winds of about 100 mph (peak gust, Exposure C at 33 feet) are sufficient to blow aggregate from BURs with sufficient momentum to 

break glazing. Also, windborne aggregate can pelt people arriving at shelters or hospitals during a hurricane. Even though the potential hazard of windborne aggregate is well documented 

and significant, many owners of critical facilities apparently fail to understand the importance 

of mitigating this potential hazard.

Mitigation Project Performance. All of the HMGP work observed by the MAT failed to address all 

wind vulnerabilities. In seeking to reduce damage from hurricanes, building owners do not always 

understand or address all the vulnerabilities of the building. The MAT observed many instances 

where only some of the building’s vulnerabilities to disaster damage had been addressed. 

The MAT observed a number of buildings where mitigation projects had been accomplished 

that addressed one vulnerability but left other vulnerabilities unaddressed. Obviously, before 

To help ensure the reliability of emergency and back-up power, it is important that 

generators be well maintained and tested frequently. Also, for critical facilities 

that need to be functional during a hurricane, it is important to have maintenance 

personnel on site during the event so that 

if the emergency power generation system malfunctions, repairs can commence 

immediately. For example, on-site maintenance personnel were instrumental in the 

quick restoration of emergency power at 

the EOC discussed in Section 4.3.1.
6-12 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

6 Conclusions

implementing a mitigation project, it is important to fully evaluate vulnerabilities. While it may 

not be appropriate to address all of the significant vulnerabilities, if all vulnerabilities are not 

mitigated, that decision should be a conscious one based on deliberation and consideration of 

residual risks.

The MAT also observed a lack of thoroughness and robustness in mitigation efforts. For example, putting on a new roof system that lacks a secondary membrane or reroofing work that 

does not adequately anchor rooftop equipment. Roof membranes are frequently punctured by 

windborne debris. When this occurs, water will leak into the building unless a secondary membrane is incorporated into the roof assembly. Blow-off of rooftop equipment also frequently 

occurs and results in water leakage. 

Prior to the publication of FEMA 543 and 577, there was very limited design guidance on mitigating wind vulnerabilities. Hence, those HMGP projects that were implemented before these 

guides were published were handicapped by lack of guidance. However, with the publication 

of FEMA 543 and 577, there are extensive recommendations on a variety of issues. Some of the 

recommendations are quite conservative, and in some cases it could be appropriate to not implement all of them. However, if a FEMA 543 or 577 recommendation is not implemented, that 

decision should be based on deliberation and consideration of residual risks. 

6.3 Houston’s Central Business District

The MAT observed various types of building envelope damage at several buildings in Houston’s 

central business district. Although Hurricane Ike’s winds were not as high as the current design 

wind speed, some buildings received extensive exterior envelope damage, particularly to glazing and roof coverings. 

Aggregate-Surfaced BURs. Twenty-five years ago, aggregate blow-off during Hurricane Alicia 

caused extensive and expensive glazing damage in Houston. Therefore, it was surprising to observe that there were still aggregate-surfaced BURs in the area (see Chapter 5). Because wind 

speed increases as the roof height increases, the risk of aggregate blow-off also increases with 

roof height. It was therefore particularly surprising to observe aggregate surfacing on mid-rise 

buildings (such as those shown in Figure 6-4), where their presence presents enhanced opportunity for damage to surrounding buildings. 

To avoid aggregate-induced glazing damage in urban areas in hurricane-prone regions, aggregate should be removed from built-up and sprayed polyurethane foam roofs. 
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 6-13

CONCluSIONS 6

Pedestrian Protection. In downtown Houston, the MAT observed remnants of unprotected broken glass several floors above grade at a few buildings (as illustrated by the inset at Figure 5-26). 

Those remnants had the potential to be dislodged during light winds and cause injury. At the 

time of the observations, many pedestrians were in the area. However, some building owners 

had taken quick action to mitigate the injury potential. For example, as discussed in Section 

5.3.1, one building owner retained a company to install temporary film over the broken glazing 

as a safety precaution to avoid falling shards of glass. That appeared to be a prudent course of 

action. Boarding up windows can also be effective, provided it is done before people return to 

the downtown area. 

Vegetative Roofs. As discussed in Section 5.4, the MAT observed three vegetative roofs. A decade 

ago, vegetative roofs were seldom installed in the United States. Although this type of roof system only captures a small percentage of the current inventory of roofs, over the past few years 

there has been great increase in interest, awareness, and installation of this type of system. Unfortunately, currently there are no consensus design guidelines or building code requirements 

pertaining to their wind performance. Although no wind-related problems related to these vegetative roofs were observed by the MAT, wind-blown tree limbs are capable of breaking glazing, 

and there is potential for scour of the soil media. Also, for those systems that employ trays, there 

may be potential for tray blow-off. The wind vulnerability of vegetative roofs needs to be better 

understood and dealt with via design guidelines and code criteria before large numbers of vegetative roofs are installed in hurricane-prone regions.

Figure 6-4. 

Aggregate-surfaced BURs on two mid-rise buildings on the periphery of Houston’s central business district. The 

roof membrane blew off the penthouse roof, shown by the blue arrow (Figure 5-19 inset shows building locations).

HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 7-1

REcOMMENdATIONS 7

Recommendations

The recommendations in this report are based on the observations 

and conclusions of the MAT.

These recommendations are intended to assist the States of Texas and Louisiana, communities, 

businesses, and individuals in the reconstruction process, and to help reduce future damage 

and impacts from flood and wind events similar to Hurricane Ike. The recommendations will 

also help FEMA assess the adequacy of building codes and standards as they relate to flood hazard mapping and floodplain management requirements, and determine whether changes are 

needed or additional guidance is required. 

In addition to these recommendations, several of the recommendations in the MAT report on 

Hurricane Katrina (FEMA 549) are also applicable. Specifically, most of the public outreach 

recommendations apply equally to Hurricane Ike. 

7.1 Residential

The recommendations that follow are based on the MAT observations discussed in Sections 3.1 

and 3.2, and the conclusions presented in Section 6.1.

7Recommendations
7-2 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

7.1.1 Flood

Scour Around Foundations. Unexpected levels of foundation scour were observed between Surfside Beach, TX, and Holly Beach, LA. The local scour around building foundations greatly 

exceeded the vertical and lateral extents indicated by current design guidance. Damage from 

the scour was significant and widespread. Also, linear scour features that were likely associated 

with barrier island canals and roads were observed by the MAT. Numerous houses were undoubtedly affected by linear scour features, suffering either damage or destruction. 

Recommendation #1: FEMA should assist engineers and standards-writing organizations in developing new design and building code guidance that incorporates scour knowledge gained 

following Hurricane Ike.

Recommendation #2: Coastal land development guidance and practices should be revised to 

minimize potential linear scour (and associated building damage), and building design and 

construction practices should be modified to account for potential linear scour effects.

Recommendation #3: FEMA should study foundation scour in more detail during future poststorm investigations.

Building Elevation Relative to Flood Level. Much of the damage observed by the Ike MAT resulted 

from buildings not being adequately elevated to escape Ike’s storm surge, waves, and floodborne debris. Specific observations and conclusions, with related recommendations, follow.

BFEs shown on Effective FIRMs should not be used for reconstruction purposes in Ike-affected 

communities unless communities can demonstrate that Effective BFEs are adequate. Thousands 

of residential buildings were damaged or destroyed by Ike’s flooding, many of them constructed 

at or above the Effective BFEs. New flood studies are underway in Louisiana and Texas; preliminary flood maps have been produced in parts of Louisiana, but Texas preliminary maps are not 

expected before the end of 2009. 

Widespread damage outside the SFHA was observed; the Ike MAT recommends taking flood 

mitigation measures in the areas beyond the 

landward limit of the Effective SFHA, where 

there are likely to be no flood-resistant design 

and construction requirements (i.e., beyond 

Zone A and within Zones B, C, shaded X, or X), 

and in Zone A, which could experience Coastal 

A Zone or even Zone V conditions during a base 

flood. 

Recommendation #4: Until new DFIRMs are 

available and adopted, the MAT recommends 

requiring the following freeboard above the 

currently Effective BFEs for new construction, substantial improvements, and repair 

ADDING FREEBOARD TO NEW 

CONSTRUCTION

A comprehensive study of freeboard 

(American Institutes for Research, 2006) 

demonstrated that adding freeboard at the 

time of house construction is cost effective. 

Reduced flood damage yields a benefitcost ratio greater than 1 over a wide range 

of scenarios, and flood insurance premium reductions make adding freeboard 

even more beneficial to the homeowner. 

Reduced flood insurance premiums will 

pay for the cost of incorporating freeboard 

in a Zone V house in 1 to 3 years; in a Zone 

A house, the payback period is approximately 6 years. 

7 Recommendations
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 7-3

of substantial damage: freeboard specified by ASCE 24-05, plus 3 feet. Once new DFIRMs 

are available and adopted, the MAT recommends requiring new construction, substantial 

improvements, and repair of substantial damage to be elevated to or above the freeboard 

elevation specified by ASCE 24-05. 

Recommendation #5: Enforce Zone A design and construction standards in the area between 

the Effective SFHA landward limit and a ground elevation equal to the adjacent Zone A 

Effective BFE plus freeboard. This recommendation should be implemented before and following the adoption of new DFIRMs.

Recommendation #6: Enforce ASCE 24-05’s Coastal A Zone design and construction requirements in areas presently mapped as Zone A on the Effective FIRM. This recommendation 

should be implemented before the adoption of new DFIRMs; following adoption, Coastal A 

Zone requirements should be adopted in the area between the LiMWA and Zone V.

Recommendations #4, #5, and #6 are illustrated in Figure 7-1.

Figure 7-1. Comparison of Effective BFEs and flood hazard zones (upper figure), with MAT-recommended 

freeboard and flood hazard zones (lower figure) 

Recommendations 7
7-4 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS AND LOUISIANA

Based on damage observed to NFIP-compliant buildings throughout the area affected by Ike, 

minimum floor elevation requirements in NFIP regulations (44 CFR section 60.3) are inadequate and allow flood damage in Zone A, particularly by allowing the top of the lowest floor to 

be set at the BFE. 

Recommendation #7: FEMA should review its lowest floor elevation requirements for consistency with the requirements contained in the national consensus standard ASCE-24, Flood 

Resistant Design and Construction, and in light of the recommendations contained in the 

Evaluation of NFIP Building Standards (American Institutes for Research, 2006). Specifically, 

FEMA should consider requiring freeboard such that the entire floor system is at or above 

the BFE for all flood hazard zones. 

Even when buildings are elevated and constructed to meet minimum requirements, they are 

still vulnerable to flood damage when flood levels exceed the BFE. 

Recommendation #8: Property owners should be encouraged to design new and reconstructed buildings for flood levels above the BFE.

Some houses that were advertised as enhanced-code construction and intended to withstand 

greater-than-design level flood events sustained flood damage during Ike. Even though these 

buildings were elevated above the BFE, the MAT observed instances where scour and erosion 

exceeded the ability of the pile/column foundation to remain vertical, and instances where 

lateral loads and bending moments exceeded the material properties of the foundation piles/

columns—the piles/columns cracked or broke. 

Recommendation #9: Enhanced-code houses should be designed for erosion, scour, and flood 

loads associated with flood levels above the BFE, not just elevated above the BFE on otherwise minimally flood-compliant foundations. Entities certifying enhanced-code houses 

should review foundation calculations before granting enhanced-code status.

Flood damage to commercial buildings was, for the most part, similar to flood damage to residential buildings. 

Recommendation #10: The MAT recommends elevating commercial buildings to the same 

levels and on the same types of foundations as called for in residential recommendations 

#4, #5, and #6. See also Section 7.3, Future Studies and Standards Revisions, recommendation #33.

Parking Slabs. A wide range of parking slab performance was observed by the MAT: 

a) unreinforced, frangible parking slabs collapsed, as intended, with no apparent harm to elevated houses or their foundations; b) unintended failure of non-frangible parking slabs led 

to timber pile failures at elevated houses where broken slabs remained connected to foundation piles and transferred loads to the piles that the piles could not resist—racked foundations 

and broken piles resulted; and c) intact but undermined parking slabs sometimes contributed 

to foundation and building settlement, by increasing scour around the foundation (as water 

7 RECOMMENDATIONS
HURRICANE IKE IN TEXAS AND LOUISIANA MITIGATION ASSESSMENT TEAM REPORT 7-5

flowed between the bottom of the slab and the eroded ground) and by placing additional vertical load on the foundations. 

Recommendations #11: Coastal house foundations subject to scour and erosion should be 

designed to resist all loads imposed during coastal storm events, where possible, without 

benefit of parking slabs and grade beams to provide stiffness. Unreinforced, frangible parking slabs should be constructed under these houses when parking slabs are desired by the 

owner.

Recommendations #12: Where tall foundations cannot be constructed under coastal houses 

without added stiffness, grade beams with frangible slabs are preferred over structural slabs. 

This will minimize the weight that must be supported by an undermined foundation and 

minimize the potential of unintended load transfer from failed slabs to the foundation.

Siting. The widespread destruction and damage to houses situated closest to shorelines during 

Ike reinforced the principle that siting of buildings is critical to their survival during hurricanes. 

Siting of buildings close to eroding shorelines puts those buildings at risk and often results in 

erosion and flood damage to those buildings. 

Recommendation #13: The State and local governments of Texas and Louisiana should encourage siting away from eroding shorelines; employ coastal restoration, where justified, to 

mitigate erosion effects; and acquire erosion-damaged properties and prohibit reconstruction on those properties.

Breakaway Walls. One unintended consequence of elevating houses above the BFE has been 

taller and taller solid breakaway wall panels, which provide larger and larger floodborne debris 

elements when they break away. 

Recommendation #14: Lattice or louvers should be used instead of solid breakaway walls. Louver and lattice wall panels will remain intact longer than solid breakaway walls, resulting in 

less debris and less repair cost to homeowners. If solid breakaway walls are used, designers 

and owners should consider installation of flood vents in those walls. This may help to delay 

the failure of the walls, reduce floodborne debris, and reduce repair costs. 

Manufactured Homes. Destruction of manufactured housing occurred during Ike, either because 

the homes were not elevated to or above the BFE (this may have occurred through proper use of 

the 3-foot pier exemption permitted in existing manufactured home parks, or by misinterpretation of this exemption), or because homes had not been installed on flood- and wind-resistant 

foundations. 

Recommendation #15: All new and replacement manufactured homes should be elevated to 

or above the BFE using wind- and flood-resistant foundations such as those specified in 

NFPA 225-09. Manufactured home installations should follow the guidance contained in 

FEMA 85. Please note that the 1985 edition of FEMA 85 is currently under revision and is 

tentatively scheduled to be released later in 2009. 

RECOMMENDATIONS 7
7-6 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

7.1.2 Wind

In the areas observed by the MAT, Hurricane Ike was not a design wind event; wind speeds 

ranged from 90+ mph1

 from the west end of Galveston Island to 110 mph on Bolivar Peninsula, 

94 mph in downtown Houston, and 90 mph or less in other inland areas of Texas, 80 mph at the 

Texas-Louisiana border, to less than 50 mph east of Vermilion Parish, LA.

Structural. Though major wind damage to building structures was seldom observed by the MAT, 

wind damage to roof overhangs and sheathing was seen. This type of damage, though not pervasive, was seen from Galveston County to the affected Louisiana Parishes, including some 

enhanced-code construction homes.

Recommendation #16: Roof overhangs of widths up to 2 feet are routinely designed using prescriptive standards. Roof overhangs in excess of 2 feet should be designed to withstand wind 

pressures calculated using ASCE 7-05 guidelines.

Asphalt Shingles. The MAT observed a substantial amount of wind-damaged asphalt shingles. To 

achieve good wind performance, shingles with sufficient wind resistance should be installed. 

TDI currently allows 110-mph-rated asphalt shingles (i.e., Class F) for all wind zones in the Designated Catastrophe Area. Products are currently manufactured to meet ASTM D 7158, which 

provides for testing and classification of asphalt shingles to meet 120-mph (Class G) and 130-

mph (Class H) wind resistance.

Recommendation #17: When asphalt shingles are used, it is recommended that TDI require 

the use of shingles complying with ASTM D 7158 Class G shingles in Inland (I) and Inland 

(II) and Class H shingles in the Seaward Zone. 

Non-Load Bearing Walls and Wall Coverings. An extensive amount of envelope wall covering, primarily vinyl siding and fiber cement siding, was damaged by Hurricane Ike. 

Recommendation #18: Municipalities with building code authorities, along with TDI and their 

inspection program, should require that the installed products are on the approved and 

tested list and are installed in accordance to industry and manufacturer’s recommendations 

for high wind zone installations.

Doors, Windows, and Shutters. Few impact-resistant glazed window units were observed by the 

MAT in either Texas or Louisiana, with homeowners and builders opting to use shutters to provide debris impact protection of building openings. TDI currently requires only homes located 

in the Seaward Zone and the Inland (I) to be protected by impact-resistant glazing or shutters.

7 Recommendations

1 All estimated speeds in this chapter are peak gust, Exposure C at 33 feet taken from Estimates of Maximum Wind Speed 

Produced by Hurricane Ike in Texas and Louisiana (ARA, 2008).
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 7-7

Recommendation #19: It is recommended that opening protection by TDI include Inland (II 

[110 mph]) within 1 mile of the coastal mean high water line where the basic wind speed 

is equal to or greater than 110 mph, which is consistent with ASCE 7-05 and IRC 2003 

recommendations.

Roof Soffits, Fascias, and Gable Vents. Vinyl soffits and roof ridge ventilation systems frequently 

failed, thereby allowing water infiltration into the homes, causing damage. 

Recommendation #20: The TDI and Building Inspection Program should ensure that vinyl soffits are installed in accordance to industry and manufacturers’ recommendations for high 

wind zone installations. Ridge ventilation systems frequently allow wind-driven rain to enter 

the attic space and should not be allowed in Designated Catastrophe Areas.

Exterior-Mounted Equipment. All observed HVAC units mounted on the outside of the homes were 

elevated, per the guidelines in FEMA 55.

Recommendation #21: It is recommended that where railings are installed around elevated 

units, the railings either be removable or adequate space be provided on the platform to allow servicing of the units.

7.2 Critical Facilities

Critical facilities apparently continue to be 

designed and constructed without sufficient consideration of the guidance documents written to 

make critical facilities more hazard resistant. 

Recommendation #22: Critical facilities should 

be designed in keeping with available guidance (FEMA 424, 543, and 577). Existing 

critical facilities should be audited using 

FEMA 424, 543, and 577 and retrofitted 

where appropriate.

Recommendation #23: Update FEMA 424, 543, 

and 577: See Section 7.3, Future Studies and 

Standards Revisions.

Mitigation Project Performance. Some critical facilities that had received Federal mitigation grant 

funds to address previous damage or known vulnerabilities were found to still be vulnerable, either to the hazard against which they had presumably been mitigated, or against other hazards. 

Recommendation #24: Additional controls should be put in place by FEMA to ensure mitigation projects for critical facilities are properly designed and constructed/implemented.

FEMA GUIDANCE

FOR CRITICAL FACILITIES

FEMA 424, Design Guide for Improving 

School Safety in Earthquakes, Floods, 

and High Winds

FEMA 543, Design Guide for Improving 

Critical Facility Safety from Flooding 

and High Winds: Providing Protection to 

People and Buildings 

FEMA 577, Design Guide for Improving 

Hospital Safety in Earthquakes, Floods, 

and High Winds: Providing Protection to 

People and Buildings

Recommendations 7
7-8 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

7.2.1 Flood

Many of the critical facilities observed by the MAT were insufficiently elevated and vulnerable to 

flood damage. This was the case for most of the older buildings housing critical operations, but 

was also an issue for many recently constructed critical facilities.

Building Elevation Relative to Flood Level. New and replacement critical facilities continue to be located within the SFHA, and without freeboard. 

Recommendation #25: New and replacement critical facilities should be sited outside the 500-

year floodplain, where possible; where not possible, the critical facilities should be elevated 

higher than the residential and commercial building elevations called for in Recommendations #4, #5, #6, and #10. At a minimum, critical facilities should be elevated above the 

500-year flood level or the freeboard requirements of ASCE 24-05, whichever offers more 

protection to the facility. 

Equipment and Utilities. The MAT continues to see critical facility equipment and utilities damaged by flooding as a result of insufficient elevation. 

Recommendation #26: Do not locate equipment and utilities in basements or ground levels of 

critical facilities. Locate these above the BFE-plus-freeboard elevation. If elevation of these 

components is not feasible for existing critical facilities in Zone A, evaluate dry-floodproofing of these areas to an elevation several feet above the BFE. If the building structure cannot 

accommodate flood loads associated with dry floodproofing to this elevation, consider relocating the critical facility or replacing with a new critical facility.

7.2.2 Wind

Most of the critical facilities observed by the MAT had wind vulnerabilities, some of which were 

quite significant. Vulnerable elements primarily pertained to building envelopes and emergency 

power, but for some facilities, the MWFRS were also susceptible to wind damage. The presence of 

large numbers of wind-vulnerable facilities has also been observed by MATs in other locations of 

the United States and its Territories. To avoid wind, windborne debris, and water infiltration damage that results in partial interruption of facility operations or entire evacuation of a facility after 

passage of a hurricane, the following are recommended:

Recommendation #27: For existing facilities, perform a comprehensive vulnerability assessment of the MWFRS and building envelope. As part of the evaluation process, prioritize the 

identified vulnerabilities. FEMA 543 and 577 recommend such an evaluation regardless of 

building age for critical facilities located in hurricane-prone regions. 

The evaluation should also include assessing a facility’s capability of coping with loss of 

municipal utilities (i.e., electrical power, water, sewer, and communications). FEMA 543 and 

577 provide guidance on back-up systems and operations when loss of municipal utilities 

occurs, as well as guidance for performing remedial work on existing facilities.

7 Recommendations
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 7-9

If budget constraints prohibit timely evaluation of all critical facilities in a community, then 

the order of facility evaluation should be prioritized, commensurate with community needs 

and perceived vulnerability of the facilities. For example, EOCs, hospitals, and hurricane 

evacuation safe rooms are common high-priority facilities. These types of facilities would 

therefore normally be the type of facilities that would first be evaluated. However, if the local 

hospital was quite new and the community’s fire or police stations were quite old, evaluation 

of the fire or police station would likely be of higher priority. 

Upon completion of the evaluations of a community’s facilities, the order in which remedial 

work will be scheduled should be prioritized.

Recommendation #28: The MAT recommends that design and construction of new critical facilities follow the guidance in FEMA 543 and 577 so that wind vulnerabilities are not built into 

new facilities. This approach is more cost effective than building to minimum codes and standards and then retrofitting a building in the future to decrease its wind vulnerability. 

Emergency Equipment. The MAT observed critical facilities with significant wind vulnerabilities 

that were evacuated prior to hurricane landfall. However, in some instances (such as the fire station discussed in Section 4.3.4), equipment was not removed. 

Recommendation #29: The MAT recommends that emergency supplies and equipment (such 

as fire trucks) also be evacuated, to the extent possible. Otherwise, building failure can damage supplies and equipment, thereby making them unavailable for post-storm response and 

recovery. 

Mitigation Project Performance. As discussed in Sections 4.2.1, 4.3.2, 4.3.3, and 4.4.3, the MAT 

observed mitigation projects that were not sufficiently robust and/or were not sufficiently 

comprehensive. 

Recommendation #30: Before a critical facility receives a grant from the HMGP or Pre-Disaster 

Mitigation Grant Program, it is recommended that a comprehensive vulnerability assessment 

be conducted. All significant wind vulnerabilities (including those related to interruption 

of municipal utilities) should be mitigated by the grant work, and for those that are not, the 

remaining residual risk should be recognized and documented. 

Recommendation #31: It is recommended that the guidance in FEMA 577 be considered for 

healthcare facility mitigation projects, and that FEMA 543 be considered for all other critical facilities. Not all of the guidance is appropriate for all facilities, but if a recommendation 

is not implemented, that decision should be based on deliberation and consideration of residual risks.

Recommendation #32: It is recommended that a two-stage peer review be implemented for all 

projects. The first review should be made early in the design process to ensure that the scope 

and direction of the remedial work is fundamentally sound. The second review should be 

quite comprehensive, and should be conducted prior to bidding the construction work.

Recommendations 7
7-10 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

7.3 Further Studies and Standards Revisions

7.3.1 Flood

Observations by the Ike MAT revealed that additional studies, or implementation of existing 

study recommendations, will be required to improve design, construction, and siting practices 

for coastal buildings in the area affected by Ike.

Recommendation #33: Determine the causes of and contributors to foundation scour observed by the MAT along the Gulf of Mexico shoreline between Surfside Beach, TX, and 

Holly Beach, LA. Incorporate any needed changes to foundation design and construction 

practice to minimize and counteract such scour.

Recommendation #34: Gulf Coast States have ongoing shoreline erosion studies and coastal 

restoration initiatives (e.g., to characterize shoreline erosion, and to restore the habitat and 

storm buffer properties of marshes). Monitor the progress and review the findings of these 

studies and initiatives. Incorporate findings into flood hazard mapping procedures and into 

building siting, design, and construction requirements. 

7.3.2 Wind

The Ike MAT expected to observe a high level of building and cladding performance, given that 

Ike’s wind speeds were less than design levels. Though the MAT did not observe complete structural failure produced by Ike’s winds, the poor performance of roofing materials and cladding 

systems are indicative of poor design, construction, and inspection practices.

Design, Construction, and Inspection for Disaster Resistance. Construction of buildings to meet the 

minimum disaster-resistance provisions of model building codes is necessary for sustainability 

of communities. Contractor knowledge of acceptable building practices, plan review and independent inspections are necessary to ensure disaster resistance. It is not clear that the current 

administrative processes for controlling building in unincorporated areas of Texas provide the 

same level of disaster resistance as building approaches taken by other States. A warranty to the 

owner of the building that it will perform well in future disasters provides little value in a future 

distant disaster event because of the lapse of time, change in owners, and builders being out of 

business. 

Recommendation #35: The State of Texas should evaluate its current approach in unincorporated areas and determine if it provides an acceptable level of disaster resistance and 

building quality.

Roof Systems. Based on Hurricane Ike observations, the MAT makes the following recommendations regarding aggregate surface roofs, asphalt shingles, and vegetative roofs.

Aggregate Surface Roofs. The MAT observed glazing that was damaged by windborne roof aggregate (Figures 5-25 and 5-26). In urban areas where there are mid- and high-rise buildings, 

7 Recommendations
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 7-11

the presence of aggregate surface roofs has great 

potential to cause a significant amount of glazing 

damage. Beginning with the 2006 edition, IBC 

prohibits aggregate surface roofs in hurricaneprone regions, but there are no requirements 

for removing existing aggregate. Therefore, the 

following are recommended in urban areas in hurricane-prone regions:

Recommendation #36: Remove existing aggregate from built-up and sprayed polyurethane 

foam roofs to avoid damage to other buildings from wind-blown aggregate. 

Recommendation #37: For aggregate ballasted roofs, determine if the roof complies with the 

current edition of ANSI/SPRI RP-4 (available online at www.spri.org). If it does not, bring 

the roof into compliance with RP-4 or remove the aggregate.

Recommendation #38: It is recommended that criteria based on the two recommendations 

above be added to the ICC International Existing Building Code.

Asphalt Shingles. The MAT observed wind damage at several relatively new asphalt shingle roofs. 

However, because the labeling on the plastic strip on the underside of the shingles did not include wind resistance information, compliance with ASTM D 7158 could not be ascertained. 

Recommendation #39: Asphalt shingle product standard ASTM D 3462 should be revised to 

require labeling the underside of each shingle with its wind resistance classification (i.e., 

D, G, or H as determined in accordance with D 7158). Doing so will facilitate future storm 

damage research by providing investigators information on the wind resistance rating of installed products. 

Vegetative Roofs. The MAT observed three vegetative roof systems in downtown Houston. Although they were not damaged, nor did they cause damage to other buildings, they had the 

potential to do so. 

Recommendation #40: The MAT recommends that a consensus wind design guideline and 

wind-related building code requirements be developed for vegetative roof systems. The following interim guidance is recommended: In hurricane-prone regions, trees and shrubs 

should not be planted more than approximately 30 feet above grade. (The higher the elevation, the greater the wind speed, and hence the greater potential for limb blow-off and 

damage to glazing.)

Non-Load-Bearing Walls and Wall Coverings. Based on Hurricane Ike observations, the MAT makes 

the following recommendations regarding non-load-bearing walls and wall coverings.

Recommendation #41: The TDI inspection program should ensure that cladding products are 

manufacturer-rated for the appropriate wind zones, and that the methods of installation are 

consistent with the manufacturer’s recommendations. To improve the performance of the 

Aggregate removal will normally necessitate replacement of the roof system. 

Consult with a qualified design professional or professional roofing contractor. 

Recommendations 7
7-12 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS ANd LoUISIANA

cladding system, as well as the overall strength of the house, it is recommended that TDI 

consider requiring that the exterior wall substrates of residences be fully clad with plywood 

or OSB sheathing so that the sheathing is capable of withstanding design wind pressures 

that produce both in-plane and out-of-plane loads. A fully sheathed house is more robust 

and resistant to water infiltration in the event of the loss of wall cladding or windborne debris impacts.

Windows and Shutters. The MAT observed interior water damage due to window leakage (Figure 

7-2). The current minimum test pressures used to assess the resistance of windows to wind-driven rain are substantially below the design wind pressures. Hence, current minimum testing is 

inadequate to evaluate leakage potential during hurricanes. 

Recommendation #42: It is recommended that the window/curtain wall industry re-evaluate 

the test pressures that are currently used to assess resistance to wind-driven rain. 

Figure 7-2. 

Several windows at 

this house on Bolivar 

Peninsula leaked and 

wetted the carpet

The MAT observed a house under construction on Bolivar Peninsula (Figure 7-3) that had 

protected glazing in a breakaway wall. The breakaway walls and the window were destroyed by 

flooding. Currently, if a building is in a windborne debris region, ASCE 7, IBC, and IRC require 

protected glazing, including the glazing in breakaway walls. However, if the walls break away because of flooding, the windows will likely be destroyed as shown in the inset in Figure 7-3. 

Recommendation #43: Because glazing in breakaway walls is far more susceptible to flood 

damage than windborne debris, it is recommended that an exception be added to ASCE 7, 

IBC, and IRC that would allow the glazing in breakaway walls to be unprotected. Such an 

exception would reduce the cost of providing protected glazing, yet would not significantly 

increase the risk of damage.

7 REcOMMENdATIONS
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 7-13

7.3.3 Critical Facilities

Schools. The MAT observed schools in need of mitigation. FEMA 424 provides design guidance 

for new and existing schools, but the guidance is out of date. 

Recommendation #44: It is therefore recommended that the flood and wind chapters be updated to incorporate the applicable guidance in FEMA 543, as well as the new provisions 

presented in Recommendation #45 below.

Critical Facility Guidance. The MAT observed various types of critical facilities in need of mitigation. FEMA 543 and FEMA 577 provide guidance for new and existing facilities. 

Recommendation #45: Based on Hurricane Ike observations, it is recommended that the wind 

chapters in these two guidance documents be updated to incorporate the following conceptual guidance:

Roof Drainage. Roof drains and scuppers have the potential to be blocked by leaves, tree 

limbs and other windborne debris during a hurricane. If primary and overflow drains/scuppers become blocked, development of deep ponding water may inundate base flashings and 

Figure 7-3. 

The breakaway walls at 

this house were destroyed. 

The inset shows a window 

with laminated glazing 

that was washed away 

with the walls. Using 

protected glazing on the 

upper-level windows is 

logical, but protected 

glazing is of little value in 

breakaway walls.

REcOMMENdATIONS 7
7-14 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

cause leakage problems or lead to roof collapse. To avoid problems with blocked drains and 

scuppers, the following are recommended:

n Scuppers – Only a relatively small scupper is needed to drain a large roof area, provided 

the scupper opening is not blocked by debris. However, since small openings are more 

easily blocked than larger openings, it is recommended that scupper openings be 

much larger than normal. It is recommended that scupper openings be a minimum of 

24 inches wide and 16 inches high. In addition, it is recommended that the distance 

between scuppers be such that, in the event a scupper becomes blocked, the adjacent 

scuppers have sufficient capacity to drain the roof. 

n Roof drains – Avoiding blockage of drains is more problematic than avoiding blockage 

of scuppers. Drain lines need to be protected by domes to prevent debris from flowing 

into the lines and blocking them. For domes to be effective in protecting drain lines 

from blockage, the dome openings must be relatively small. To provide overflow 

protection, it is recommended that overflow scuppers be provided. Where drainage 

patterns necessitate that overflow protection be provided by overflow drains (rather 

than, or in addition to, overflow scuppers), it is recommended that additional overflow 

drains be installed. By doing so, if both a main drain and its nearby overflow drain 

become blocked, the additional overflow drain in the vicinity can provide drainage and 

avoid roof collapse.

n Maintenance – As part of pre-storm preparations, drains, scuppers, and gutters should 

be cleaned of debris in order to maximize their effectiveness in draining the roof and 

minimize the potential for their blockage during a hurricane. 

Flexible Connectors. Flexible connectors between rooftop ductwork and fans may leak (as 

discussed in Section 4.2.3) if they are in a deteriorated condition prior to a storm or if they 

are punctured by windborne debris. FEMA 543 and 577 recommend placing mechanical 

equipment in a penthouse to avoid these types of problems. However, if equipment is exposed, the following are recommended:

n Because of their small size, the potential for a flexible connector to be punctured 

by windborne debris is typically very low. However, if site-specific conditions present 

an unusually high potential for debris damage, it is recommended that the flexible 

connectors be protected by equipment screens or a custom-designed shield. 

n As part of annual roof inspections prior to hurricane season, it is recommended that 

all flexible connectors be inspected. Those found to be in a weathered condition (e.g., 

cracked, torn, or embrittled) should be immediately replaced.

Emergency Electrical Power. Hurricanes often cause widespread and prolonged interruptions of 

municipal power. Hence, because reliable power is essential to operating most critical facilities, they need emergency generators. Current codes and standards do not require emergency 

generators for all critical facilities and functions, nor are the requirements sufficient to ensure 

reliable power during prolonged power outages. In the aftermath of Hurricane Ike (as well as 

previous hurricanes), some critical facilities (including hospitals) had to be evacuated because 

7 Recommendations
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 7-15

of lack of power. It is for this reason that FEMA 543 and 577 provide a number of recommendations pertaining to generators. 

Recommendation #46: Based on the Ike MAT’s observations, FEMA 543 and 577 should be 

updated as follows:

n Currently, the guidance on electrical power does not differentiate between those critical 

facilities where power for some services cannot be interrupted (such as hospitals and 

EOCs) versus those where loss of power for several days is tolerable (for instance, a 

community center that serves to house emergency workers brought in after a storm). 

The current guidance to provide standby generator(s) in addition to the emergency 

generator(s), as well as devices to allow quick connection of portable generators, is overly 

conservative for facilities where loss of power for several days is tolerable. The current 

guidance to house generators in wind- and windborne debris-resistant enclosures is also 

overly conservative for facilities that can tolerate loss of power. The guidance should be 

differentiated based on the ramifications of loss of power to facility operations.

n The MAT observed several critical facilities that had generators fired by natural gas. 

One community had great success with this fuel source. Use of natural gas alleviates 

various potential problems associated with on-site storage of diesel fuel (such as adequate 

quantity of fuel for prolonged outages). However, at a facility observed by the MAT 

(discussed in Section 4.4.1), the natural gas supply was shut down by the gas supplier 

leaving the facility without power. Neither FEMA 543 nor 577 discuss natural gas-fired 

generators. It is recommended that this fuel type be added to the discussion, along with 

guidance regarding potential interruption of gas service (such as providing a diesel fuel 

back-up generator). 

n Guidance should be developed to determine what loads need to be supplied with 

emergency or standby power to enable facilities to provide services needed for 

operations during and/or after a hurricane.

SELF-AUDIT

A self-audit of a critical facility can help identify equipment that is essential to facility operations, but 

vulnerable to disruption by a natural hazard. The emergency plan should be reviewed periodically and 

revised as necessary.

When completing this audit for electrical power, the building owner should: 

1. Determine possible restoration times for municipal power during a natural disaster (restoration times 

will be significantly longer than those caused by more common causes of power disruption)

2.Determine emergency power and fuel source based on restoration time

3.Determine how electrical equipment that is vulnerable to flood, wind, or windborne debris damage 

should be modified or relocated

4.Determine what other equipment (not currently on emergency circuits) might be needed when restoration times are longer

5.Consider how portable emergency generators and switchgear will be connected if/when required 

Recommendations 7
7-16 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

Supplemental Emergency Power Recommendations. Many generators that are used for meeting the 

power demands from outages are intended to provide power for a relatively short duration. 

These standby generators are typically designed to supply power for a minimum of a few hours 

to a maximum of several days, not durations of a few weeks that often follow a hurricane. Standby generators often lack redundant control systems, redundant ancillary systems like fuel filters, 

adequate on-site fuel storage, and redundant capacity in their cooling systems. These limitations 

don’t significantly affect generator reliability if generators are run for short periods of time, but 

can greatly affect reliability if the generators are required to operate for several weeks. 

Prime-power generators, on the other hand, are designed to operate indefinitely. Their nameplate ratings are typically 15 to 20 percent lower than standby units (e.g., a 1,000 KVA standby 

generator will have a prime-source capacity of around 800 KVA). With prime-source units, more 

attention is given to maintenance under load and typically at least two units are specified to allow periodic shut-downs for maintenance. This additional capacity helps alleviate overheating 

and improves reliability. Redundant ancillary systems (like fuel pumps and filters) allow some 

components of the on-site power systems to be serviced while the system is operating; this type 

of maintenance can greatly increase system reliability. FEMA 543 and 577 recommend the use 

of prime-power generators.

Power Quality. The quality of electrical power provided by on-site generation can also be a 

concern. While this is generally not a problem with larger fixed generators, power quality can 

be problematic for smaller generators (particularly smaller generators operated near their capacity) and for portable units. Voltage control and frequency control are particularly critical. 

Sizing and Vulnerability. To be effective, all emergency power systems must be properly sized 

and be less vulnerable than the utility power system. Generators, transfer switches, fuel supplies, and control equipment should be protected from wind, windborne debris, and flooding, 

as recommended in FEMA 543 and 577. Generator sizing should take into account all loads 

required for the critical facility to function. While not required from a life-safety standpoint, 

mechanical equipment for temperature and humidity control should be considered critical 

equipment. In many hurricane-prone regions, temperature and humidity levels can increase 

rapidly to the point that they severely limit or prevent the delivery of critical functions. In 

new or renovated facilities, energy efficient equipment, such as high efficiency lighting, can 

be specified to reduce loads on emergency power sources. Alternative power sources, such as 

wind turbines or photovoltaic cells, should not be relied upon unless they are designed to resist high winds, windborne debris, and flooding. 

Temporary Generators. Temporary generators may be appropriate options for supplying power during prolonged power outages for those facilities that can tolerate loss of power until 

the temporary generator becomes operational. Temporary generators have the benefit of not 

requiring the capital expense of on-site emergency generators. If temporary generators are selected to provide power, the following issues should be considered:

n Availability of generators – Arrangements must be made before the event to ensure 

adequately sized generators are available when needed.

7 Recommendations
HURRICANE IKE IN TEXAS AND LOUISIANA MITIGATION ASSESSMENT TEAM REPORT 7-17

n Off-loading requirements – When generators are not trailer mounted, provisions must be 

available to off-load the generators on site.

n Fuel availability – Large generators require great amounts of fuel. Facilities need to ensure 

that adequate amounts of fuel are available.

n Connection to the facility – Methods to connect temporary generators to the facility should 

be installed before the event. Quick disconnects with manual transfer switches (often 

referred to as cam locks) should be installed. The connection point should be close to the 

generator location to reduce voltage drop that can result from long cables.

n Capacity and quality of power – The generators must be large enough to serve the 

requirement loads (i.e., they must be large enough to start the largest motor when 

operating all other loads) and the quality of the power must be sufficient to prevent 

damaging facility equipment.

Operation and Maintenance Staff. Temporary generators require maintenance and periodic 

testing and monitoring. Knowledgeable staff must be available to provide those services.

7.4 Building Codes

In Sections 7.2 and 7.3, the MAT has made specific recommendations on design, construction, 

and inspection to improve the disaster resistance of buildings. Some of the recommendations 

contained in this report are incorporated by reference into recent editions of the International Building Code and International Residential Code. It is recommended that state and local 

officials adopt and enforce a recent edition of a model building code -- keeping intact the minimum criteria established by the parent or expert document such as ASCE-7 or ASCE-24. It is 

also recommended that the MAT’s enhanced code recommendations be reviewed carefully. 

States and communities should consider adopting some of these recommendations, and designers, builders, and owners should consider voluntary implementation in cases where they are not 

adopted by government authorities.

RECOMMENDATIONS 7

HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT 8-1

PLANNING FOR A SUSTAINABLE COAST 8

Planning for a Sustainable 

Coast

The Galveston Bay region has been struck repeatedly by hurricanes 

in the past and will be again in the future. Reconstruction efforts 

and future development that consider and address the risks will 

result in communities that have fewer impacts and recover more 

quickly from future hurricanes. Rehabilitation and reconstruction 

should incorporate regional strategies that meet the needs of the area’s 

residents and businesses. Chapter 8 addresses general planning 

approaches.

One of the most critical aspects of establishing sustainable building practices is effective community and regional planning that takes into account the existing geological hazards and the 

importance of protecting the natural environment. This chapter presents some of the issues 

that coastal communities face. 

8Planning for a Sustainable 

Coast

Janice Olshesky
8-2 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

8 PLANNING FOR A SUSTAINABLE COAST

Hurricane Ike caused severe damage, leveled 

many homes, and destroyed a significant amount 

of infrastructure. In areas where the majority of 

the buildings were leveled, communities are offered an opportunity to rethink their coastal 

planning strategies. Rebuilding exactly as before 

will result in similar or worse damage in future 

hurricanes. Rather than attempting to rebuild 

what was there, the residents of these areas have 

an opportunity to thoroughly evaluate the coastal areas, and develop a responsible approach for 

their reuse. Taking a holistic view of the land and 

the environmental conditions that affect it will 

increase the probability of achieving a more sustainable result.

Models for community planning and housing design have changed over the last 50 years. For 

example, 50 years ago wetlands and marsh areas were not considered important. Over the past 

40 years, there has been a growing appreciation of the pivotal environmental role wetlands and 

marshes play in helping to buffer storms from damaging the built environment. Community planning and building design paradigms are shifting based on current research and studies, and it 

is vital to disseminate this knowledge to communities to help them plan for a more sustainable 

future. 

The first step in any effective urban planning or land-use planning is to perform a comprehensive evaluation of the site, including a complete understanding of the natural conditions and the 

forces acting on the site by the surrounding environment. The Gulf Coast ecosystem is dynamic, 

constantly changing due to the continuous and relentless ocean forces, and subject to drastic 

modifications during the occasional violent storm. The information that follows is intended to 

provide some guidelines and a description of some of the issues that coastal communities face.

8.1 Geologic Hazards and Coastal Communities 

8.1.1 Geologic Hazards That Threaten Coastal Communities

Southwestern Louisiana and southeastern Texas are in the Chenier Plain, which is the western 

extension of the Mississippi Delta. The physical characteristics and geologic framework of the 

Chenier Plain, mainland beaches, barrier islands, and tidal inlets partly determine the trends 

and rates of shoreline movement and related coastal changes for the region (Morton et al., 

2004). There are four external factors that exacerbate the already difficult environment. These 

include: 1) ground subsidence due to oil and gas withdrawal, groundwater pumping, and consolidation of subsurface soils; 2) rising relative sea levels (almost 1 foot, 8 inches [0.5 meter] in the 

past century); 3) increasing shoreline erosion resulting from human intervention in the natural 

system; and 4) destruction of the protective coastal dunes, saltwater marshes, and wetlands. 

“Before crossing the northern Gulf Coast, 

the counter-clockwise circulation of hurricane wind drives nearshore currents and 

large volumes of beach and shoreface sand 

alongshore. High tides, large waves, and 

strong currents that accompany the storms 

can leave semi-permanent marks on the 

barrier islands and beaches.” For example, 

Hurricane Allen (1980) reoccupied more 

than 60 washover channels through South 

Padre Island, TX, destroying the main road 

that runs the length of the island in several 

places (Morton et al., 2004).
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 8-3

PLANNING FOR A SUSTAINABLE COAST 8

8.1.1.1 Subsidence and Relative Sea-Level Rise

The effects of subsidence and rising sea levels are 

not easily differentiated. According to a USGS 

report, National Assessment of Shoreline Change: 

Historical Shoreline Changes and Associated Coastal 

Land Loss Along the US Gulf of Mexico (Morton et 

al., 2004), measurements on Galveston Island, 

TX, and Grand Isle, LA, show a relative rise in sea 

level of about 1 to 2 feet (0.3 to 0.6 meter) during 

the twentieth century, a rate approximately three 

times faster than the average global rise in sea level (0.6 foot [0.18 meter] per century). The relative rise in sea level is composed of both sea level 

rise and subsidence. Subsidence occurs as both a natural process and as a result of human activities. In southeast Texas, subsidence is attributed to natural processes, compaction of sediments, 

and historic withdrawal of groundwater. Most southeast Texas municipalities have now switched 

to surface water supplies (Ray Newby, personal communication). In Louisiana, subsidence is attributed to groundwater withdrawal and natural sediment compaction (Gabrysch, 1984). An 

additional manmade cause is that sediment supply to the Mississippi River delta plain has been 

artificially reduced by controlling the Mississippi River and preventing it from flowing into the 

Atchafalaya Basin. In addition, recent studies have suggested that hydrocarbon production has 

been partly responsible for accelerated subsidence and wetland loss (Morton et al., 2004). 

Figure 8-1 illustrates the steady rise in sea level at various locations along the Gulf of Mexico. 

Grand Isle, LA, experienced the steepest increase, with sea level rising about 1 to 2 feet during 

the twentieth century. Galveston has also experienced one of the steepest increases, with sea 

level rising about 1 to 2 feet (0.26 foot/year [6.5 mm/year]) during the twentieth century. 

Relative Sea Level

“At any coastal site the relative sea level 

includes the global sea-level component 

(eustasy), tectonic uplift or down warping, 

and at some locations subsidence that is 

the result of natural sediment compaction 

or subsidence induced by the withdrawal of 

subsurface fluids such as groundwater, oil, 

and natural gas.” (Morton et al., 2004)

Figure 8-1. 

Long-term trends in 

average annual sea level at 

selected tide gauges in the 

Gulf of Mexico 

Source: Morton et al., 

2004
8-4 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

8 PLANNING FOR A SUSTAINABLE COAST

Topographic lines shown on USGS Circular 1182 indicate that Galveston has experienced 

approximately 1 foot of subsidence over the past 100 years (Galloway et al., 1999). Bolivar 

Peninsula has likely experienced similar subsidence, as it is on the southeastern edge of the 

Houston area subsidence bowl (Ray Newby, personal communication). Texas City has experienced 4 feet of subsidence. The east side of Houston, in the Baytown area, has experienced 

up to 10 feet of subsidence. A recent study conducted by the Harte Research Institute for Gulf 

of Mexico Studies identifies a 2-foot, 2-inch relative sea level rise at Pier 21 on Galveston over 

the past 100 years (Yoskowitz and Gibeaut, 2009). The authors attribute 8.5 inches (0.216 meter) of the relative sea level rise to global sea level rise and 1 foot, 5 inches (0.436 meter) to 

local subsidence (Figure 8-2).

Figure 8-2. 

Relative sea level rise at 

Pier 21, Galveston, TX

Source: Yoskowitz and 

Gibeaut, 2009

The average global rate of sea level rise for the past century has been 0.6 foot (Morton et al., 

2004). NOAA/National Ocean Service’s (NOS) Center for Operational Oceanographic Products and Services (CO-OPS) collects and distributes observations and predictions of water levels 

and currents to ensure safe, efficient, and environmentally sound maritime commerce. Table 

8-1 presents increases in sea level predicted for the next 100 years based on available data from 

1957 to 2006.
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 8-5

PLANNING FOR A SUSTAINABLE COAST 8

Table 8-1. Predicted Sea Level Increases

Location NOAA Station # Trend based on monthly 

mean sea level data

Based on 

Data range

Change in 

100 years

Galveston Pleasure 

Pier, TX – Gulf side of 

Galveston Island

8771510

1/4 inch (6.84 mm) per 

year with a 95 percent 

confidence interval of +/- 

0.81 mm/year 

1957 to 2006 2.24 feet

Galveston Pier 21, TX – 

Bay side (west) of 

Galveston Island

8771450

1/4 inch (6.39 mm) per 

year with a 95 percent 

confidence interval of +/- 

0.28 mm/year 

1908 to 2006 2.10 feet

Freeport, TX – west of 

Surfside Beach 8772440

5/16 inch (4.35 mm) per 

year with a 95 percent 

confidence interval of +/- 

1.12 mm/year 

1954 to 2006 1.43 feet

Grand Isle, LA 8761724

11/32- inch (9.24 mm) per 

year with a 95 percent 

confidence interval of +/- 

0.59 mm/year

1947 to 2006 3.03 feet

Eugene Island, LA 8764311

3/8 inch (9.65 mm) per 

year with a 95 percent 

confidence interval of +/- 

1.24 mm per year

1939 to 2006 3.17 feet

Average global sea 

level rise

Various. NOAA 

samples 

throughout the 

world, from 

Iceland to 

Japan

1/16 inch (1.8 mm) per 

year

Various. 

Oldest is 1832 

(Sheerness, 

UK); most recent 

are typically 

2006

0.6 foot

Source: NOAA Tides and Currents, http://tidesandcurrents.noaa.gov/sltrends/msltrendstablefc.htm

Grand Isle and Eugene Island, LA, are the highest and Galveston is the second highest of all the 

U.S. Coastal Stations NOAA is taking readings from. The average global sea level rise is only 0.6 

foot. NOAA cites the Intergovernmental Panel on Climate Change (IPCC) Report, which estimates that the global sea level rise was approximately 1.7–1.8 millimeters per year over the past 

century (IPCC, 2008) based on tide station measurements around the world. 

Sea-level rise needs to be considered when planning new houses, businesses, critical facilities, 

new communities, and during future renovation along the southeast coast of Texas and southwest coast of Louisiana. This is especially true for these areas, as they are experiencing significant 

sea-level rise compared with other coastal areas monitored by NOAA stations throughout the 

United States. 
8-6 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

8 PLANNING FOR A SUSTAINABLE COAST

8.1.1.2 Shoreline Erosion

The upper Gulf Coast of Texas, which includes Galveston Bay and Bolivar Peninsula, is experiencing significant erosion, submergence, and wetland loss (Morton et al., 2004). Erosion of the 

Gulf shoreline at Bolivar Peninsula and Galveston Island has threatened numerous buildings in 

several beachfront communities. Small beach fills have been implemented, and geotextile tubes 

have been placed by Galveston County and private entities on the public beach to protect residences (Figures 8-3 and 8-4). 

Figure 8-3. 

Broken geotextile tube at 

Beachside Drive, Galveston 

Island, TX

Figure 8-4. 

Broken geotextile tube at 

Beachside Drive, Galveston 

Island, TX
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 8-7

PLANNING FOR A SUSTAINABLE COAST 8

As of January 2009, surveys at selected locations indicated that Hurricane Ike eroded an estimated 50 to 150 feet of lateral shoreline on Galveston Island, from just west of the Galveston seawall 

to approximately 6 miles west, and 50 to 100 feet of lateral shoreline on Bolivar Peninsula. 

Additionally, surveys indicated that an estimated 5 to 10 feet of vertical loss due to shoreline erosion occurred on Galveston Island, west of the Galveston seawall (Dr. John Anderson and Ray 

Newby, personal communication). 

According to the USGS assessment report (Morton et al., 2004), long-term rates of shoreline 

retreat along the Texas Gulf Coast have been measured up to 48 feet per year. Erosion rates of 

Gulf beaches in Texas are highest between Sabine Pass and High Island and downdrift (southwest) of the Galveston Island seawall. The most stable or accreting beaches in this area are on 

southwestern Bolivar Peninsula. Although short-term erosion rates are experienced by only 48 

percent of the shoreline, the average short-term erosion rate of 8.5 feet per year is higher than 

the long-term rate, indicating accelerated erosion in some areas. 

In the past decades, installation of jetties and seawalls/groins have affected the shoreline on 

the barrier island (Figure 8-5). Sand accumulates on the south side of the south Bolivar Roads 

jetty on Galveston Island, and established foredunes are abundant in that area. West of the 10-

mile-long Galveston Island seawall and groin (constructed to protect the City of Galveston from 

storm events), the beaches are retreating, with rates of erosion at the west end of the seawall 

reaching 12 feet per year. 

Figure 8-5. 

West end of the seawall 

at Galveston, TX. The 

concrete ramp (right 

foreground) was the road 

leading to the beach in the 

mid-1960s. Since then, the 

beach has eroded more 

than 492 feet.

SOURCE: Morton et al., 

2004
8-8 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

8 PLANNING FOR A SUSTAINABLE COAST

8.1.1.3 Dunes and Wetland Loss 

Dunes are an important natural resource for 

Galveston County and Chambers County, helping 

to protect the Texas coast from storms and flooding by dissipating the wave action of hurricanes. 

The dunes are dynamic, in constant change, and 

part of a natural cycle that stores sand and ensures the health of the beaches. Sand for the 

Gulf Coast barrier islands and beaches comes 

from eroding mainland shores, the continental shelf, and rivers such as the Rio Grande and 

Brazos Rivers. Historically, the Mississippi River 

also deposited its load of fine-grained sediments 

to the littoral system, which flows southwest on 

Bolivar Peninsula and Galveston Island; due to 

human intervention, the Mississippi River now 

deposits its load of fine-grained sediments at the 

edge of the continental shelf in relatively deep 

water, where it is unavailable to build beaches 

and barriers (Morton et al., 2004). Furthermore, 

the Mississippi River Gulf Outlet, MRGO, designed and constructed to keep channels open and 

direct the sediment load out to the continental shelf, acted as a funnel to focus the surge directly at New Orleans. Human intervention has resulted in subsidence, erosion, and salt water 

intrusion into the estuaries and bayous of coastal Louisiana (Warrick and Grunwald, 2005). 

Estimates of historic heights of dunes on Galveston Island range from 9 feet North American 

Vertical Datum of 1988 (NAVD88, 6 feet above a 3-foot beach) to 13 feet NAVD88 (9 feet above 

a 4-foot beach) on Galveston Island and Bolivar Peninsula (Dr. James Gibeaut, personal communication) to 11 to 14 feet NAVD88 on Galveston Island based on fine-grain size (Dr. John B. 

Anderson, personal communication). Mean sea level at Galveston is 0.5 foot NAVD88, and the 

grade height along the beach is typically 3 to 4 feet NAVD88. 

Most of the dunes along Galveston Island and Bolivar Peninsula were less than 5 to 6 feet 

NAVD88 high or non-existent before Hurricane Ike. The majority of developed areas had little 

to no dune development. Where developed areas were situated further back from the shoreline, the dunes were approximately 6 to 8 feet NAVD88. On the eastern end of Galveston Island, 

which is benefiting from sand increase trapped by jetties, the dunes were approximately 7 to 10 

feet NVAD88 high and about 30 to 40 feet wide (Dr. James Gibeaut and Ray Newby, personal 

communication). The dunes along Galveston Island and Bolivar Peninsula have been repeatedly damaged during hurricanes and significantly altered from human intervention. Galveston 

Island and Bolivar Peninsula dunes could help to provide a natural defense for the area if the 

dunes are allowed to grow back to their former heights, thereby providing significant protection 

to the residences, commercial buildings, and petrochemical infrastructure in Galveston Bay. 

While they could still be overtopped by high-water hurricanes, dunes would help to protect the 

area by taking the impact of the waves (Dr. James Gibeaut, personal communication). 

CASE STUDY – 

MONMOUTH COUNTY, NJ

For many years, the natural dunes in 

Monmouth County, NJ, were removed or 

altered to accommodate development. This 

made oceanfront properties more susceptible to damage from waves during major 

storms. The smaller beaches affected tourism and removed wildlife habitat. Dune 

restoration projects are now being initiated along the Monmouth County shoreline. 

These manmade dunes are once again 

providing storm protection and habitat, 

increasing the width of beaches and increasing tourism opportunities. (Source: 

Visit Monmouth County http://www.shore.

co.monmouth.nj.us)
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 8-9

PLANNING FOR A SUSTAINABLE COAST 8

Marshes, swamps, and wetlands play a vital role in 

the coastal zone. They have tremendous biologic, 

economic, flood, and coastal defense value. They 

perform beneficial chemical and physical functions, provide habitat for fish and wildlife, are a 

major economic resource, and play a critical role 

in flood mitigation. They help reduce erosion by 

absorbing and dissipating kinetic wave energy, increasing sediment deposition, and reducing the 

flooding hazards of hurricanes and other coastal 

storms by helping to protect coastal and inland 

properties from erosion and flooding.1

America’s Wetland Resources Center estimates that for every 3 miles of healthy coastal marsh 

that a hurricane crosses, 1 foot of storm surge is dissipated.2

 Tidal marshes act like a sponge to 

sop up water that pours in from the sea during a storm. Without marshes to absorb excess water, 

many low-lying areas would be prone to flooding. The Texas bay areas include wetlands that are 

1 to 2 miles wide. While these wetlands are not the scale of the wetlands of Louisiana, with 30+ 

mile wide stretches of marsh, they do still play a role in helping to dissipate storm surges along 

with their other biologic and economic value.

8.1.2 Discussion of Conflicts Between Coastal Communities and Geological Hazards

Over the last 100 years, our engineering ingenuity has enabled people to live directly on the 

beach. More people live along the coast and more people are moving to the coast than ever in 

our past. According to the U.S. census figures, half of the U.S. population lives in coastal areas 

comprising 17 percent of the contiguous land area (Crossett et al., 2004). According to the Texas General Land Office (GLO), more than 25 percent of the Texas population lives within the 

18 counties that comprise the coastal management zone. Houston is the fourth largest U.S. city, 

and the third largest metropolitan area close to a coast. In recent years, there has been a rapid 

rise in development along the upper Texas coast. In the face of increased development and 

increased interest in living on the coast, communities need to be more aware of the dynamic 

nature and dangers of the coast and the value of the natural barriers that protect it. 

The trends show that more people will be moving to the upper Texas coast. The trends also show 

an increase in relative sea level rise. In addition, the upper Texas coast has been experiencing 

coastal ecosystem erosion for some time. The most important value of the natural ecosystem, 

wetlands and dunes, is that they provide a buffer from hurricane damage, flood control, nursery 

grounds for fisheries, and water supply and treatment. It is vitally important to the health of the 

residences, businesses, and infrastructure that the community at large begin to recognize the 

value of the natural ecosystem and protect it to nurture it back to health. 

“Wetland losses, which constitute about 

75 percent of the total land losses, have 

dramatically accelerated both directly in 

response to human activities or indirectly 

as a result of modifications to the coastal 

system. Rates of land loss around bays 

are highest near the heads of the largest bays where long wave fetch and high 

bluff elevations produce unstable conditions” (Morton et al., 2004, pg. 31).

1 Coastal Texas 2020 Public Input and Scoping Document, Texas General Land Office http://wwwdb.glo.state.tx.us/res_mgmt/

ct2020/scopingdocument.cfm.

2 America’s Wetland Resources Center, The Basic Facts, http://www.americaswetlandresources.com/background_facts/basicfacts/

FAQs.html. 
8-10 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

8 PLANNING FOR A SUSTAINABLE COAST

As the dynamic islands change and erosion continues to remove land along the barrier islands, 

houses are ending up close to the water’s edge, or in the water. With development this close to 

the water, the dunes cannot rebuild. The upper Texas coast needs to consider critical areas for 

the health of the ecosystem and build sustainable communities for future building. As part of 

the reconstruction and recovery after Ike, some questions that coastal communities should consider include:

n How do we modify existing communities and redevelop damaged communities in light of 

the above information? 

n Is building higher and stronger the answer?

n How do we address the presence of residences built in critical areas of the ecosystem, in an 

area that might be considered a no-build zone?

n Should we create a buyout program for those critical areas? 

n How do we protect unhealthy coastal ecosystems from further development?

n How do we allow the dunes to restore themselves?

n Are additional regulations needed to enforce dune and coastal wetland protection?

n Are joint efforts with county, State, and Federal agencies needed?

When coastal wetlands are in private ownership, decisions are typically made on the basis of 

what is best for the owner, not society at large. It is important that the land owners recognize the 

value of the coastal ecosystem—this can be accomplished through education and public outreach programs (refer to recommendations). Landowners that make wise decisions regarding 

the coastal ecosystem should be publicly recognized.

8.2 Existing Planning Resources and Programs

8.2.1 Texas 

Land use planning is critical to Galveston Island barrier island and to the Bolivar Peninsula, 

and the risks and vulnerabilities of these areas need to be identified. Texas has existing programs and resources that can be used by municipalities to guide reconstruction and plan for 

the future. 

Coastal Erosion Program and Coastal Texas 2020 Report

The Texas State coastal erosion program was initiated in 1999 when the Coastal Erosion Planning and Response Act, CEPRA, was enacted. In 1996, the Texas GLO submitted the Texas 

Coastwide Erosion Response Plan3

 to the 75th Texas Legislature describing the problems caused 

by erosion of the Gulf beaches and bay shorelines and the need for funding projects to mitigate 

3 Texas Coastwide Erosion Response Plan, 2004 Update http://www.glo.state.tx.us/coastal/cerp/index.html
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 8-11

PLANNING FOR A SUSTAINABLE COAST 8

the damages. In 1999, the 76th Texas Legislature enacted the CEPRA supplying initial funding for 23 erosion response projects (Cycle 1 projects). The 77th Texas Legislature supported 

funding for another set of projects (Cycle 2 projects). In May 2004, the Texas Legislature supplied funding for half of the initial amount requested for the Cycle 3 projects. The Coastal 2020 

report was issued in 2005 and submitted to the 79th Texas Legislature and to the 109th Congressional Delegation. The purpose of the report is to encourage lawmakers, throughout Texas, to 

consider that coastal issues need to be addressed and require funding. 

Geohazards Map Program

Based on recommendations in a report titled “Living with Geohazards on Galveston Island: A 

Preliminary Report with Recommendations, Prepared for and submitted to the Galveston, Texas City 

Council, July 2, 2004,” (Gibeaut et al., 2004), the Coastal Research Group, Texas Bureau of Economic Geology (BEG) prepared a preliminary geohazards map in July 2004, and has prepared 

more recent versions showing current conditions for Galveston Island. The map shows lowlying areas and historical erosion rates and projects them into the future. The geohazard map 

presents a best-case scenario, as it uses only historical average global sea-level rise and subsidence rates, and does not reflect any increase of these rates based on new studies. The historical 

erosion rates presented in the Galveston Island geohazards map are based on 60 years of aerial photograph documentation that track shoreline migration. The earliest aerial photographs 

were taken around World War II. The elevation data is from LiDAR measurements taken by the 

BEG over the last 10 years. Maps such as the City of Galveston geohazard map can provide useful 

information for homeowners and businesses when selecting a site to locate a building.

8.2.2 Louisiana 

This section describes several coastal planning programs and resources in Louisiana.

Coast 2050: Toward a Sustainable Coastal Louisiana

In 1998, Governor Foster and his administration prepared a strategic plan, Coast 2050, to establish a blueprint for comprehensive coastal restoration in Louisiana. The preparation of Coast 

2050 was a joint planning initiative between the Louisiana Wetland Conservation and Restoration Authority (LWCRA), the Breaux Task Force, and the Louisiana Department of Natural 

Resources Coastal Zone Management Authority (LWCRA, 1998).

The development of the plan included:

n Soliciting public opinion and recommendations

n Resolving conflicts between restoration goals, coastal zone development, and infrastructure 

needs

n Formulating a plan that was acceptable to the public, scientifically sound, and achievable 
8-12 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

8 PLANNING FOR A SUSTAINABLE COAST

Coastal Wetlands Planning, Protection and Restoration Act

The Coastal Wetlands Planning, Protection and Restoration Act (CWPPRA), which was submitted by Senator John Breaux and authorized by Congress in 1990, provides for targeted funds to 

be used for planning and implementing projects that create, protect, restore, and enhance wetlands in coastal Louisiana. The CWPPRA, also known as the “Breaux Act,” provides Louisiana 

with approximately $40 million annually to assist in long-term conservation of Louisiana’s coastal wetlands. The Louisiana Coastal Wetlands Program established a Federal task force,4

 the 

CWPPRA Task Force, which consists of five Federal agencies and the State of Louisiana. USACE 

tracks the project status of all of the CWPPRA projects. It also constructs many of them.

Coalition to Restore Coastal Louisiana

The Coalition,5 formed in 1988, is a non-profit advocacy organization whose mission is the protection and restoration of a sustainable coastal Louisiana. The goal is to reverse the pattern of 

net land loss in coastal Louisiana and to reestablish a sustainable balance to its geologic processes and communities. In pursuit of this goal, the Coalition advocates the implementation of 

sound coastal policies and monitors coastal activities to ensure that stringent regulations and 

enforcement policies are maintained. 

8.2.3 Nationwide Initiatives

Smart Growth

Rebuilding damaged communities in the 

Galveston Bay, TX, area and southwest Louisiana, provides local and State governments an 

opportunity to promote Smart Growth principles. Smart Growth communities promote 

development in ways that preserve natural 

lands and critical environmental areas, protect 

water and air quality, and reuse already-developed land. Smart Growth communities 

conserve resources by reinvesting in existing 

infrastructure and reclaiming historic buildings. Smart Growth practices are very old; this 

is how older urban villages, towns, and cities 

such as the City of Galveston were shaped. 

Infrastructure, businesses, and residences are concentrated to take advantage of walkable 

neighborhoods. These denser neighborhoods provide a wealth of resources. The denser neighborhoods provide solutions to concerns facing many communities about the impacts of the 

highly dispersed development patterns of the last 50 years. The walkable neighborhoods provide an alternative to driving long distances to get to work or to a store each day, especially as 

4 http://crcl.org/stateandfederalplans/cwppra.html and http://www.lacoast.gov/cwppra/

5 http://crcl.org/aboutus.html

Smart Growth Network

The Smart Growth Network (SGN) is a partner coalition and consists of over 30 public 

sector, private sector, and nongovernmental 

organizations seeking to create smart growth 

in neighborhoods, communities, and regions 

across the United States. The SGN works to 

encourage development that serves the economy, community, and environment. Individual 

membership information, publications, and information about smart growth are available 

online at www.smartgrowth.org.
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 8-13

PLANNING FOR A SUSTAINABLE COAST 8

gas prices rise and while America is dependent on foreign oil. The denser neighborhoods are 

an alternative to abandoning a neglected urban site and developing instead prime farm land, 

thereby damaging our environment at the fringe of suburbia. Local and State policymakers, 

planners, architects, developers, and others are incorporating Smart Growth as a solution to 

these challenges (International City/County Management Association [ICMA], 2002). Good 

examples of Smart Growth principles in action on Galveston Island are the City of Galveston 

and the New Urbanism community, Beachtown (Figure 8-6). The City of Galveston is located 

behind the seawall. A future location for new construction or renovation could be behind the 

seawall in this walkable community. Beachtown, located at the east end of Galveston, is one of 

the few places on the island that is accreting, and new residences could take advantage of this. 

Figure 8-6. 

Beachtown, TX, under construction

A key element of Smart Growth principles is mixed land use. By mixing land use—such as residential, commercial, and institutional—the framework for a walkable community is in place. 

Another key element is to provide a mix of housing options, such as high-density residential to 

low-density residential. Higher density housing will support commercial and institutional uses. 

For example, a residential neighborhood that provides a 10-story mid-rise development, a threestory courtyard apartment complex, a townhouse development, and single-family houses will 

provide a mix of residential options. The denser residential buildings will sustain commercial 
8-14 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

8 PLANNING FOR A SUSTAINABLE COAST

and institutional activities, including commercial areas for groceries, pharmacies, hardware 

stores, restaurants; professional areas for doctors; and institutional buildings for recreational 

activities, community centers, and libraries. 

Open spaces can be preserved for uses such as 

parks, farmland, and critical environmental 

needs. A variety of transportation means can be 

provided, such as bike paths, sidewalks, buses, 

rail, and automobiles. 

Implementing Smart Growth is a change to 

the way of doing business. It is vital to include 

community collaboration in decisionmaking 

related to Smart Growth. Local governments, 

lenders, community groups, zoning officials, 

developers, transit agencies, State governments, and others need to work together to 

provide the necessary changes in the way building and planning are done (ICMA, 2002). For 

example, there are zoning laws in place that 

have not caught up with these new practices. 

These zoning laws would need to be modified 

to promote Smart Growth practices. A new development called Beachtown under construction along the eastern end of Galveston Island will 

be a walkable community along the beach with a town center (Figure 8-7). 

Figure 8-7. 

Beachtown, TX, under 

construction

Smart Growth Principles

1. Mix land uses

2. Take advantage of compact building 

design

3. Create a range of housing opportunities 

and choices

4. Create walkable neighborhoods

5. Foster distinctive, attractive communities 

with a strong sense of place

6. Preserve open space, farmland, natural 

beauty, and critical environmental areas

7. Strengthen and direct development toward existing communities

8. Provide a variety of transportation 

choices

9. Make development decisions predictable, 

fair, and cost effective

10. Encourage community and stakeholder 

collaboration in development decisions

For more information: 

Smart Growth Web site, 

www.smartgrowth.org

Getting to Smart Growth: 100 Policies for 

Implementation (ICMA, 2002)
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PLANNING FOR A SUSTAINABLE COAST 8

Historic Preservation

Historic buildings are protected under the NHPA and are a recognized value to our national 

culture. Historic buildings are part of the history and fabric of Galveston. Additionally, older 

homes can provide useful information related to sustainable building practices. Older homes 

were designed to minimize solar gain through the use of deep porches, and overhangs, and they 

functioned adequately with daylight as the primary source of illumination. They were designed 

with high ceilings and cross-ventilation, with raised first floors to cool the buildings. Many of 

these homes may have had their own cisterns for rainwater catchment. With proper attention to 

disaster-resistant details, these practices can all support passive survivability of the building.

Reuse of existing buildings as opposed to building a new structure is one of the most effective strategies for minimizing environmental impacts. Reuse results in less habitat disturbance 

and typically less infrastructure development. Rehabilitation of existing buildings results in less 

waste sent to landfills. However, effective reuse of existing buildings requires that they be retrofitted to reduce the possibility that they will be damaged and destroyed by future hurricane 

winds or storm surge.

8.3 Recommendations for Rebuilding After Ike

The following are recommendations for communities and municipalities to consider as they begin rebuilding after Ike and planning for the future. 

8.3.1 Specific to Local Communities

Sustainable Land Use Planning Recommendations

Coastal Counties:

Recommendation #1: Identify the risks to and vulnerabilities of the coastal communities and 

develop mitigation strategies to address them as part of the community’s master plan. Identify zoning, land ownership, resident populations, tourism, and economic activity, and identify 

where and how vulnerable these assets are to natural hazards. 

City of Galveston and Jamaica Beach: 

Recommendation #2: Prepare a Sustainable Land Use Plan that considers that more severe 

hurricane impacts can be expected in the future and incorporates the geohazards map prepared by BEG, and relative sea-level rise for the next 50 years as a minimum. 

Bolivar Peninsula:

Recommendation #3: Prepare a Sustainable Land Use Plan and that considers that more severe 

hurricane impacts can be expected in the future and incorporates a geohazards map and an 

additional overlay map that shows relative sea-level rise for the next 50 years as a minimum. 
8-16 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

8 PLANNING FOR A SUSTAINABLE COAST

City of Galveston, Jamaica Beach, and Bolivar Peninsula:

Recommendation #4: Provide an overlay map accounting for the natural dynamism of the barrier peninsula. A Sustainable Land Use Plan should be a living document that changes over 

time. A sustainable landscape is a prerequisite for both storm protection and environmental 

restoration. Prepare a map showing the amount of shoreline erosion that will occur over the 

next 50 years if current trends are maintained. 

Recommendation #5: Allow new construction and additions only in areas that are deemed 

safe with low risk, based on the Risks and Vulnerabilities and the Sustainable Land Use Plan, 

which includes future trends over the next 50 years. This will ensure that development stays 

out of the fragile coastal zone that needs to be protected for dune dynamism and growth. 

Recommendation #6: Municipalities require that future development projects comply fully 

with the Clean Water Act 404 requirements before granting construction permits.

Galveston Island, Bolivar Peninsula, Galveston Bay Region, and Southeast Louisiana:

Recommendation #7: Build a coalition of municipal, community, and business partners to discuss economic investments at stake. Encourage businesses to think about their response to 

natural hazards over the long term, both operationally and physically. Emphasize that building codes are intended to provide a minimal level of life-safety and building performance. In 

coastal areas, it is prudent to design and construct more conservatively. This includes commercial buildings, in order to increase their potential for being operational after a disaster. 

Recommendation #8: Using NOAA’s “Coastal Resiliency Index: A Community Self-Assessment, 

A Guide to Examining How Prepared Your Community is for a Disaster” (Emmer et al., Date 

Unavailable), prepare a Community Self-Assessment and obtain a Coastal Resiliency Index 

rating. This rating will aid community leaders in predicting if their community will reach 

and maintain an acceptable level of functioning and structure after a disaster. The goal 

of this Community Self-Assessment is for every community to become highly resilient; the 

guide reviews critical infrastructure. 

Recommendation #9: Modify land use maps to enable Smart Growth principles to encourage 

mixed land uses; institute policies to enable Smart Growth.

Protection of the Natural Environment

Local Municipalities 

Increase protection of dunes on Galveston Island and Bolivar Peninsula to allow the dunes to 

stabilize and achieve their natural, undisturbed heights (estimated to be approximately 9 to 14 

feet NAVD88). Examples of best practices include:

Recommendation #10: Conduct research into storm history and beach dynamics to determine 

how wide a buffer strip is necessary to maintain the dunes. These vary according to specific 

locations. Arbitrary dune widths are not useful and can easily be breached. 
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT 8-17

PLANNING FOR A SUSTAINABLE COAST 8

Recommendation #11: Prohibit any traffic, including foot and motorized/non-motorized 

vehicles. Walking on dunes jeopardizes their 

stability by damaging the fragile anchoring 

root system. While providing storm protection and habitat, dunes tend to reduce 

access to beaches. Provide boardwalks over 

the dunes to protect the vegetation. Pathways could also be designed between the 

dunes to limit their damage. Placing fences 

along the pathways will confine pedestrians 

to the paths.

Recommendation #12: Institute a dune revegetation program and put measures in place to 

allow dunes to achieve their former heights. 

High-elevation continuous dunes effectively block storm surges and prevent island 

overwash. Restoration, maintenance, and protection of dunes are vital to ensuring storm 

protection, beach stability, and increasing the 

economic health of the region. 

Recommendation #13: Institute community education programs to place signage and provide 

literature about the importance of dunes. 

Galveston and Chambers Counties

Recommendation #14: Encourage local municipalities to ensure that building permits are in 

compliance with Texas Wetlands Conservation Plan. The Texas Wetlands Conservation Plan6

provides a non-regulatory, incentive-based approach to wetlands management. 

Recommendation #15: Initiate a local or regional wetlands protection program. According to 

the USGS report (2004), not many dune or habitat restoration projects had been started. It 

is very important that these projects be initiated as soon as possible to begin to establish basic protection. Dunes often take many years to become stable. 

8.3.2 General Recommendations – State Level 

Recommendation #16: Update and revise accordingly the Coastal 2020 (20047) plan to include 

the devastation of Ike and recommendations in this Ike MAT report. Fully fund and expedite its implementation. 

Several publications are available on topics 

of dune planting and construction, including: Restoration of Sand Dunes along the 

Mid-Atlantic Coast (Hamer et al., 1992), 

Landscaping at the Seashore (Rutgers, 

1980), and Guidelines and Recommendations for Coastal Dune Restoration and 

Creation Projects (New Jersey Department 

of Environmental Protection, 1985).

6 http://www.tpwd.state.tx.us/landwater/water/habitats/wetland/publications/conservation_plan.phtml

7 http://www.glo.state.tx.us/coastal/ct2020/index.html

AMERICA’S ENERGY COAST

Residences and businesses located in 

the Chenier Plain—southeast Texas and 

southwest Louisiana—have many common 

interests as the alliance, America’s Energy 

Coast, has found out. America’s Energy 

Coast is a loose alliance of environmentalists, oil companies, government agencies, 

and shipping interests that is calling on 

the Nation to do two things that are often 

seen as mutually exclusive: invest in restoring a degraded ecosystem and, at the 

same time, protect and increase oil production. For more information, see: http://www.

americasenergycoast.org/files/120208AECActionFrameworkFINAL.pdf.
8-18 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

8 PLANNING FOR A SUSTAINABLE COAST

Recommendation #17: Initiate a regional coalition including coastal communities of southeast 

Texas and southwest Louisiana to address coastal planning and hazard mitigation. Consider 

supporting the alliance of America’s Energy Coast, which includes interests along the southeast Texas coastline (refer to text box). 

Recommendation #18: Institute policies to enable Smart Growth. 

8.3.3 General Recommendations – Federal Level

Recommendation #19: Federal agencies with technical expertise, such as NOAA, USACE, and 

others, should help communities identify the most effective protective measures to put in 

place for coastal wetlands to ensure wetland health. 
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT A-1

ACKNOWLEDGMENTS A

Acknowledgments

The Federal Emergency Management Agency would like to 

acknowledge the contributions of the following persons to the 

Mitigation Assessment Team study of the areas affected by 

Hurricane Ike:

AAcknowledgments

J.T. Agregard 

Operations Manager, Houston Transtar, Houston, TX

Dr. John Anderson

Professor of Geology and Geophysics, Rice University, Houston, TX 

Barry Bergeron

Bergeron’s Electric, Sulphur, LA 

Mike Blount 

Senior Project Manager, Crown Team Construction, Beaumont, TX

Dana Bres

U.S. Department of Housing and Urban Development, Washington, DC

Antoine Bryant

The Bryant Design Group, LLC, Houston, TX

Bill Coulbourne, PE

Director, Wind and Flood Hazard Mitigation, Applied Technology Council, Rehoboth Beach, DE

Lori Cummings 

Assistant City Manager, City of Port Neches, TX
A-2 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

A ACKNOWLEDGMENTS

Dr. Eileen Curl

Chairperson & Professor, Dishman Department of Nursing, Lamar University, Beaumont, TX

Windell Curole 

Executive Director, South Lafourche Parish Levee District, Galliano, LA

Chip Dence

East End Builders, Victoria, TX

Chad Deshotel

Majestic Homes, Lake Charles, LA

Dana Dugas

Affordable Homes, Inc., New Iberia, LA

Charles Everetts

Mayor, Village of Tiki Island, TX

Wayne Fender

Fender Homes, Lake Charles, LA

Capt. Bruce Francois

Grand Isle Police Department, Grand Isle, LA

David Franklin, PE

Aran & Franklin Engineering, Inc., La Marque, TX

Jennifer Gerbasi

Recovery Planner, Terrebonne Parish & City of Houma, LA

Ian Giammanco, PhD Candidate

Texas Tech Hurricane Research Team, Lubbock, TX 

Dr. James Gibeaut

Harte Research Institute for Gulf of Mexico Studies, Texas A&M University, Corpus Christi, TX

Bill Grim 

Supervisor, Operations & Maintenance, Chevron, Houston, TX

Leigh Guidry 

Executive Assistant, Greater Lafourche Port Commission, Galliano, LA

Gene Hafele 

Meteorologist-In-Charge, National Weather Service, Dickinson, TX

Karen Hagerman 

City Secretary, Village of Tiki Island, TX

Shalia Hampton 

Administrator, Winnie Community Hospital, Winnie, TX

Officer Mitch Hohensee

Greater Lafourche Port Commission Police, Galliano, LA
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT A-3

ACKNOWLEDGMENTS A

Darrell Hunter

Building Inspector, Village of Tiki Island, TX 

John Ingargiola

FEMA HQ, Washington, DC

John S. Jacob

Texas Sea Grant, College Station, TX

Mike Johnson

Mike Johnson Homes, Bridge City, TX

Jerry Jones 

City Manager, Bridge City, TX

Phil Kabza, FCSI, CCS, AIA

SpecGuy®, Charlotte, NC

Richard Keleher, AIA, CSI, LEED, AP 

Richard Keleher Architect, Concord, MA

Rob Kistler, AIA

The Facade Group, LLC, Portland, OR

Chris Koerner, PE, BCEE

Environmental Network International, LLC, Oakton, VA

Michael Lege

Crown Team Texas, Beaumont, TX

Paul J. Lemoine 

Chief of Police, Port Neches Police Department, Port Neches, TX

Nathan Letroise 

Property Manager, Galveston Courthouse, Galveston, TX

Philip Line

American Forest and Paper Association, Washington, DC

Bill Little 

Little Investments, Inc., Beaumont, TX

Jeff Mabrey 

Property Manager, Hines, JPMorgan Chase Tower, Houston, TX

Wesley S. Maida 

QRC Operations Manager, Flowserve Corporation, Port Arthur, TX

Mitch McDonald

Senior Planner, Terrebonne Parish & City of Houma, LA

Ray Newby, PG

Geomorphologist/Project Manager, Texas General Land Office, Coastal Resources Program, 

Austin, TX
A-4 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

A ACKNOWLEDGMENTS

Greg Ormsby

FEMA Contractor, Washington, DC

Judd Peterson, AIA 

President, Judd Allen Group, Edina, MN 

John Plisich

FEMA Region IV, Atlanta, GA

Dan Reilly 

Warning Coordination Meteorologist, National Weather Service, Dickinson, TX

Spencer Rogers

North Carolina Sea Grant, Raleigh, NC

Ron Rohrbacher 

Perry Homes, Houston, TX

Michael Scanlon, PE 

President, Norex Engineering Inc., Houston, TX

John Schroeder, PhD

Texas Tech Hurricane Research Team, Lubbock, TX 

Taylor J. Shelton 

Public Works Director, City of Port Neches, TX

Rodney Townsend

R & D Quality Construction Home Builders Inc., Bridge City, TX

Don Veronie

Heritage Builders, LLC, Sulphur, LA

Larry Voice

FEMA Disaster Assistance Employee

Jim Walker 

Construction Manager, Facilities Operations & Management, The University of Texas Medical 

Branch, Galveston, TX

Mark Williams

Mark Williams Home Builder, Beaumont, TX

Dewayne Willoughby 

Senior Chief Engineer, JPM Realty Group, Houston, TX

Maurice Wolcott

Louisiana Sea Grant, Baton Rouge, LA

Chandra Franklin Womack

Aran & Franklin Engineering, Inc., La Marque, TX
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REfERENcES ANd fEMA PublIcATION lIST B

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1, 2006.

Warrick, Joby, and Michael Grunwald, 2005. “Investigators Link Levee Failures to Design 

Flaws: Three Teams of Engineers Find Weakened Soil, Navigation Canal Contributed to La. 

Collapses,” The Washington Post, Monday, October 24, 2005; Page A01.

Yoskowitz, David, and James Gibeaut, 2009. “Impact of Relative Sea Level Rise on Galveston 

Bay,” PowerPoint presentation, Harte Research Instititue for Gulf of Mexico Studies, Texas 

A&M University, Corpus Christi. January, 2009.

FEMA Publications and Resources

FEMA post-disaster reports available through FEMA publications: 1-800-480-2520 and at 

http://www.fema.gov/rebuild/mat/mat_reprts.shtm.

FEMA 55 Coastal Construction Manual: Principles and Practices of Planning, Siting, 

Designing, Constructing, and Maintaining Residential Buildings in Coastal Areas.

June 2000

http://www.fema.gov/library/viewRecord.do?id=1671

FEMA 85 Manufactured Home Installation in Flood Hazard Areas. September 1985 http://

www.fema.gov/library/viewRecord.do?id=1577

FEMA 320 Taking Shelter From the Storm: Building a Safe Room For Your Home or Small 

Business. August 2008 

http://www.fema.gov/library/viewRecord.do?id=1536

FEMA 361 Design and Construction Guidance for Community Safe Rooms. August 2008

http://www.fema.gov/library/viewRecord.do?id=1657
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT B-9

References and FEMA Publication LIST B

FEMA 424 Design Guide for Improving School Safety in Earthquakes, Floods, and High Winds. 

January 2004 

http://www.fema.gov/library/viewRecord.do?id=1986

FEMA 431 Tornado Protection: Selecting Refuge Areas in Buildings. November 2003

http://www.fema.gov/library/viewRecord.do?id=1563

FEMA 488 Hurricane Charley in Florida: Observations, Recommendations, and Technical 

Guidance. April 2005

http://www.fema.gov/rebuild/mat/mat_fema488.shtm

FEMA 489 Hurricane Ivan in Alabama and Florida: Observations, Recommendations and 

Technical Guidance. August 2005

http://www.fema.gov/rebuild/mat/mat_fema489.shtm

FEMA 499 Home Builder’s Guide to Coastal Construction, Technical Fact Sheet Series, 31 sheets. 

August 2005

http://www.fema.gov/rebuild/mat/mat_fema499.shtm

FEMA 543 Design Guide for Improving Critical Facility Safety from Flooding and High Winds: 

Providing Protection to People and Buildings. January 2007 

http://www.fema.gov/library/viewRecord.do?id=2441

FEMA 549 Hurricane Katrina in the Gulf Coast: Building Performance Observations, 

Recommendations, and Technical Guidance. July 2006

http://www.fema.gov/library/viewRecord.do?id=1857

FEMA 550 Recommended Residential Construction for the Gulf Coast: Building on Strong and 

Safe Foundations. July 2006

http://www.fema.gov/library/viewRecord.do?id=1853

FEMA 577 Design Guide for Improving Hospital Safety in Earthquakes, Floods, and High Winds: 

Providing Protection to People and Buildings. June 2007

http://www.fema.gov/library/viewRecord.do?id=2739

FEMA 9-0372 Reducing Flood Losses Through the International Codes: Meeting the Requirements of 

the National Flood Insurance Program. December 2007 

http://www.fema.gov/library/viewRecord.do?id=2094

FEMA P-762 Local Officials Guide to Coastal Construction. February 2009

http://www.fema.gov/library/viewRecord.do?id=3647
B-10 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

B References and FEMA Publication LIST

NFIP Technical Bulletins 

http://www.fema.gov/plan/prevent/floodplain/techbul.shtm

FIA-TB-0: User’s Guide to Technical Bulletins

FIA-TB-1: Openings in Foundation Walls and Walls of Enclosures (updated 2008)

FIA-TB-2: Flood Damage-Resistant Materials Requirements (updated 2008)

FIA-TB-3: Non-Residential Floodproofing – Requirements and Certification

FIA-TB-4: Elevator Installation

FIA-TB-5: Free-of-Obstruction Requirements (updated 2008)

FIA-TB-6: Below-Grade Parking Requirements

FIA-TB-7: Wet Floodproofing Requirements

FIA-TB-8: Corrosion Protection of Metal Connectors in Coastal Areas

FIA-TB-9: Design and Construction Guidance for Breakaway Walls Below Elevated Coastal 

Buildings (updated 2008)

FIA-TB-10: Ensuring that Structures Built on Fill In or Near Special Flood Hazard Areas are 

Reasonably Safe From Flooding

FIA-TB-11: Crawlspace Construction for Buildings Located in Special Flood Hazard Areas

NFIP Evaluation Studies

http://www.fema.gov/business/nfip/nfipeval.shtm

Evaluation of the National Flood Insurance Program’s Building Standards 

http://www.fema.gov/library/viewRecord.do?id=2592

FEMA Safe Room Web Site

http://www.fema.gov/plan/prevent/saferoom/
HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT C-1

AcRONyMS ANd GlOSSARy C

CAcronyms and Glossary 

Acronyms

A

ABFE Advisory Base Flood Elevation 

ACI American Concrete Institute

AIA American Institute of Architects 

ANSI American National Standards Institute 

ARA Applied Research Associates 

ASCE American Society of Civil Engineers 

ASOS Automated Surface Observation System 

ASTM American Society for Testing and Materials 

B

BEG Bureau of Economic Geology, Texas

BFE Base Flood Elevation 

BIA Brick Industry Association

BUR Built-Up Roof
C-2 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

C Acronyms and Glossary

C

CABO Council of American Building Officials 

C&C Components and Cladding 

CDT Central Daylight Time 

CEPRA Coastal Erosion Planning and Response Act

CFD Computational Fluid Dynamics

CFR Code of Federal Regulations 

C-MAN Coastal Marine 

CO-OPS Center for Operational Oceanographic Products and Services, NOAA

CRTF Catastrophe Reserve Trust Fund 

CWPRA Coastal Wetlands Planning and Restoration Act

D

DFIRM Digital Flood Insurance Rate Map 

DHS Department of Homeland Security 

DOJ U.S. Department of Justice

E

EF Enhanced Fujita 

EIFS Exterior Insulation Finish System 

EOC Emergency Operations Center 

F

FCMP Florida Coastal Monitoring Program 

FEMA Federal Emergency Management Agency 

FIRM Flood Insurance Rate Map 

FIS Flood Insurance Study 

FLASH Federal Alliance for Safe Homes 
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT C-3

Acronyms and Glossary C

G

GLO General Land Office, Texas

H

HAZUS-MH Hazards United States Multi-Hazard 

HCFCD Harris County Flood Control District 

HMGP Hazard Mitigation Grant Program

HRD Hurricane Research Division 

HWM High Water Mark 

HUD U.S. Department of Housing and Urban Development 

HVAC Heating, Ventilation, and Air-Conditioning 

I

IBC International Building Code 

IBHS Institute for Business and Home Safety 

ICC International Code Council 

ICMA International City/County Management Association

IKE Integrated Kinetic Energy 

IPCC Intergovernmental Panel on Climate Change

IRC International Residential Code 

L

LADOTD Louisiana Department of Transportation and Development 

LED Louisiana Economic Development 

LiMWA Limit of Moderate Wave Action 

LPS Lightning Protection System

LSUCC Louisiana Statewide Uniform Construction Code Council 

LWCRA Louisiana Wetland Conservation and Restoration Authority
C-4 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

C Acronyms and Glossary

M

MAT Mitigation Assessment Team 

mb millibars 

MHCSS Manufactured Home Construction and Safety Standard

mph miles per hour 

MRGO Mississippi River Gulf Outlet

MWFRS Main Wind Force Resisting System 

N

NAHB National Association of Home Builders 

NAVD North American Vertical Datum 

NAVD 88 North American Vertical Datum of 1988

NEC National Electrical Code 

NFIP National Flood Insurance Program 

NFPA National Fire Protection Association 

NFPA 5000 NEPA Building Construction and Safety Code 

NGVD National Geodetic Vertical Datum

NHC National Hurricane Center 

NJ DEP New Jersey Department of Environmental Protection

NOAA National Oceanographic and Atmospheric Administration 

NOS National Ocean Service, NOAA 

NUPC National Underwriter and Casualty 

NWS National Weather Service 

O

OAR Office of Atmospheric Research 

OSB Oriented Strand Board
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT C-5

Acronyms and Glossary C

P

PCS Property Claim Services 

psf pounds per square foot 

PVC Poly Vinyl Chloride

R

R.S. Revised Statutes 

S

SBC Standard Building Code 

SBCCI Southern Building Code Congress International 

SDP Surge/Wave Destructive Potential 

SFHA Special Flood Hazard Area 

SGN Smart Growth Network

T

TAC Texas Administration Code 

TCPIA Texas Catastrophe Property Insurance Association 

TCR Tropical Cyclone Report 

TDI Texas Department of Insurance 

TRCC Texas Residential Construction Commission 

TTU Texas Tech University 

TWIA Texas Windstorm Insurance Association 

U

UBC Uniform Building Code 

USACE U.S. Army Corps of Engineers 
C-6 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

C Acronyms and Glossary

USGS U.S. Geological Survey 

UTC Universal Time Coordinated 

UTMB University of Texas Medical Branch

V

VSI Vinyl Siding Institute 

W

WDP Wind Destructive Potential 
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT C-7

Acronyms and Glossary C

Glossary

100-year flood – The flood elevation that has a 1-percent chance of being equaled or exceeded 

each year. 

ASCE 7 – National design standard issued by the American Society of Civil Engineers, 

Minimum Design Loads for Buildings and Other Structures, which gives current requirements for 

dead, live, soil, flood, wind, snow, rain, ice, and earthquake loads, and their combinations, 

suitable for inclusion in building codes and other documents.

ASCE 24 – National design standard issued by the American Society of Civil Engineers, Flood 

Resistant Design and Construction, which outlines the requirements for flood resistant design 

and construction of structures in flood hazard areas.

Base Flood Elevation – Elevation of the 1-percent-annual-chance flood. This elevation is 

the basis of the insurance and floodplain management requirements of the National Flood 

Insurance Program.

Building envelope – The entire exterior surface of a building, including roofs, walls, windows, 

and doors, which encloses or envelops the space within.

Capillary action – Commonly referred to as “wicking,” capillary action is the process by which 

water in liquid form climbs upward through materials in opposition to the force of gravity.

Critical and essential facilities – Facilities that, if damaged, would present an immediate threat 

to life, public health, and safety. Critical and essential facilities include, but are not limited to, 

hospitals, emergency operations centers, water systems, and utilities.

Design flood event – The greater of the following two flood events: (1) the base flood, 

affecting those areas identified as special flood hazard areas on a community’s Flood 

Insurance Rate Map (FIRM); or (2) the flood corresponding to the area designated as a flood 

hazard area on a community’s flood hazard map or otherwise legally designated.

Design wind event – An event for which the observed wind speed equaled or exceeded the 

design wind speed.

Design wind speed – The wind speed designated in ASCE 7 or the building code.

Eave – The horizontal lower edge of a sloped roof.

Erosion – Process by which floodwaters lower the ground surface in an area by removing 

upper layers of soil.

Fetch – The distance along open water or land over which the wind blows. 

Floodborne debris impact – Floodwater moving at a moderate or high velocity can carry 

floodborne debris that can impact buildings and damage walls and foundations.

Floodwall – A long, narrow concrete or masonry wall built to protect land from flooding.
C-8 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

C Acronyms and Glossary

Freeboard – The height added to place a structure above the base flood to reduce the 

potential for flooding. The increased elevation of a building above the minimum design flood 

level to provide additional protection for flood levels higher than the 1-percent-annual-chance 

flood level and to compensate for inherent inaccuracies in flood hazard mapping.

Gable end wall – The triangular end of an exterior wall above the eaves formed under a gable 

roof.

Girt – A horizontal structural member that is attached to sidewall or endwall columns and 

supports wall paneling.

Glazing – Glass or transparent or translucent plastic sheet used in windows, doors, and 

skylights.

Hem – The portion of the cleat (coping or edge flashing) that bends out at about a 60-degree 

angle at the bottom portion of the cleat/coping or edge flashing.

Hurricane – An intense tropical weather system with a well-defined counter-clockwise 

circulation and sustained winds of 74 mph or higher. 

Insulated concrete form construction – A construction technique for which the walls of the 

building are composed of hollow styrofoam blocks or foam panels, which serve as concrete 

forms that remain in place after they are reinforced and filled with concrete.

Levee – A manmade structure, usually an earthen embankment, designed and constructed in 

accordance with sound engineering practices to contain, control, or divert the flow of water so 

as to provide protection from temporary flooding.

Pier foundation – Vertical support member of masonry or cast-in place concrete that is 

designed and constructed to function as an independent structural element in supporting 

and transmitting both building loads and environmental loads to the ground. Typical pier 

foundations are constructed on footings.

Pile foundation system – Vertical support member of wood, steel, or precast concrete that is 

driven or jetted into the ground and supported primarily by friction between the pilings and 

surrounding earth. Pilings often cannot act as independent support units and, therefore, are 

often braced with connections to other pilings. 

Pole construction – A type of construction for which the pilings extend from the ground to the 

roof system. It differs from platform construction for which the pilings terminate at the lowest 

floor.

Purlin – A horizontal structural member that supports roof covering and carries loads to the 

primary framing members.

Rake – The inclined edge of a sloped roof over a wall.

Reinforced concrete – Concrete with steel mesh or bars embedded in it to increase its tensile 

strength.
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT C-9

Acronyms and Glossary C

Saffir-Simpson Scale – Measures a hurricane’s intensity on a 1–5 scale to give an estimate of 

the potential property damage and flooding expected. Wind speed is the determining factor 

in the scale. A Category 1 hurricane is the weakest, with winds from 74–95 mph (maximum, 

1-minute sustained speeds), and a Category 5 hurricane is the strongest, with winds over 155 

mph. Refer to Table 1-2.

Slab-on-grade foundation – Type of foundation for which the lowest floor of the house is 

formed by a concrete slab that sits directly on the ground. 

Soffit – The underside of a horizontal element of a building, especially the underside of a stair 

or a roof overhang.

Special Flood Hazard Area – Portion of the floodplain subject to inundation by the base flood.

Steel moment frame – In steel moment frame buildings, the ends of the beams are rigidly 

joined to the columns so that the buildings can resist lateral wind forces without the assistance 

of additional braces or walls.

Stem wall foundation – A type of foundation that uses masonry block and is reinforced with 

steel and concrete. The wall is constructed on a concrete footing, back-filled with dirt, and 

compacted, and then the slab is poured on top.

Storm surge – The water that is pushed toward land from the high winds of a major storm 

(i.e., hurricane).

Tropical storm – A tropical cyclone with maximum sustained (1-minute average) winds of 39 

to 73 mph.

HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT D-1

HuRRIcANE IkE REcOvERy AdvISORIES D

Hurricane Ike Recovery 

Advisories

FEMA has prepared a series of Recovery Advisories that present guidance for design, construction, 

and restoration of buildings in areas subject to coastal flooding and high winds from Hurricane 

Ike. To date, eight advisories have been prepared and are included in this appendix:

n Attachment of Brick Veneer in High-Wind Regions ([December, 2005]; revised 2009)

n Design and Construction in Coastal A Zones ([December, 2005]; revised 2009)

n Designing for Flood Levels above the BFE ([July, 2006]; revised 2009)

n Enclosures and Breakaway Walls

n Erosion, Scour, and Foundation Design

n Minimizing Water Intrusion Through Roof Vents in High-Wind Regions

n Metal Roof Systems in High-Wind Regions

n Siding Installation in High-Wind Regions

These Advisories are also available online at http://www.fema.gov/library/viewRecord.do?id=3539

where future Advisories will also be posted. 

DHurricane Ike Recovery 

Attachment of Brick Veneer in 

High-Wind Regions

HURRICANE IKE RECOVERY ADVISORY

Attachment of Brick Veneer in High-Wind Regions February 2009 Page 1 of 4

Purpose: To recommend practices for installing brick veneer that will enhance wind resistance in high-wind 

areas (i.e., greater than 90-mph gust design wind speed).

Key Issues

•	Brick veneer is frequently blown off walls of residential and

non-residential buildings during hurricanes (Figure 1). When 

brick veneer fails, wind-driven water can enter and damage 

buildings, and building occupants can be vulnerable to injury

from windborne debris (particularly if walls are sheathed with

plastic foam insulation or wood fiberboard in lieu of wood 

panels). Pedestrians in the vicinity of damaged walls can also

be vulnerable to injury from falling veneer (Figure 2).

•	Common failure modes include tie (anchor) corrosion (Figure

3), tie fastener pull-out (Figure 4), failure of masons to embed 

ties into the mortar (Figure 5), and poor bonding between ties 

and mortar and mortar of poor quality (Figure 6).

•	Ties are often installed before brick laying begins. When this

is done, ties are often improperly placed above or below the

mortar joints. When misaligned, the ties must be angled up 

or down in order for the ties to be embedded into the mortar 

joints (Figure 7). Misalignment not only reduces embedment

depth, but also reduces the effectiveness of the ties because 

wind forces do not act parallel to the ties themselves.

•	Corrugated ties typically used in residential veneer

construction provide little resistance to compressive loads. 

Use of compression struts would likely be beneficial,

but off-the-shelf devices do not currently exist. Two-piece

adjustable ties (Figure 8) provide significantly greater

compressive strength than corrugated ties and are, therefore, 

recommended. However, if corrugated ties are used, it is 

recommended that they be installed as shown in Figures 9

and 10 in order to enhance their wind performance.

Figure 1. Failed brick veneer over plywood. Many 

of the ties are still attached to the substrate, 

but several of the tie fasteners pulled out of the 

substrate and the ties are embedded in the collapsed 

veneer. Estimated wind speed: 107 miles per hour 

(peak gust, Exposure C, at 33 feet).

Figure 2. The upper portion of the brick veneer at 

this apartment building collapsed. Pedestrian and 

vehicular traffic in the vicinity of the damaged wall are 

vulnerable to injury and damage if remaining portions 

of the wall were to collapse during subsequent storms.

Figure 3. Significant tie corrosion caused the brick at a fire station to 

fail, even though the building is not near the coast. Note that metal 

is missing for half of of width of the tie at two locations (red arrows). 

The left end of the tie was still embedded into a concrete masonry 

unit back-up wall. The right end is where the tie failed in tension, thus 

leaving a portion of the tie embedded in the collapsed brick.

http://www.fema.gov
Attachment of Brick Veneer in High-Wind Regions February 2009 Page 2 of 4

•	Buildings that experience veneer damage typically do

not comply with current building codes. Building code

requirements for brick veneer have changed over the years.

Model codes prior to 1995 permitted brick veneer in any

location, with no wind speed restrictions. Also, some older 

model codes allowed brick veneers to be anchored with fewer 

ties than what is required by today’s standards.

	 The American Concrete Institute’s (ACI’s) 530/American

Society of Civil Engineers (ASCE) 5/The Masonry Society

(TMS) 402 (ACI 530) Building Code Requirements for Masonry 

Structures is the current masonry standard referenced by

model building codes. The 2006 International Building Code®

(IBC®) and the 2006 International Residential Code®(IRC®)

both reference the 2005 edition of ACI 530. The latest ACI

530 is the 2008 edition.

	 ACI 530 addresses brick veneer in two manners: rational

design and a prescriptive approach. Nearly all brick veneer in

residential and low-rise construction follows the prescriptive 

approach. The first edition of ACI 530 limited the use of

prescriptive design to areas with a basic wind speed of 110 

mph or less. The 2005 and the 2008 editions of ACI 530

extend the prescriptive requirements to include a basic wind

speed of 130 mph, but limit the amount of brick that can 

be anchored with veneer ties to 70 percent of that allowed 

in lower wind speed regions. Both the 2005 and the 2008

editions require rational design approaches in locations

where the basic wind speeds exceed 130 mph.

	 Some noteworthy distinctions exist in the requirements for

anchored brick veneer between the 2005 and the 2008

editions of ACI 530. For lower wind speed regions (110 mph

and below), ACI 530-05 limited the vertical spacing of ties to

18"; the 2008 edition allows vertical ties to be spaced up to

25", provided the amount of veneer anchored per tie does

not exceed 2.7 square feet. In ACI’s high-wind regions (over

110 mph and up to 130 mph), both editions of the code limit 

vertical spacing to 18". ACI 530-08 also limits the space

between veneer anchored with corrugated ties and the wall 

sheathing to 1". This is to avoid compression failures in the 

corrugated ties when they are exposed to positive pressures.		

Figure 7. Misalignment of the tie reduces the embedment and promotes veneer 

failure.

Figure 6. This tie was embedded in the mortar, but the 

bond was poor.

Figure 5. These four ties were never embedded into 

the mortar joint.

Figure 8. Examples of two-piece adjustable 

ties.

Figure 4. This tie remained embedded in the mortar 

joint while the smooth-shank nail pulled out from the 

stud.
Attachment of Brick Veneer in High-Wind Regions February 2009 Page 3 of 4

•	The following Brick Industry Association (BIA) Technical

Notes provide guidance on brick veneer: Technical Notes

28 – Anchored Brick Veneer, Wood Frame Construction;

Technical Notes 28B – Brick Veneer/Steel Stud Walls;

and Technical Notes 44B – Wall Ties (available online

at http://www.bia.org). These Technical Notes provide

attachment recommendations, but the recommendations 

are not specific for high-wind regions and are, therefore, 

inadequate.

Construction Guidance

The brick veneer wall system is complex in its behavior. There are limited test data on which to draw.

The following guidance is based on professional judgment, wind loads specified in ASCE 7-05, Minimum 

Design Loads for Buildings and Other Structures, fastener strengths specified in the American Forest and 

Paper Association’s (AF&PA’s) National Design Specification (NDS) for Wood Construction, and brick veneer

standards contained in ACI 530-05. In addition to the general guidance given in BIA Technical Notes 28 and

28B, the following are recommended:

Note: In areas that are also susceptible to high seismic loads, brick veneer should be evaluated by an

engineer to ensure it can resist seismic and wind design loads.

Stud Spacing: For new construction, space studs 16" on center, so that ties can be anchored at this spacing.

Tie Fasteners: Ring-shank nails are recommended in lieu of smooth-shank nails. A minimum embedment of 2"

into framing is suggested. 

Ties: For use with wood studs, two-piece adjustable ties are recommended. However, where corrugated steel

ties are used, use 22-gauge minimum, 7/8" wide by 6" long, complying with American Society for Testing and

Materials (ASTM) A 366 with a zinc coating complying with ASTM A 153 Class B2. For ties for use with steel

studs, see BIA Technical Notes 28B – Brick Veneer/Steel Stud Walls. Stainless steel ties should be used in

areas within 3,000 feet of the coast.

Tie Installation 

•	Install ties as the brick is laid so that the ties are

properly aligned with the mortar joints.

•	Install brick ties spaced per Table 1. Studs should be

installed at 16" spacing. Veneer tie locations for 24"

stud spacing are included for repairing damaged veneer 

on existing buildings with the wider stud spacing. In areas

where the 2006 Editions of the IBC/IRC are adopted,

install brick veneer ties spaced no more than 18" 

vertically to satisfy the requirements of ACI 530-05.

•	Locate ties within 8" of door and window openings and

within 12" of the top of veneer sections.

•	Bend the ties at a 90-degree angle at the nail head in

order to minimize tie flexing when the ties are loaded in

tension or compression (Figure 9).

•	Embed ties in joints so that mortar completely

encapsulates the ties. Embed a minimum of 1 1/2" into

the bed joint, with a minimum mortar cover of 5/8" to the

outside face of the wall (Figure 10). 

Figure 10. Tie embedment.

Figure 9. Bend ties at nail heads.

Sustainability 

Brick veneer can offer a very long service

life, provided the ties are not weakened by

corrosion. To help ensure that brick veneer 

achieves its long life potential, in addition 

to properly designing and installing the ties,

stainless steel ties are recommended.
Attachment of Brick Veneer in High-Wind Regions February 2009 Page 4 of 4

Table 1. Brick Veneer Tie Spacing

Wind Speed (mph)

(3–Second Peak Gust) Wind Pressure (psf) Maximum Vertical Spacing for Ties (inches)

16" stud spacing 24" stud spacing

 90 –19.5 24a,b 16a

100 –24.1 24a,b 16a

110 –29.1 201⁄2 b 131⁄2

120 –34.7 17 NAc

130 –40.7 15 NAc

140 –47.2 13 NAc

150 –54.2 11 NAc

Notes:

1. The tie spacing is based on wind loads derived from Method 1 of ASCE 7-05, for the corner area of buildings up to 30' high, located in Exposure

B with an importance factor (I) of 1.0 and no topographic influence. For other heights, exposures, or importance factors, engineered designs are

recommended.

2.	Spacing is for 21⁄2" long 8d common (0.131" diameter) ring-shank fasteners embedded 2" into framing. Fastener strength is for wall framing with

a Specific Gravity G=0.55 with moisture contents less than 19 percent and the following adjustment factors, Ct=0.8; and CD, CM, Ceg, and Ctn=1.0. 

Factored withdrawal strength W'= 65.6#.

3.	The brick veneer tie spacing table is based on fastener loads only and does not take into account the adequacy of wall framing, sheathing, and other

building elements to resist wind pressures and control deflections from a high-wind event. Prior to repairing damaged brick veneer, the adequacy of

wall framing, wall sheathing, and connections should be verified by an engineer.

a 	Maximum spacing allowed by ACI 530-08.

b 	In locales that have adopted the 2006 IBC/IRC, the maximum vertical spacing allowed by ACI 530-05 is 18".

c 	 24" stud spacing exceeds the maximum horizontal tie spacing of ACI 530-08 prescribed for wind speeds over 110 mph.
HURRICANE IKE RECOVERY ADVISORY

Design and Construction in Coastal A Zones January 2009 Page 1 of 5

Purpose: To recommend design and construction practices in coastal areas where wave and flood conditions 

during the base flood will be less severe than in V zones, but still cause significant damage to typical lightframe construction.

Key Issues

•	Recent post-storm investigations have shown that

typical A-zone construction techniques (e.g., woodframe, light gauge steel, or masonry walls on shallow 

footings or slabs, etc.) are subject to damage or 

destruction when exposed to less than 3' waves, 

which is the current threshold for V-zone conditions.

•	Coastal A-zone buildings that employ typical

residential and light commercial walls to elevate and 

support habitable space above the flood level will be 

susceptible to flood damage (Figure 1). Laboratory 

tests and recent field investigations confirm that 

breaking wave heights as small as 1.5' will cause 

failure of these types of walls (Figure 2).

•	Other flood hazards associated with coastal waves

(e.g., floating debris, high velocity flow, erosion and 

scour) also damage A-zone type construction in 

coastal areas (Figure 3). 

•	National Flood Insurance Program (NFIP) flood hazard

mapping is generally divided into two categories, V 

and A zones. In coastal areas, the A-zone category

could be subdivided into “Coastal A zone” and “A

Design and Construction 

in Coastal A Zones

Coastal A Zone, Defined 

Coastal A Zone: area landward of a V zone, or landward of 

an open coast without mapped V zones. In a Coastal A zone,

the principal source of flooding will be astronomical tides, 

storm surges, seiches or tsunamis, not riverine flooding. 

During base flood conditions, the potential for wave heights 

between 1.5 and 3.0' will exist. At least 2 to 4' of stillwater 

depth is necessary to support these wave heights.

Coastal A-zone design and construction practices described

herein are not mandated by the NFIP, but are recommended

for communities that wish to adopt higher floodplain 

management standards. Community Rating System (CRS)

credits are available for doing so. Note that some Coastal

A-zone practices may be required by the International

Building Code®, through its reference to ASCE 24, Standard 

for Flood Resistant Design and Construction.

Figure 1. Failure of wood-frame walls used to support a coastal 

building, which was subjected to shallow flooding, small waves, 

and floating debris (Fort Walton Beach, FL, Hurricane Opal). 

Plan view showing a Coastal A zone landward of a V 

zone (source: ASCE 24-05).

The Hurricane Ike Mitigation Assessment Team

(MAT) observed small wave damage consistent

with Coastal A-zone conditions throughout

the area affected by Ike, including portions of

west Galveston Island (Figure 4), communities

situated along portions of Galveston Bay (Figure 

5), Orange County (Figure 6), and portions of

coastal Louisiana (Figure 7). 

http://www.fema.gov
Design and Construction in Coastal A Zones January 2009 Page 2 of 5

zone.” Base flood conditions in the Coastal A zone

will be similar to, but less severe than, those in the 

V zone; base flood conditions in the A zone will be 

similar to those in riverine or lake floodplains. 

•	The Coastal A zone is not shown on the Flood

Insurance Rate Maps (FIRMs) presently adopted by

communities. Communities, designers, and owners

will have to determine whether a site lies within a 

Coastal A zone, either by wave height estimation or by

consultation with FEMA regarding the LiMWA (see text box).

•	In general, V-zone design and construction standards are recommended in Coastal A zones subject to 

erosion, high velocity flow, and/or wave heights greater than 1.5'.

Figure 2. Failure of wood-frame wall, brick veneer, and 

windows as a result of 4' of stillwater flooding and small 

waves (Bay St. Louis, MS, Hurricane Katrina). 

Figure 3. Failure of A-zone type foundation in coastal area, 

not subject to V-zone conditions (Topsail Island, NC, Hurricane 

Fran). 

Figure 4. Coastal A-zone flood conditions are sufficient to 

cause failure of solid breakaway walls and garage doors (west 

Galveston Island, TX, Hurricane Ike). 

Figure 5. Damage to 

brick veneer walls due to 

shallow flooding, floating 

debris, and small waves. 

The damaged home 

was on a sheltered bay 

shoreline (Baytown, TX, 

Hurricane Ike). 

Flood insurance studies produced after 

Hurricane Katrina may include an advisory 

line indicating the limit of the 1.5' wave height 

during the base flood. This line is known as 

the Limit of Moderate Wave Action (LiMWA),

and the area between this line and the VE zone

boundary is the Coastal A zone.
Design and Construction in Coastal A Zones January 2009 Page 3 of 5

Coastal A-Zone Construction Guidance

Because of the presence of damaging waves, V-zone design, construction, and certification practices are 

recommended for Coastal A zones.

Coastal A-zone construction should include:

•	Use of open foundations (pile or pier) designed

to resist all base flood conditions, including small 

waves, high velocity flow, erosion and scour, and 

floodborne debris (see Table 1).

•	Elevation of the bottom of the lowest horizontal

structural member supporting the lowest floor above 

the base flood wave crest elevation (Figure 8). Since

waves and debris will be impacting on the floor joists 

and other foundation elements during the base flood, 

do not follow current NFIP minimum requirements

that allow the lowest floor’s walking surface to be 

set at the wave crest elevation in Zone A. The 2009 

International Residential Code® (IRC®) will require 

1' of freeboard in V zones and Coastal A zones.

•	Use of flood-resistant materials above the level of the

walking surface of the lowest floor (in the event that future flooding exceeds the lowest floor level and any 

freeboard incorporated into the building design).

•	Specification of connections between the foundation and the elevated building that are capable of

withstanding simultaneous wind and flood forces. Post-hurricane investigations typically find many

foundation-to-building connections that are deficient.

•	Use of space below the lowest horizontal structural member for parking, access, or storage only. Adding

sufficient freeboard to allow parking beneath the building will not only reduce future flood damages, but will 

also lower flood insurance premiums.

Figure 8. Recommended post-Katrina building standards in 

Coastal A zones.

Figure 6. Damage attributed to small waves and approximately 

5' of stillwater depth (Bridge City, TX, Hurricane Ike). 

Figure 7. Damage believed to have resulted from Coastal 

A-zone conditions (Johnson Bayou, LA, Hurricane Ike).
Design and Construction in Coastal A Zones January 2009 Page 4 of 5

•	Use of screen, lattice, louvers, or solid breakaway walls if space below the elevated floor is enclosed (see

Hurricane Ike Recovery Advisory, Enclosures and Breakaway Walls). Note: unless flood regulations are

changed, solid breakaway walls in Coastal A zones must be equipped with flood openings.

Additional guidance for design and construction in Coastal A zones can be found in FEMA 499, Home Builder’s 

Guide to Coastal Construction (http://www.fema.gov/library/viewRecord.do?id=1570). The publication is 

a series of 31 fact sheets that provide recommended design and construction practices for foundations, 

connections, building envelope, etc. Fact Sheet 2 summarizes recommended practices for Coastal A zones,

and references other fact sheets that provide more details. 

Identifying Coastal A Zones

Coastal A zones are not shown on present day FIRMs or mentioned in a community’s Flood Insurance Study

(FIS) Report. Those maps and studies show Zones VE, AE, and X (or older designations V1-30, A1-30, B,

and C). Therefore, until Coastal A-zone designations or wave height contours are incorporated into FISs, the

community official, designer, or owner will have to determine whether or not a site will be subject to Coastal

A-zone conditions during the base flood. 

In order for a Coastal A zone to be designated, two conditions are required:

1) a water depth sufficient to support waves between 1.5 and 3.0' high, and 

2) the actual presence of wave heights between 1.5 and 3.0'. 

Condition 1 requires stillwater depths (vertical distance between the 100-year stillwater elevation and the

ground elevation) of at least 2 to 4' at the site. 

Condition 2 requires wave heights at the shoreline greater than 1.5 to 3.0' (under the 100-year flood

conditions), sufficient water depth between the shoreline and the site and few, if any obstructions (buildings, 

dense tree stands, etc.) that may block or dampen the waves, between the shoreline and the site. 

Figure 9 illustrates the procedure that was used following Hurricane Katrina to estimate Advisory Base Flood

Elevations (ABFEs) and corresponding Coastal A zones, knowing only the ground elevation and the 1-percent

annual chance stillwater level.

Foundation Type

Base Flood Condition Present

Wave Heights Between 

1.5 and 3.0 Feet* Velocity Flow, Erodible Soils

Fill no no

Slab on grade no no

Crawlspace, shallow footing no no

Foundation walls, shallow footing no no

Stem wall** no no

Pier, shallow footing yes no

Pier, deep footing*** yes yes

Post, shallow embedment no no

Pile/Column, deep embedment*** yes yes

* Wave heights greater than 3.0' mapped as V zone: fill, slab, crawlspace, wall foundations not permitted.

** Typical stem wall foundations are vulnerable to damage from small waves or undermining and are, therefore, not recommended 

for use in Coastal A zones.

*** Deep means sufficiently deep to withstand erosion and scour, including that induced by the presence of the foundation itself.

Table 1. Foundation Recommendations for Coastal A Zones (Users should read across from a foundation

type to see under what soil and base flood conditions that foundation is acceptable. A foundation must 

be capable of resisting all base flood conditions likely to exist at the site, or it should not be used. For 

example, a properly constructed pier on a shallow footing will generally withstand 1.5 to 3.0' wave heights, 

but should not be used where soils are erodible, and where high velocity flow is possible.)
Design and Construction in Coastal A Zones January 2009 Page 5 of 5

Communities, designers, and owners can

obtain the information necessary to make 

a post-Ike Coastal A-zone determination by

observing the site and its surroundings, 

knowing site ground elevations, and 

using 1-percent annual chance stillwater 

elevations (from the FIS report or as

determined by a government agency). 

Figure 10 shows how site and surrounding 

conditions would influence a Coastal-A

zone determination. 

Figure 9. Post-Katrina Coastal A-zone methodology cross-section showing 1 

percent annual chance stillwater elevation, stillwater depth and ABFE, and 

inland limits of an V zone and a Coastal A zone.

Figure 10. The site on the left is mapped Zone AE, and lies directly along the Gulf of Mexico shoreline. Limited obstructions to waves 

indicate the site could be classified as a Coastal A zone. The site on the right is over 1⁄2 mile from the Gulf shoreline, is mapped as 

Zone AE, and has a base flood stillwater level sufficient to support >1.5' wave heights -- but obstructions to waves (e.g., trees and 

other buildings between the site and the shoreline) and distance from the source of flooding would indicate the area is not a Coastal 

A zone.

 

 

References

ASCE. 2005. Standard for Flood Resistant Design and Construction, ASCE 24-05. 

FEMA. 2005. Home Builder’s Guide to Coastal Construction, FEMA 499.

FEMA. 2009. Hurricane Ike Recovery Advisory, Enclosures and Breakaway Walls. 

ICC 2006. International Building Code. 2006.

ICC 2009. International Residential Code. 2009.

HURRICANE IKE RECOVERY ADVISORY

Designing for Flood Levels

Above the BFE

Designing for Flood Levels Above the BFE March 2009 Page 1 of 8

Purpose: To recommend design and construction practices that reduce the likelihood of flood damage in the 

event that flood levels exceed the Base Flood Elevation (BFE).

Key Issues

• BFEs are established at a flood level, including wave effects, that has a 1-percent chance of being equaled 

or exceeded in any given year, also known as the 100-year flood or base flood. Floods more severe and 

less frequent than the 1-percent flood can occur in any year.

• Flood levels during some recent storms have 

exceeded BFEs depicted on the Flood Insurance Rate 

Maps (FIRMs), sometimes by several feet. In many 

communities, flooding extended inland, well beyond 

the 100-year floodplain (Special Flood Hazard Area 

(SFHA)) shown on the FIRM (see Figure 1).

• Flood damage increases rapidly once the elevation of 

the flood extends above the lowest floor of a building, 

especially in areas subject to coastal waves. In a V 

zone, a coastal flood with a wave crest 3 to 4' above 

the bottom of the floor beam (approximately 1 to 2 

feet above the walking surface of the floor) will be 

sufficient to substantially damage or destroy most 

light-framed residential and commercial construction 

(see Figure 2). 

• There are design and construction practices that 

can eliminate or minimize damage to buildings when 

flood levels exceed the BFE. The most common 

approach is to add freeboard to the design (i.e., 

to elevate the building higher than required by the 

FIRM).

• There are other benefits of designing for flood 

levels above the BFE: reduced building damage and 

maintenance: longer building life; reduced flood 

insurance premiums; reduced displacement and 

dislocation of building occupants after floods (and 

need for temporary shelter and assistance); reduced 

job loss; and increased retention of tax base. 

• The cost of adding freeboard at the time of home 

construction is modest, and reduced flood insurance 

premiums will recover the freeboard cost in a few 

years time.

How High Above the BFE Should a Building be Elevated?

Ultimately, the building elevation will depend on several factors, all of which must be considered before a final 

determination is made:

Figure 1. Bridge City, TX, homes were flooded during Ike, even 

though they were constructed outside the SFHA and in Zone B. 

The flood level was approximately 4' above the closest BFE. 

Figure 2. Bolivar Peninsula, TX, V-zone house constructed with 

the lowest floor (bottom of floor beam) at the BFE (dashed 

line). The estimated wave crest level during Ike (solid line) was 

3 to 4' above the BFE at this location.

http://www.fema.gov
Designing for Flood Levels Above the BFE March 2009 Page 2 of 8

• The accuracy of the BFE shown on the FIRM: If the BFE is suspect, it is probably best to elevate several feet 

above the BFE; if the BFE is deemed accurate, it may only be necessary to elevate a couple of feet above 

the BFE.

• Availability of Advisory Base Flood Elevations (ABFEs): ABFEs have been produced for coastal areas following 

Hurricanes Ivan, Katrina, and Rita. These elevations are intended to be interim recommendations until new 

FISs can be completed. 

• Availability of Preliminary Digital Flood Insurance Rate Maps (DFIRMS): As new Flood Insurance Studies 

(FISs) are completed for Louisiana and Texas communities, preliminary DFIRMs will be produced and 

available for use, even before they are officially adopted by those communities.

• Future conditions: Since the FIRM reflects conditions at the time of the FIS, some owners or jurisdictions 

may wish to consider future conditions (such as sea level rise, subsidence, wetland loss, shoreline erosion, 

increased storm frequency/intensity, and levee settlement/failure) when they decide how high to elevate. 

• State or local requirements: The State or local jurisdiction may require a minimum freeboard through its 

floodplain management requirements or building code.

• Building code requirements: The International Building Code® (IBC®) requires buildings be designed and 

constructed in accordance with American Society of Civil Engineers (ASCE) 24 (Standard for Flood Resistant 

Design and Construction). ASCE 24 requires between 0 and 2' of freeboard, depending on the building 

importance and the edition of ASCE 24 referenced.1 The 2009 IRC will require 1 foot of freeboard in V and 

Coastal A zones.

• Critical and essential facilities: Given the importance of these facilities, some of which must remain 

operational during a hurricane, they should be elevated higher than commercial and residential buildings.

• Building owner tolerance for damage, displacement, and downtime: Some building owners may wish to avoid 

building damage and disruption, and may choose to elevate far above the BFE.

The Hurricane Ike MAT report recommends that critical and essential facilities be elevated to the 500-year 

flood elevation or to the requirements of ASCE 24-05, whichever is higher. This recommendation may also be 

appropriate for residential and commercial structures, as well. 

The 500-year wave crest elevation can be approximated 

as 1.5 times the 500-year stillwater depth (500-year 

stillwater elevation minus the ground elevation) added 

to the ground elevation. This procedure is similar to the 

procedure used to calculate ABFEs, but with a different 

stillwater level. 

Flood Insurance Rate Maps and Flood Risk

Hurricanes Ivan (2004), Katrina (2005), Rita (2005), and Ike (2008) have demonstrated that constructing a building 

to the minimum National Flood Insurance Program (NFIP) requirements – or constructing a building outside the 

SFHA shown on the FIRMs – is no guarantee that the building will not be damaged by flooding. This is due to two 

factors: 1) flooding more severe than the base flood occurs, and 2) some FIRMs, particularly older FIRMs, may no 

longer depict the true base flood level and SFHA boundary.

Even if the FIRM predicted flood levels perfectly, buildings constructed to the elevations shown on the FIRM will 

offer protection only against the 1-percent annual chance flood level (BFE). Some coastal storms will result in 

If the 500-year stillwater elevation (feet North 

American Vertical Datum of 1988 [NAVD] or 

feet National Geodetic Vertical Datum of 1929 

[NGVD]) is not available, a rule of thumb can be 

used to approximate it as 1.25 times the 100-

year stillwater elevation (feet NAVD or feet NGVD).

MAT Elevation Recommendation

The Hurricane Ike MAT recommends new and reconstructed residential and commercial buildings be 

elevated above the effective BFEs with freeboard equal to that specified in ASCE 24-05, plus 3 feet. Once 

new DFIRMs are available and adopted, the MAT recommends new and reconstructed residential and 

commercial buildings be elevated to or above the freeboard elevation specified by ASCE 24-05. Critical 

and essential facilities should be elevated higher than residential and commercial buildings. 

1 The 1998 edition of ASCE 24 is referenced by the 2003 edition of the IBC, and requires between 0 and 1' of freeboard. The 2005 

edition of ASCE 24 is referenced by the 2006 edition of the IBC, and requires between 0 and 2' of freeboard.
Designing for Flood Levels Above the BFE March 2009 Page 3 of 8

flood levels that exceed the BFE, and buildings 

constructed to the minimum elevation could 

sustain flood damage. The black dashed line 

in Figure 3 shows the probability that the level 

of the flood will exceed the 100-year flood level 

during time periods between 1 year and 100 

years; there is an 18-percent chance that the 

100-year flood level will be exceeded in 20 

years, a 39-percent chance it will be exceeded 

in 50 years, and a 51-percent chance it will 

be exceeded in 70 years. As the time period 

increases, the likelihood that the 100-year flood 

will be exceeded also increases.

Figure 3 also shows the probabilities that 

floods of other severities will be exceeded. For 

example, taking a 30-year time period where 

there is a 26-percent chance that the 100-

year flood level will be exceeded, there is an 

18-percent chance that the 150-year flood will 

be exceeded, a 14-percent chance that the 

200-year flood will be exceeded, and a 6-percent 

chance that a flood more severe than the 500-year flood will occur.

FIRMs depict the limits of flooding, flood elevations, and flood hazard zones during the base flood. As seen in Figure 

3, buildings elevated only to the BFEs shown on the FIRMs have a significant chance of being flooded over a period 

of decades. Users should also be aware that the flood limits, flood elevations, and flood hazard zones shown on the 

FIRM reflect ground elevations, development, and flood conditions at the time of the FIS.2

Consequences of Flood Levels Exceeding the BFE

Buildings are designed to resist most environmental hazards 

(e.g., wind, seismic, snow, etc.), but are generally designed to 

avoid flooding by elevating the building above the anticipated flood 

elevation. The difference in design approach is a result of the 

sudden onset of damage when a flood exceeds the lowest floor 

elevation of a building. Unlike wind – where exposure to a wind 

speed slightly above the design speed does not generally lead to 

severe building damage – occurrence of a flood level even a few 

inches above the lowest floor elevation generally leads to significant 

flood damage, therefore, the recommendation to add freeboard. 

This is especially true in cases where waves accompany 

coastal flooding. Figure 4 illustrates the expected flood damage 

(expressed as a percent of a building’s pre-damage market 

value) versus flood depth above the bottom of the lowest 

horizontal structural member supporting the lowest floor (e.g., 

bottom of the floor beam), for a V-zone building and for a riverine 

A-zone building.3

One striking difference between the two curves is that a V-zone flood depth (wave crest elevation) 3 to 4' 

above the bottom of the floor beam (or approximately 1 to 2' above the top of the floor) is sufficient to cause 

substantial (>50 percent) damage to a building. In contrast, A zone riverine flooding (without waves and high 

velocity) can submerge a structure without causing substantial damage. This difference in building damage is 

a direct result of the energy contained in coastal waves striking buildings – something obvious to those who 

saw the wave damage that Hurricane Ike caused in Texas and Louisiana (see Figure 5).

Figure 3. Probability that a flood will exceed the n-year flood level over a given 

period of time. (Note: this analysis assumes no shoreline erosion, and no increase 

in sea level or storm frequency/severity over time.)

FIRMs do not account for the following:

• Shoreline erosion, wetland loss, 

subsidence, and relative sea level rise

• Upland development or topographic 

changes

• Degradation or settlement of levees 

and floodwalls

• Changes in storm climatology 

(frequency and severity)

• The effects of multiple storm events

Thus, what was once an accurate 

depiction of the 100-year floodplain and 

flood elevations may no longer be so.

2 Sections 7.8.1.3 and 7.9 of FEMA’s Coastal Construction Manual (FEMA 55, 2000 edition) provide guidance on evaluating a FIRM to 

determine whether it still provides an accurate depiction of base flood conditions, or whether it is obsolete.

3 Since the normal floor reference for A-zone buildings is the top of the lowest floor, the A-zone curve was shifted for comparison with 

the V-zone curve.
Designing for Flood Levels Above the BFE March 2009 Page 4 of 8

In cases where buildings are situated behind levees, a levee failure can result in rapid flooding of the area. 

Buildings near a levee breach may be exposed to high velocity flows, and damages to those buildings will 

likely be characterized by the V-zone damage curve in Figure 4. Damages to buildings farther away from the 

breach will be a result of inundation by floodwaters, and will likely resemble the A-zone curve in Figure 4.

Figure 5. Hurricane Ike damage to buildings. The upper left and upper right photos are of buildings that were close to the Gulf of Mexico shoreline and 

subjected to storm surge and large waves above the lowest floor. The lower left photo is of a building close to Galveston Bay shoreline and subjected to 

storm surge and small waves. The lower right photo is of a Cameron Parish, Louisiana, school that was approximately 1.3 miles from the Gulf shoreline, but 

subjected to storm surge and small waves.

Figure 4. Flood depth versus building damage curves for 

V zones and riverine A zones (Source: FEMA 55, Coastal 

Construction Manual).

Depth in Feet Relative to

Bottom of Lowest Horizontal Structural Member*

* Assumes distance between top of floor and bottom of lowest

 horizontal structural member = 2' for A Zone buildings.
Designing for Flood Levels Above the BFE March 2009 Page 5 of 8

Historical Wave

Crest Elevation

Historical Stillwater

Flood Depth

Historical Stillwater Elevation

(Above 100-year Stillwater)

General Recommendations

The goal of this Advisory is to provide methods to 

minimize damage to buildings in the event that coastal 

flood levels rise above the BFE. Achieving this goal 

will require adherence to one or more of the following 

general recommendations:

• In all areas where flooding is a concern, inside and 

outside the SFHA, elevate the lowest floor so that the 

bottom of the lowest horizontal structural member 

is at or above the Design Flood Elevation (DFE). Do 

not place the top of the lowest floor at the DFE, 

since this guarantees flood damage to wood floor 

systems, wood floors, floor coverings, and lower 

walls during the design flood, and may lead to mold/

contamination damage (see Figure 6).

• In flood Zones V and A, use a DFE that results in 

freeboard (elevate the lowest floor above the BFE) 

(see Figure 7). 

• In flood Zones V and A, calculate design loads and 

conditions (hydrostatic loads, hydrodynamic loads, 

wave loads, floating debris loads, and erosion and 

scour) under the assumption that the flood level 

will exceed the BFE. 

•In an A zone subject to moderate waves (1.5 to 

2.9 ft high) and/or erosion (i.e., a Coastal A zone), 

use a pile or column foundation (see Figure 7). 

See the Hurricane Ike Recovery Advisory at http://

www.fema.gov/library/viewRecord.do?id=3539 for 

details on Coastal A zones. 

• Outside the SFHA (in flood Zones B, C, and X), adopt 

flood-resistant design and construction practices if 

historical evidence or a review of the available flood 

data shows the building could be damaged by a 

flood more severe than the base flood (see 

Figure 8).

• Design and construct buildings using the latest 

model building code, ASCE 7-05, Minimum Design 

Loads for Buildings and Other Structures and ASCE 

24-05, Standard for Flood Resistant Design and 

Construction. 

• Follow the recommendations in FEMA 499, Home 

Builder’s Guide to Coastal Construction Technical 

Fact Sheets Series (available at: http://www.fema.

gov/rebuild/mat/mat_fema499.shtm). 

• Use the pre-engineered foundations shown in FEMA 

550, Recommended Residential Construction for the 

Gulf Coast: Building on Strong and Safe Foundations

(available at: http:\\www.fema.gov\library\

viewRecord.do?id=1853).

• Use strong connections between the foundation and 

the elevated building to prevent the building from 

floating or washing off the foundation, in the event 

that flood levels do rise above the lowest floor.

Figure 6. Other concerns when flood levels rise above the lowest 

floor are mold and biological/chemical contamination. These may 

render an otherwise repairable building unrepairable, or will at least 

make the cleanup, restoration, and repairs much more expensive 

and time-consuming.

Figure 7. Recommended construction in Coastal A zones and V 

zones.

Figure 8. Recommended construction in Zones B, C, and X.
Designing for Flood Levels Above the BFE March 2009 Page 6 of 8

• Use flood damage-resistant building materials and methods above the lowest floor. For example, consider 

using drainable, dryable interior wall assemblies (see Figure 9). This allows interior walls to be opened up 

and dried after a flood above the lowest floor, minimizing damage to the structure. For cavity and mass wall 

assemblies, the methods and materials in Figures 10 and 11 are recommended.

Figure 9. Recommended wet floodproofing 

techniques for interior wall construction. The 

following flood damage-resistant materials and 

methods will prevent wicking and limit flood 

damage: 1) construct walls with horizontal gaps 

in wallboard; 2) use non-paper-faced gypsum 

wallboard below gap, painted with latex paint; 3) 

use rigid, closed-cell insulation in lower portion 

of walls; 4) use water-resistant flooring with 

waterproof adhesive; and 5) use pressure treated 

wood framing (Source: LSU AgCenter and Coastal 

Contractor Magazine).

Figure 10. Recommended flood-resistant exterior cavity wall construction. The following materials and methods will limit flood damage to 

exterior cavity walls: 1) use brick veneer or fiber-cement siding, with non-paper-faced gypsum sheathing (vinyl siding is also flood-resistant 

but is less resistant to wind damage); 2) provide cavity for drainage; 3) use rigid, closed-cell insulation; 4) use steel or pressure-treated 

wood studs and framing; and 5) use non-paper-faced gypsum wallboard painted with latex paint (Source: Coastal Contractor Magazine and 

Building Science Corporation).

Brick Veneer

Drained Cavity Exterior Rigid

Insulation

Non-paper-faced

Gypsum Sheathing

Non-paper-faced

Gypsum Wallboard

Uninsulated Steel or Pressure-treated

Wood-framed Wall

Membrane or Trowel-on

Vapor Barrier (Class 1)

Membrane or Trowel-on

Vapor Barrier (Class 1)

Latex Paint

Fiber-cement

Siding

1x4 Furing Exterior Rigid 

Insulation

Non-paper-faced

Gypsum Sheathing

Non-paper-faced

Gypsum Wallboard

Latex Paint

Uninsulated Steel or Pressure-treated

Wood-framed Wall
Designing for Flood Levels Above the BFE March 2009 Page 7 of 8

• New and replacement manufactured homes should be installed in accordance with the provisions of the 

2009 edition of the National Fire Protection Association (NFPA) 225, Model Manufactured Home Installation 

Standard (http://www.nfpa.org/aboutthecodes/AboutTheCodes.asp?DocNum=225&cookie_test=1). The 

standard provides flood, wind, and seismic-resistant installation procedures. It also calls for elevating A-zone 

manufactured homes with the bottom of the main chassis frame beam at or above the BFE, not with the top 

of the floor at the BFE.

Other Considerations

As previously stated, in addition to reduced building damage, there are other reasons to design for flood levels 

above the BFE:

• Reduced building maintenance and longer building life 

• Reduced flood insurance premiums 

• Reduced displacement and dislocation of building occupants after floods (and need for temporary shelter 

and assistance) 

• Reduced job loss 

• Increased retention of tax base 

Until flooded, many homeowners and communities don’t think about these benefits. However, one of the most 

persuasive (to homeowners) arguments for elevating homes above the BFE is the reduction in annual flood 

insurance premiums. In most cases, flood premiums can be cut in half by elevating a home 2 feet above the 

BFE, saving several hundred dollars per year in A zones, and $2,000 or more per year in V zones. In V zones, 

savings increase with added freeboard.

A comprehensive study of freeboard (American Institutes for Research, 2006) demonstrated that adding 

freeboard at the time of house construction is cost-effective. Reduced flood damage yields a benefit/cost 

ratio greater than 1 over a wide range of scenarios, and flood insurance premium reductions make adding 

freeboard even more beneficial to the homeowner. Reduced flood insurance premiums will pay for the cost 

of incorporating freeboard in a Zone V house in 1 to 3 years; for a Zone A house, the payback period is 

approximately 6 years.

Figure 11. Recommended flood-resistant exterior 

mass wall construction. The following materials and 

methods will limit flood damage to exterior mass 

walls: 1) use concrete masonry with stucco or brick 

veneer (provide drainage cavity if brick veneer is 

used); 2) use rigid, closed-cell insulation; 3) use 

steel framing; and 4) use non-paper-faced gypsum 

wallboard painted with latex paint (Source: Coastal 

Contractor Magazine and Building Science Corporation).
Designing for Flood Levels Above the BFE March 2009 Page 8 of 8

References

American Institutes for Research. 2006. Evaluation of the National Flood Insurance Program’s Building 

Standards. (available at: http://www.fema.gov/library/viewRecord.do?id=2592) 

ASCE. 2005. Minimum Design Loads for Buildings and Other Structures. ASCE 7-05.

ASCE. 2005. Standard for Flood Resistant Design and Construction. ASCE 24-05.

Building Science Corporation. 2006. (relevant articles and publications available at: http://www.

buildingscience.com).

Coastal Contractor Magazine. July 2006. Low Country Rx: Wet Floodproofing. Drainable, dryable assemblies 

made with water-tolerant materials help speed recovery from deeper than-expected floods, by Ted Cushman. 

(available at: http://www.coastalcontractor.net/cgi-bin/issue.pl?issue=9)

FEMA. 2000. Coastal Construction Manual. FEMA 55. (ordering information at: http://www.fema.gov/pdf/

plan/prevent/nhp/nhp_fema55.pdf)

FEMA. 2005. Home Builder’s Guide to Coastal Construction Fact Sheets Series. FEMA 499. (available at: 

http://www.fema.gov/rebuild/mat/mat_fema499.shtm)

FEMA. 2006. Recommended Residential Construction for the Gulf Coast, Building on Strong and Safe 

Foundations. FEMA 550. (available at: http://www.fema.gov/library/viewRecord.do?id=1853)

FEMA. 2009. Mitigation Assessment Team Report, Hurricane Ike in Texas and Louisiana: Building Performance 

Observations, Recommendations, and Technical Guidance. FEMA P-757. (available at: http://www.fema.gov/

library/viewRecord.do?id=3577)

LSU AgCenter. 1999. Wet Floodproofing. Reducing Damage from Floods. Publication 2771. (available at: 

http://www.lsuagcenter.com/NR/rdonlyres/B2B6CDEC-2BS8-472E-BBD9-OBDEB0B29C4A/26120/

pub2771Wet6.pdf)

NFPA. 2009. Model Manufactured Home Installation Standard. NFPA 225. (available at: http://www.nfpa.org/

aboutthecodes/AboutTheCodes.asp?DocNum=225&cookie_test=1)

Flood Insurance Premium Reductions Can Be Significant

Example 1: V-zone building, supported on piles or piers, 

no below-BFE enclosure or obstruction. $250,000 

building coverage, $100,000 contents coverage. 

Example 2: A-zone building, slab or crawlspace foundation 

(no basement). $200,000 building coverage, $75,000 

contents coverage.

Floor Elevation Above BFE Reduction in Annual Flood 

Premium* Floor Elevation Above BFE Reduction in Annual Flood 

Premium*

1 foot 25% 1 foot 39%

2 feet 50% 2 feet 48%

3 feet 62% 3 feet 48%

4 feet 67% 4 feet 48%

* Compared to flood premium with lowest floor at BFE
HURRICANE IKE RECOVERY ADVISORY

Enclosures and Breakaway Walls January 2009 Page 1 of 4

Purpose: To discuss requirements and 

recommendations for enclosures and breakaway walls 

below the Base Flood Elevation (BFE).

Key Issues

•	Spaces below elevated buildings can be used only for

building access, parking, and storage.

•	Areas enclosed by solid walls below the BFE

(“enclosures”) are subject to strict regulation

under the National Flood Insurance Program (NFIP).

Note that some local jurisdictions enforce stricter 

regulations for enclosures.

•	Enclosures in V-zone buildings must be breakaway

(non-breakaway enclosures are prohibited).

Breakaway enclosures in V zones must be built

with flood-resistant materials, meet specific design

requirements, and be certified by a registered design

professional.

•	Enclosures (breakaway and non-breakaway) in A-zone

buildings must be built with flood-resistant materials

and equipped with flood openings that allow water

levels inside and outside to equalize.

•	Breakaway enclosure walls should be considered

expendable, and the building owner could incur

significant costs when the walls are replaced.

Breakaway wall replacement is not covered by the

flood insurance policy.

•	For V zones, breakaway wall enclosures below an

elevated building will result in higher flood insurance

premiums; however, surrounding below-BFE space

with insect screening, open lattice, slats, or shutters

(louvers) can result in much lower flood insurance 

premiums (Figure 1). Use of these materials will allow

floodwaters to pass into and out of the enclosed

space and minimize damage to the enclosure “walls.”

Although not required by the NFIP, installation of flood

openings in breakaway walls may also reduce damage

to the walls.

Space Below the BFE — What Can It Be Used 

For?

NFIP regulations state that the area below an elevated

building can be used only for parking, building access,

Enclosures and Breakaway

Walls

Figure 1. Wood louvers installed beneath an elevated house in 

a V zone are a good alternative to solid breakaway walls.

WARNING

Designers and owners should realize that:

(1) enclosures and items within them are

likely to be destroyed even during minor flood

events; (2) enclosures, and most items within

them, are not covered by flood insurance and

can result in significant costs to the building

owner; and (3) even the presence of properly

constructed breakaway wall enclosures will 

increase flood insurance premiums for the

entire building (the premium rate will increase

as the enclosed area increases). Including

enclosures in a building design can have

significant cost implications.

The Hurricane Ike Mitigation Assessment

Team (MAT) observed some breakaway

walls in excess of 11’ high. While FEMA

promotes elevating homes above the BFE

(i.e., adding freeboard), one of the unintended

consequences appears to be the increasing

size of floodborne debris elements due to taller

breakaway walls.

http://www.fema.gov
Enclosures and Breakaway Walls January 2009 Page 2 of 4

and storage. These areas must not be finished or used

for recreational or habitable purposes. No mechanical,

electrical, or plumbing equipment is to be installed below

the BFE. 

What is an Enclosure?

An “enclosure” is formed when any space below the BFE

is enclosed on all sides by walls or partitions. Enclosures

can be divided into two types, breakaway and nonbreakaway. 

•	Breakaway enclosures are designed to fail under base

flood conditions without jeopardizing the elevated

building (Figure 2) – any below-BFE enclosure in a V 

zone must be breakaway. Breakaway enclosures are 

permitted in A zones, but must be equipped with flood

openings.

•	Non-breakaway enclosures can be constructed in an A

zone. They may be used to provide structural support

to the elevated building. All A-zone enclosures must be

equipped with flood openings to allow the automatic

entry and exit of floodwaters. This Recovery Advisory 

recommends their use only in A-zone areas subject 

to shallow, slow-moving floodwaters without breaking 

waves. 

Breakaway Walls

Breakaway walls must be designed to break free under

the larger of: 1) the design wind load, 2) the design

seismic load, or 3) 10 pounds per square foot (psf),

acting perpendicular to the plane of the wall (see Figure

3 for an example of a compliant breakaway wall). If

the loading at which the breakaway wall is intended to

collapse exceeds 20 psf, the breakaway wall design 

must be certified. When certification is required, a

registered engineer or architect must certify that the

walls will collapse under a water load associated

with the base	flood and that the elevated portion of

the building and its foundation will not be subject to

collapse, displacement, or lateral movement under

simultaneous wind and water loads. Breakaway walls 

must break away cleanly and must not damage the 

elevated building when they do so (Figure 4). Utilities 

should not be attached to or pass through breakaway 

walls. See FEMA (2008a) Technical Bulletin 9, Design

and Construction Guidance for Breakaway Walls for more 

information. 

Figure 2. Breakaway walls beneath this building failed as 

intended under the flood forces of Hurricane Ike. 

Figure 3. NFIP-compliant breakaway wall construction. 

Figure 4. Building siding extended down and over the breakaway 

wall. Lack of a clean separation allowed damage to spread upward as 

the breakaway wall failed.
Enclosures and Breakaway Walls January 2009 Page 3 of 4

Obstruction Considerations

A V-zone building, elevated on an open foundation without an enclosure or other obstructions below the

BFE, is said to be free of obstructions, and enjoys favorable flood insurance premiums (see FEMA (2008b)

Technical Bulletin 5, Free-of-Obstruction Requirements for more information).

The following building scenarios are also classified by the NFIP as free of obstructions:

•Below BFE space is surrounded by insect screening and/or by wooden or plastic lattice, slats, or shutters

(louvers), if at least 40 percent of the lattice and louver area is open. Lattice can be no thicker than 1⁄2";

slats or louvers can be no thicker than 1".

•	Below BFE space is surrounded by a combination of one solid breakaway wall (or garage door), and all other

sides of the enclosure are insect screening, or wooden or plastic lattice, slats, or louvers.

The following building scenarios are classified by the NFIP as with obstructions:

•	Below BFE space is fully enclosed by solid breakaway walls.

•	Below BFE space is enclosed by a combination of two or more solid breakaway walls, with the remaining

sides of insect screening, or wooden or plastic lattice, slats, or louvers.

Flood Openings

Foundation walls and other enclosure walls of A-zone

buildings (including Coastal A-zone buildings) must be

equipped with openings that allow the automatic entry 

and exit of floodwaters (Figure 5).

A-zone opening requirements are as follows:

•	Flood openings must be provided in at least two of the 

walls forming the enclosure.

•	The bottom of each flood opening must be no more 

than 1’ above the higher of the interior or exterior 

adjacent grade.

•	Louvers, screens, or covers may be installed over 

flood openings as long as they do not interfere with the

operation of the openings during a flood.

•	Flood openings may be sized according to either a

prescriptive method (1 square inch of flood opening per square foot of enclosed area) or an engineering

method (which must be certified by a registered engineer or architect).

Details concerning flood openings can be found in FEMA (2008c) Technical Bulletin 1, Openings in Foundation 

Walls and Walls of Enclosures. 

Other Considerations

Enclosures are strictly regulated because, if not constructed properly, they can transfer flood forces to the

main structure (possibly leading to structural collapse). There are other considerations as well:

•	Owners may be tempted to convert enclosed areas below the BFE into habitable space, leading to life-safety

concerns and uninsured losses. Construction without enclosures should be encouraged. Contractors should 

not stub out utilities in enclosures (utility stub-outs make it easier for owners to finish and occupy the

space).

•	Siding used on the elevated portions of a building should not extend down over breakaway walls. Instead,

a clean separation should be provided so that any siding installed on breakaway walls is structurally

independent of siding elsewhere on the building. Without such a separation, the failure of breakaway walls

can result in damage to siding elsewhere on the building (see Figure 4).

•	Solid breakaway wall enclosures in V zones will result in significantly higher flood insurance premiums

(especially where the enclosed area is 300 square feet or greater). Insect screening or lattice, slats, or

louvers are recommended instead. 

Figure 5. Flood opening in a below-BFE enclosure wall. 
Enclosures and Breakaway Walls January 2009 Page 4 of 4

•	If enclosures are constructed in Coastal A zones (see the Hurricane Ike Recovery Advisory, Design and 

Construction in Coastal A Zones), open foundations with breakaway enclosures are recommended in lieu 

of foundation walls or crawlspaces. If solid breakaway

walls are used, they must be equipped with flood

openings that allow floodwaters to enter and exit the

enclosure. Use of breakaway enclosures in Coastal

A zones (or any A zone) will not lead to higher flood

insurance premiums.

•	Garage doors installed in below-BFE enclosures

of V-zone buildings – even reinforced and highwind-resistant doors – must meet the performance

requirement discussed in the Breakaway Walls section 

of this Recovery Advisory. Specifically, the doors must

be designed to break free under the larger of the

design wind load, the design seismic load, or 10 psf,

acting perpendicular to the plane of the door. If the

loading at which the door is intended to collapse is

greater than 20 psf, the door must be designed and 

certified to collapse under base flood conditions. 

See the Breakaway Walls section for information about certification requirements.

References

FEMA. 2008a. Design and Construction Requirements for Breakaway Walls. Technical Bulletin 9, available at:

http://www.fema.gov/library/viewRecord.do?id=1722.

FEMA. 2008b. Free-of-Obstruction Requirements. Technical Bulletin 5, available at: http://www.fema.gov/

library/viewRecord.do?id=1718.

FEMA. 2008c. Openings in Foundation Walls and Walls of Enclosures. Technical Bulletin 1, available at:

http://www.fema.gov/library/viewRecord.do?id=1579.

FEMA. 2009. Hurricane Ike Recovery Advisory, Design and Construction in Coastal A Zones.

This Recovery Advisory recommends the use of

insect screening, or open wood or plastic lattice,

slats, or louvers, instead of solid breakaway

walls beneath elevated residential buildings.

This Recovery Advisory recommends that flood

openings be considered for solid breakaway

walls in V zones, even though they are not

required by the NFIP. The presence of flood

openings may relieve flood forces against the

solid breakaway walls and reduce damage to the

walls.
HURRICANE IKE RECOVERY ADVISORY

Erosion, Scour, and Foundation Design January 2009 Page 1 of 8

Purpose: To discuss how any lowering of the ground surface can affect the ability of a building foundation to 

resist design loads, and to provide additional guidance for coastal foundation design.

Key Issues

•	Coastal buildings are often subject to flood loads

and conditions that do not affect inland buildings. 

These include waves, high velocity storm surge 

flow, floodborne debris, and erosion and scour. This 

Recovery Advisory will focus on erosion and scour. 

See FEMA 499, Home Builder’s Guide to Coastal 

Construction (2005), Fact Sheets 11 through 15 at: 

http://www.fema.gov/library/viewRecord.do?id=1570, and FEMA 55, Coastal Construction Manual (2000) 

at: http://www.fema.gov/library/viewRecord.do?id=1671 for discussion of other foundation issues.

•	Foundations must transfer all loads imposed on the building into the ground. If the foundation is not strong

enough or deep enough to do this, the building will be destroyed. If the foundation embedment into the

ground is not sufficient to account for erosion and scour that may occur over the life of the building, the 

building is vulnerable to collapse under design flood and wind conditions.

•	Predicting the incidence, location, and magnitude of coastal erosion and scour is difficult, and present-day

building codes and standards do not prescribe clear-cut solutions for designers. Therefore, designers should

be conservative with their foundation designs. This means foundations may need to be stronger, deeper, and 

higher than what has historically been used. Lessons learned from Hurricane Ike and other recent coastal

storm events should be incorporated into foundation designs. 

Erosion and Scour Basics

Erosion is defined by the International Building Code®(ICC, 2006) as the “wearing away of the ground surface

as a result of the movement of wind, water or ice.” Section 7.5 of FEMA’s Coastal Construction Manual

describes erosion as “the wearing or washing away of coastal lands.” Since the exact configuration of the soil

loss is important for foundation design purposes, a more specific definition is used in this Recovery Advisory 

(see text box and Figure 1).

Erosion, Scour, and 

Foundation Design

Erosion refers to a general lowering of the 

ground surface over a wide area.

Scour refers to a localized loss of soil, often 

around a foundation element.

Figure 1. Distinguishing between coastal erosion and scour. A building may be subject to either or both, depending on the building location, 

soil characteristics, and flood conditions. 

http://www.fema.gov
Erosion, Scour, and Foundation Design January 2009 Page 2 of 8

Erosion can occur across a wide range of timeframes 

– it can be gradual, occurring over a long period of time 

(many years); more rapid, occurring over a relatively short 

period of time (weeks or months); or episodic, occurring

during a single coastal storm event over a short period of 

time (hours or days). Figure 2 shows the result of erosion 

occurring over a long timeframe – buildings that were 

formerly on upland property, but now stand on the active 

beach. Figure 3 shows episodic erosion that occurred 

during Hurricane Ike. In both cases, the recession of the

shoreline resulted in a horizontal translation of the beach 

profile and a lowering of the ground elevation under and 

near the affected buildings. The closer a building is to 

the shoreline, the more likely erosion will occur and the

greater the erosion depth will be.

Scour occurs when floodwater passes around

obstructions in the water column. As the water 

flows around an object, it must change direction and

accelerate. Soil can be loosened and suspended by this 

process or by waves striking the object, and be carried

away. Pilings, pile caps, columns, walls, footings, slabs,

and other objects found under a coastal building can lead

to localized scour. Scour effects increase with increasing 

flow velocity and turbulence, and with increasing soil

erodibility.

Scour effects are generally localized, ranging from small, 

shallow conical depressions in the sand around individual 

piles (Figure 4) to larger and deeper depressions around 

individual piles (Figure 5), to a building-sized shallow

depression around a group of piles (Figure 6), to a large 

and deep depression around a building foundation 

(Figure 7). Scour depressions like that shown in Figure

7 were observed frequently following Hurricane Ike,

and many of these reportedly were 6 to 10' deep and 

required hundreds of cubic yards of soil to fill. The 

presence of large, non-frangible concrete slabs and deep

grade beams under the buildings may be a contributing 

factor to the large local scour depressions observed.

In some cases, buildings may settle due to inadequate

pile embedment, coupled with some combination of 

erosion, scour, and soil liquefaction that leads to loss of 

bearing. This type of failure was observed by the Huricane 

Ike FEMA Mitigation Assessment Team (MAT) at Surfside

Beach, TX (Figure 8) and Holly Beach, LA.

Figure 2. Long-term erosion has caused the shoreline to 

retreat and has left homes standing on the beach (Surfside 

Beach, TX). July 2007 Texas General Land Office photo. 

Figure 3. Storm-induced erosion beneath an elevated coastal 

building (Galveston Island, TX, Hurricane Ike). 

Figure 4. Local scour around foundation piles (Pensacola 

Beach, FL, Hurricane Ivan). 

Figure 5. Local scour around foundation piles (Holly Beach, 

LA, Hurricane Ike). 
Erosion, Scour, and Foundation Design January 2009 Page 3 of 8

There is one other erosion and scour scenario to consider in foundation design – the loss of soil around 

or under a building as a result of storm surge flow being channeled or directed across a building site. This

process usually takes place where storm surge flow is constrained between large buildings or gaps in shore

protection, or when return flow to the sea follows paths of least resistance, such as along canals and roads

(Figure 9). 

Erosion and Scour – Impacts on Foundations

Erosion and scour have several adverse impacts on coastal foundations:

•	Erosion and scour reduce the embedment of the foundation into the soil, causing shallow foundations to

collapse and making buildings on deep foundations more susceptible to settlement, lateral movement, or

overturning from lateral loads. 

•	Erosion and scour increase the unbraced length of pile foundations, increase the bending moment to which

they are subjected, and can overstress piles.

•	Erosion over a large area between a foundation and a flood source exposes the foundation to increased

lateral flood loads (i.e., greater stillwater depths, possible higher wave heights, and higher flow velocities).

•	Local scour around individual piles or a building foundation will not generally expose foundations to greater

flood loads, but linear scour across a building site may do so.

Figure 6. Local scour around a 3rd row house’s pile foundation 

(Bolivar Peninsula, TX, Hurricane Ike). 

Figure 7. Extreme local scour around a Gulf-front pile 

foundation (Bolivar Peninsula, TX, Hurricane Ike). 

Figure 8. Differential settlement of buildings thought to be 

a result of inadequate foundation embedment coupled with 

erosion, scour, and/or soil liquefaction (Surfside Beach, TX, 

Hurricane Ike). 

Figure 9. Linear scour and erosion patterns aligning with 

canals and roads (Bolivar Peninsula, TX, Hurricane Ike). 
Erosion, Scour, and Foundation Design January 2009 Page 4 of 8

To illustrate these points, calculations were made to examine the effects of erosion and scour on foundation

design for a simple case – a 32' x 32', two-story house (10' story height), situated away from the shoreline

and elevated 8' above grade on 25 square timber piles (spaced 8' apart), on medium dense sand. The house

was subjected to a design wind event with a 130-mph (3-second gust) wind speed and a 4' stillwater depth

above the uneroded grade, with storm surge and broken waves passing under the elevated building. Lateral

wind and flood loads were calculated in accordance with ASCE/SEI 7-05 Minimum Design Loads for Buildings 

and Other Structures (model codes and related prescriptive standards, such as the International Building

Code (IBC), the International Residential Code®(IRC®), and ICC-600 Standard for Residential Construction in 

High Wind Areas, are based on ASCE 7 loads). For this illustration, the piles were analyzed under lateral wind

and flood loads only; dead, live and wind uplift loads were neglected. If these neglected loads are included in

the analysis, deeper pile embedment and possibly larger piles may be needed.

Three different timber pile sizes (8" square, 10" square, and 12" square) were evaluated using pre-storm

embedment depths of 10', 15', and 20', and five different erosion and scour conditions (Erosion = 0' or 1'; 

Scour ranges from 2.0 times the pile diameter to 4.0 times the pile diameter). The results of the analysis are 

shown in Table 1. A shaded cell indicates the combination of pile size, pre-storm embedment, and erosion/

scour does not provide the bending resistance and/or embedment required to resist lateral loads. The 

reason(s) for a foundation failure is indicated in each shaded cell, using “P” for failure due to bending and

overstress within the pile and “E” for an embedment failure from the pile/soil interaction. An unshaded cell

with “OK” indicates bending and foundation embedment criteria are both satisfied by the particular pile size/

pile embedment/erosion-scour combination.

Table 1. Example foundation adequacy calculations for a two-story house supported on square timber piles and situated away from 

the shoreline, storm surge and broken waves passing under the building, 130-mph wind zone, soil = medium dense sand. Shaded cells 

indicate the foundation fails to meet bending (P) and/or embedment (E) requirements.

Pile Embedment

Before Erosion and Scour Erosion and Scour Conditions

Pile Diameter, a

8 inch 10 inch 12 inch

10 feet

Erosion = 0, Scour = 0 P, E E OK

Erosion = 1 foot, Scour = 2.0 a P, E E E

Erosion = 1 foot, Scour = 2.5 a P, E E E

Erosion = 1 foot, Scour = 3.0 a P, E E E

Erosion = 1 foot, Scour = 4.0 a P, E P, E E

15 feet

Erosion = 0, Scour = 0 P OK OK

Erosion = 1 foot, Scour = 2.0 a P OK OK

Erosion = 1 foot, Scour = 2.5 a P OK OK

Erosion = 1 foot, Scour = 3.0 a P OK OK

Erosion = 1 foot, Scour = 4.0 a P, E P, E E

20 feet

Erosion = 0, Scour = 0 P OK OK

Erosion = 1 foot, Scour = 2.0 a P OK OK

Erosion = 1 foot, Scour = 2.5 a P OK OK

Erosion = 1 foot, Scour = 3.0 a P OK OK

Erosion = 1 foot, Scour = 4.0 a P P OK

Resisting higher bending moments brought about by erosion and scour may necessitate a larger pile crosssection or decreased pile spacing (i.e., more piles) or, in some cases, use of a different pile material (e.g., 

concrete or steel instead of wood). Resisting increased lateral flood loads brought about by erosion (and

possibly by linear scour) would necessitate a similar approach. However, designers must remember that 

increasing the number of piles or increasing the pile diameter will, in turn, also increase lateral flood loads

on the foundation. 

Resisting increased unbraced lengths brought about by erosion and scour will require additional 

embedment of the foundation into the ground.
Erosion, Scour, and Foundation Design January 2009 Page 5 of 8

Review of the table shows several key points:

•	Increasing pile embedment will not offset foundation

inadequacy (bending failure) resulting from too small 

a pile cross-section or too weak a pile material.

•	Increasing pile cross-section (or material strength) will

not compensate for inadequate pile embedment

•	Given the building and foundation configuration used

in the example, the 8" square pile is not strong

enough to resist the lateral loads resulting from the 

130-mph design wind speed under any of the erosion

and scour conditions evaluated, even if there is no 

erosion or scour. Homes supported by 8" square

timber piles, with embedment depths of 10' or less, 

will likely fail in large numbers when subjected to

design or near-design loads and conditions. Homes

supported by deeper 8" piles may still be lost during

a design event due to pile (bending) failures

•	The 10" square pile is strong enough to resist bending under all but the most severe erosion and scour

conditions analyzed. 

•	The 12" pile is the only pile size evaluated that satisfies bending requirements under all erosion and scour

conditions analyzed. The 12" pile works with 10' of embedment under the no erosion and scour condition.

However, introducing as little as 1' of erosion, and scour equal to twice the pile diameter, was enough to 

render the foundation too shallow.

•	15' of pile embedment is adequate for both 10" and 12" piles subject to 1' of erosion and scour up

to three times the pile diameter. However, when the scour is increased to four times the pile diameter 

(frequently observed following Hurricane Ike), 15' of embedment is inadequate for both piles. In general

terms, approximately 11' of embedment is required in this example house to resist the loads and conditions

after erosion and scour are imposed.

•	The 12" pile with 20' of embedment was the only foundation that worked under all erosion and scour

conditions analyzed. This pile design may be justified for the sample house analyzed when expected erosion

and scour conditions are unknown or uncertain.

NFIP and Building Code Requirements

One of the requirements of Section 60.3(a)(3) of the NFIP regulations that applies to all flood hazard zones

(V, VE, V1-30, A, AE, A1-30, AO, AH, etc.) within the Special Flood Hazard Area (SFHA) is:

“If a proposed building site is in a flood-prone area, all new construction and substantial improvements

shall be designed (or modified) and adequately anchored to prevent flotation, collapse, or lateral

movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of 

buoyancy.” 

A requirement in Section 60.3(e)(4) states that all new construction and substantial improvements in V 

zones must be elevated on pilings and columns so that:

“(i) the bottom of the lowest horizontal structural member of the lowest floor (excluding the pilings or

columns) is elevated to or above the base flood level; and

(ii) the pile or column foundation and structure attached thereto is anchored to resist flotation, collapse 

and lateral movement due to the effects of wind and water loads acting simultaneously on all building 

components. 

Water loading values used shall be those associated with the base flood. Wind loading values used shall

be those required by applicable State or local building standards. A registered professional engineer or 

architect shall develop or review the structural design, specifications and plans for the construction, and 

shall certify that the design and methods of construction to be used are in accordance with accepted 

standards of practice for meeting the provisions of paragraphs (e)(4)(i) and (ii) of this section.” 

WARNING

The results in Table 1 should not be used in 

lieu of building- and site-specific engineering 

analyses and foundation design. The table 

is for illustrative purposes only and is based 

upon certain assumptions and simplifications, 

and for the combinations of building 

characteristics, soil conditions, and wind and 

flood conditions described above. Registered 

design professionals should be consulted for 

foundations designs.
Erosion, Scour, and Foundation Design January 2009 Page 6 of 8

The International Residential Code (2006) has similar requirements:

“R324.1.1 [Flood Resistant Construction] Structural systems. All structural systems of all buildings and 

structures shall be designed, connected and anchored to resist flotation, collapse or permanent lateral

movement due to structural loads and stresses from flooding equal to the design flood elevation.

R324.3.3 [Coastal high-hazard areas] Foundations. All buildings and structures erected in coastal highhazard areas shall be supported on pilings or columns and shall be adequately anchored to such pilings 

or columns. Pilings shall have adequate soil penetration to resist the combined wave and wind loads

(lateral and uplift). Water loading values used shall be those associated with the design flood. Wind

loading values used shall be those required by this code. Pile embedment shall include consideration of

decreased resistance capacity caused by scour of soil strata surrounding the piling. Pile systems design

and installation shall be certified in accordance with Section R324.3.6. Mat, raft or other foundations that 

support columns shall not be permitted where soils investigations that are required in accordance with 

Section R401.4 indicate that soil material under the mat, raft or other foundation is subject to scour or

erosion from wave-velocity flow conditions.

Buildings and structures, and all parts thereof, shall be constructed to support safely all loads, including

dead loads, live loads, roof loads, flood loads, snow loads, wind loads and seismic loads as prescribed in

this code. The construction of buildings and structures shall result in a system that provides a complete 

load path capable of transferring all loads from their point of origin through the load-resisting elements of

the foundation.”

Thus, designers are responsible for ensuring that a foundation for a building in any flood hazard area must

be adequate to support a building under applicable design loads and load combinations. Designers must

consider the effects of erosion and scour when foundations are designed. Designers must certify the

foundations.

There may also be other (State or local) foundation design and certification requirements. 

Erosion and Scour Design Guidance

Given that the design requirements listed above are performance requirements, designers must translate

those into practice. This can be difficult with respect to estimating erosion and scour conditions at a particular 

site, since definitive guidance for estimating coastal erosion and scour is not present in building codes and 

standards.

FEMA’s Coastal Construction Manual (FEMA, 2000) provides some information and guidance, but even 

this should be considered preliminary and subject to improvement as we learn more from post-storm

investigations. The pertinent CCM sections and guidance are summarized below:

CCM Section 7.5: this section summarizes the causes of erosion, its impacts on coastal lands and 

buildings, and how it is measured. Section 7.5.2.5 discusses local scour. One key point is a procedure

outlined in the note on page 7-28 and illustrated in CCM Figure 7-66 – three steps that a designer should

use to estimate future ground elevations and flood conditions at a site:

Step 1: determine the most landward shoreline location expected during the life of the building

Step 2: define the lowest expected ground

elevation during the life of the building

Step 3: define the highest expected BFE during

the life of the building 

CCM Section 7.8.1.4 discusses FEMA’s current

procedures for estimating storm-induced erosion.

CCM Section 7.9.2 discusses how designers can update an obsolete flood hazard description for a site

by accounting for long-term (Step 1 above) and storm-induced erosion (Step 2 above). CCM Figure 7-

67 (Figure 10) provides an example, illustrating the use of published long-term erosion information and

simple storm erosion calculations to estimate future ground elevations at a building site.

CCM Section 11.6.11 discusses local scour and presents a simple method for calculating erosion around 

a single pile. The method predicts the depth of a scour depression below the eroded ground elevation 

Designers in Texas and Louisiana can obtain

erosion data and other related information from 

various state agencies (see References).
Erosion, Scour, and Foundation Design January 2009 Page 7 of 8

is equal to 2.0 times the pile diameter, unless 

non-erodible soil lies beneath the ground surface

(Figure 11). 

Designers should use the CCM scour depth

relationship (Smax = 2.0 a) with caution. 

Observations after Hurricane Ike showed scour

exceeded twice the pile diameter at many locations.

This could have been due to deeper scour depths 

around entire pile foundations (Figures 6 and 7), 

or to the presence of concrete slabs and deep 

grade beams that channeled flow between the

bottom of the slab and the soil, or to other factors. 

Given the uncertainty over the exact cause of local

scour during Hurricane Ike, foundation designs for

reconstruction along the Gulf shoreline should be

very conservative, and an assumed scour depth 

of 6 to 8' would not be unreasonable. Designers

should investigate local soils and Hurricane Ikeinduced scour at nearby locations before selecting 

a scour depth. Post-hurricane aerial photographs,

such as those obtained after Hurricane Ike by NOAA

and USGS (see References) will provide a good

source of data for designers. 

The CCM mentions linear scour channels occurring 

between large buildings or in-line with roads,

canals, and drainage features (see CCM Section 

8.3.2), but does not provide design guidance for

estimating linear scour depths. As was the case 

with local scour, designers should utilize posthurricane data when they estimate linear scour 

likelihood and depth.

Existing Homes: Are the Pile Foundations 

Adequate?

The owner of an existing home may wonder whether

the pile foundation is adequate to withstand erosion and scour during a design event. The builder or building 

official may have permit records, building plans, or foundation design information for the house, or may be 

able to provide information about typical design requirements, construction practices, and probable pile 

embedment depths for houses of the same age. A licensed engineer can perform an inspection of the 

foundation, provide information about non-destructive testing methods to determine pile embedment depth,

review available foundation data, and analyze the foundation. 

References

ASCE. 2005. Minimum Design Loads for Buildings and Other Structures. ASCE/SEI 7-05.

FEMA. 2000. Coastal Construction Manual, 3rd ed. FEMA 55. 

FEMA. 2005. Home Builder’s Guide to Coastal Construction. FEMA 499. See http://www.fema.gov/library/

viewRecord.do?id=1570 

ICC 2006. International Building Code.

ICC 2006. International Residential Code with 2007 Supplement.

ICC 2008. Standard for Residential Construction in High Wind Areas. ICC 600.

Louisiana Department of Natural Resources. 2008. Coastal Restoration and Management data and reports.

See http://dnr.louisiana.gov/crm/

Figure 10. CCM Figure 7-67 illustrating a simple procedure to 

account for long-term erosion and storm erosion.

Figure 11. CCM Figure 11-12 illustrating scour estimate 

around a single pile – Hurricane Ike showed this method may 

underestimate local scour.

Eroded Ground

Surface
Erosion, Scour, and Foundation Design January 2009 Page 8 of 8

NOAA. 2008. Post-Ike aerial photographs. See http://ngs.woc.noaa.gov/ike/index.html

Texas Bureau of Economic Geology. 2008. Coastal Studies Program data and reports. See http://www.beg.

utexas.edu/coastal/coastal01.htm

USGS. 2008. Post-Ike aerial photographs and data. See http://coastal.er.usgs.gov/hurricanes/ike/
HURRICANE IKE RECOVERY ADVISORY

Minimizing Water Intrusion Through Roof Vents in High-Wind Regions April 2009 Page 1 of 7

Purpose: To recommend practices for minimizing water intrusion through roof vent systems that can lead to 

interior damage and mold growth in high-wind regions (i.e., greater than 90-miles per hour [mph] gust design 

wind speed).

Key Issues

•	Hurricane winds can drive large amounts of water through attic ventilation openings. The accumulating water

soaks insulation, which can lead to mold growth and, in some cases, to the collapse of ceilings. 

•	Attic ventilation can be provided by a number of devices, most of which have been observed to allow water

intrusion under certain conditions and some of which have been observed to blow off. These devices

include:

•	Soffit vents

•	Ridge vents

•	Gable end vents

•	Off-ridge vents

•	Gable rake vents

•	Turbines

•	Adequate ventilation of attics is generally required to

promote the health of wood structural members and

sheathing in the attic.

•	Attic ventilation can reduce the temperatures of roof

coverings, which will typically prolong the life of the 

roof covering. However, roof color can have more of an

impact on roof covering temperature than the amount 

of ventilation that is or is not provided.

•	An unventilated attic can be an effective way to

prevent water intrusion and this type of attic is 

gaining popularity for energy efficiency reasons,

provided the air conditioning system is sized 

appropriately. However, an unventilated attic is best

accomplished when it is specifically designed into the

house and all of the appropriate details are handled 

properly. On an existing house, any attempt to change

to an unventilated attic configuration needs to be

done very carefully with the advice of knowledgeable experts. There are a number of changes that have to

be made to produce a successful transition from a ventilated to an unventilated attic. One side effect of

going to an unventilated attic may be to void the warranty for the roof covering.

•	The following information is intended to help minimize water intrusion through new and existing attic

ventilation systems, not to change from a ventilated to an unventilated system. With the exception of

the plugging of gable rake vents, all other shuttering of openings or plugging of vents should be done

on a temporary basis and removed once the storm threat is over so that the attic is once again properly

ventilated.

Minimizing Water Intrusion Through 

Roof Vents in High-Wind 

Regions http://www.fema.gov

The Unventilated Attic

The most conservative approach to preventing 

wind-driven rain from entering the attic is to 

eliminate attic ventilation, but unventilated

attics are controversial. Although allowed by the

International Residential Code®(IRC®), provided 

the Code’s criteria are met, unventilated attics

may not comply with local building codes.

However, when unventilated attics are allowed

by the building code or code compliance is

not an issue, and when climatic and interior 

humidity conditions (e.g., no indoor swimming 

pools) are conducive to an unventilated design, 

an unventilated attic is a reliable way to prevent

wind-driven rain from entering the attic.

Air barrier: Refer to the Siding Installation in 

High-Wind Regions, Hurricane Ike Recovery

Advisory for recommendations regarding attic air

barriers.
Minimizing Water Intrusion Through Roof Vents in High-Wind Regions April 2009 Page 2 of 7

Checking Soffit Material Installation

As noted above, the most critical soffit installations to

check are those where vinyl or aluminum soffit panels

are used. Soffits should be fastened to the eave

structure; they should not be loose in the channels.

Pushing up on the soffit material and the channels used

to support the material can be revealing. If it moves

Mitigation Guidance

Soffit Vents

Key Issues

•	First and foremost, it is important to keep the soffit

material in place. While some water can be blown

into the attic through almost any type of soffit vent,

the amount of water intrusion increases dramatically 

when the soffit material is missing (Figure 1).

•	Plywood or wood soffits are generally adequately

anchored to wood framing attached to the roof 

structure and/or the walls. However, it has been

common practice for vinyl and aluminum soffit panels

to be installed in tracks that are frequently very poorly

connected to the walls and fascia at the edge of the 

roof overhang. When these poorly anchored soffits

are blown off, water intrusion increases significantly.

Properly installed vinyl and aluminum soffit panels are

fastened to the building structure or to nailing strips

placed at intervals specified by the manufacturer.

Proper Installation

The details of proper installation of vinyl and aluminum soffits depend on the type of eave to which they are

attached. The key elements are illustrated in Figure 2.

A. Roof truss or rafter framing should extend across

the bottom of the eaves, or be added to create a

structural support for the soffit. As an alternative,

soffits can be attached directly to the undersides of

the angled rafters.

B. Nailing strips should be provided, if necessary,

to allow attachment of the soffit at the ends.

Intermediate nailing strips may be needed, depending

on the maximum span permitted for the soffit. If this

is not known, the span between attachment points

should not exceed 12" in high-wind regions.

C. A J-channel (illustrated), F-channel, or other receiver

as specified by the manufacturer should cover the

ends of the soffit panels. Fasteners should be those

specified by the manufacturer. Fasteners should be

used through the nailing strip of each panel and at 

any other points (such as in the “valleys” of the soffit) if

specified.

D. The overall span (eave depth) of the soffit should not exceed any limits specified by the

manufacturer, and any required intermediate attachment points should be used.

Figure 1. Missing soffit material.

Figure 2. Key soffit installation points.

B

A

C

D

Soffits can receive positive and negative

(suction) loads; therefore, soffits need to be

designed and installed to resist loads that push 

up and pull down on the soffit.
Minimizing Water Intrusion Through Roof Vents in High-Wind Regions April 2009 Page 3 of 7

readily or is easy to deform, it probably is not attached

very well. Similarly, if the width of the overhang is

greater than 12", there should be an intermediate

support running along the middle of the soffit and the

panels should be attached to this support in addition

to the supports at the ends of the panels. If you are 

concerned about the installation but can’t be sure,

there are a couple of tools with a viewing screen 

connected to a small camera lens and light mounted at 

the end of a flexible tube that can be used to observe

the connections. These devices allow inspection 

through a small hole that is drilled in an inconspicuous 

location that can be later filled with sealant. In order to

ensure that you have a strong connection at the wall, 

there should be wood blocking running along the wall

above the track where the soffit channel is attached and

the channel should be fastened to that blocking. If you

do not find wood blocking and either see no vertical

nailing surface on the channel or see occasional tabs

that have been cut and bent up to allow fastening to

the wall, strengthening of the anchorage of the soffit

material is clearly indicated.

Remedial Measures

If the inspection indicates a poorly attached soffit, the

best way to ensure that the soffit material is adequately

anchored in place is to remove it and install adequate

wood blocking to allow solid anchorage of the soffit

material. In some cases, it may be possible to remove

the soffit material and reinstall it. However, it is also

likely that some or all of the material will need to 

be replaced, so make sure that it can be matched

before it is removed. Short of removing and properly

reinstalling the soffit material, testing has shown that

the anchorage can be greatly improved by applying

a bead of sealant (Figure 3) along the bottom edge

of the wall channel to adhere it to the wall surface 

below followed by applying large dabs of sealant in

indentations between the soffit panels and the wall

channel at one end (Figure 4) and the fascia flashing

at the other end. Surfaces receiving sealant should be

cleaned in order to facilitate bonding. Extra resistance

can be gained by installing screws that mechanically

tie the soffit panels to both the fascia flashing and to

the wall channel (Figure 5). Note that use of sealant 

is a remedial measure only and is not a substitute for

proper installation and fastening of soffits in a new

installation.

Wind-driven rain penetration: Currently there is no

adequate standard test method to evaluate the

potential for wind-driven rain to enter attics through 

soffit vent openings, such as those shown in Figure

6. To avoid water entry at soffit vents, options include

eliminating soffit vents and providing an alternate

method for air to enter the attic, or design for an 

unventilated attic. Another approach is to place filter

fabric (like that used for heating, ventilation, or cooling

Figure 3. Applying a bead of sealant. (Note: Black sealant 

was used so that it would be visible in the photograph. 

Normally a matching sealant color would be used.)

Rain screen wall venting: In lieu of providing

soffit vents, another method to provide attic

air intake is through a pressure-equalized rain

screen wall system as discussed in Siding 

Installation in High-Wind Regions, Hurricane Ike

Recovery Advisory. This alternative approach

eliminates soffit vents and their susceptibility to

wind-driven rain entry.

Figure 4. Applying dabs of sealant.

Figure 5. Screws through wall channel.
Minimizing Water Intrusion Through Roof Vents in High-Wind Regions April 2009 Page 4 of 7

[HVAC] system filters) above the vent openings; however, such an

approach needs to be custom designed.

Fascia cover: Field investigations after Hurricane Ike showed many

cases where the aluminum fascia cover (fascia cap) from the fascia 

board was blown off (Figure 7). The fascia cover normally covers the

ends of vinyl and aluminum soffits. When the fascia cover is blown off,

the ends of the soffit panels are exposed to wind and wind-driven rain.

The IRC currently has no guidelines for the installation of fascia

covers. Aluminum fascia covers are typically tucked under the roof

drip edge and face-nailed every few feet. More frequent nailing would

help secure the fascia cover, but would also inhibit normal thermal

movement, which can cause unattractive warping and dimpling of 

the cover. Vinyl fascia covers are available, which are attached to a

continuous strip of utility trim placed underneath the drip edge. This 

provides a somewhat more secure, continuous attachment and allows 

for thermal movement. Aluminum fascia covers can also be fieldnotched and installed with utility trim.

Ridge Vents

Key Issues

• Ridge vents are frequently fastened down

using ordinary roofing nails since these are

normally handy. It is pretty common to find

ridge vents dislodged or blown off during a

hurricane (Figure 8). Even a partially dislodged

ridge vent can begin to act like a scoop that

collects wind-driven rain and directs it into the 

attic.

• Most roofing manufacturers now make ridge

vents that have passed wind-driven water 

tests. They are identified as having passed

Florida Building Code’s Product Approvals or

Testing Application Standard (TAS) 100(A).

Typically, they include a baffle in front of the

vent tubes that provide the passageway for hot

attic gasses to escape. This baffle is intended

to trip any flow of wind and water blowing up

the surface of the roof and deflect it over the 

top of the roof ridge.

Figure 8. This metal ridge vent was attached 

with widely spaced roofing nails.

Figure 6. Fiber cement soffit with ventilation 

slots (red arrow). 

Figure 7. Loss of fascia cover exposes ends of vinyl soffit to 

direct entry of wind-driven rain.

Slotting the Deck

When ridge venting is being added to a roof that previously

did not have it, it is necessary to cut a slot through the 

decking. When doing so, it is important to set the depth 

of the saw blade so that it only slightly projects below the

bottom of the decking. At the residence shown in Figure 8,

the saw blade cut approximately 11⁄2” into the trusses and

cut a portion of the truss plate (red arrow).
Minimizing Water Intrusion Through Roof Vents in High-Wind Regions April 2009 Page 5 of 7

Checking Ridge Vents and Their Installation

When they are used, ridge vents are the last part of the roof to be installed. Consequently, the connection is

readily accessible and frequently visible without having to pry up the edge of the vent cover top. Check the

type and condition of the fasteners. If the fasteners are nails, replacement of the fasteners is in order. If 

the vent has clear holes or slots without any baffle or trip next to the edge of the vent channels, the vent is

probably not one that is resistant to water intrusion and you should consider replacing the ridge vent with one

that has passed the wind-driven water intrusion tests.

Remedial Measures

Replace nails with gasketed stainless steel wood

screws that are slightly larger than the existing nails

and, if possible, try to add fasteners at locations where

they will be embedded in the roof structure below

and not just into the roof sheathing. Close spacing of

fasteners is recommended (e.g., in the range of 3 to 6"

on center, commensurate with the design wind loads). 

If the ridge vents are damaged or are one of the older 

types that are not resistant to water intrusion, they 

should be replaced with vents that have passed the

wind-driven water intrusion tests.

Gable End Vents

Key Issues

•	Virtually all gable end vents (Figure 9) will leak when

the wall they are mounted on faces into the winddriven rain. The pressures developed between the

outside surface of the wall and the inside of the 

attic are sufficient to drive water uphill for a number

of inches and, if there is much wind flow through 

the vent, water carried by the wind will be blown

considerable distances into the attic.

Remedial Measures

If it is practical and possible to shutter gable end vents

from the outside of the house, this is the preferable

way to minimize water intrusion through gable end

vents (Figure 10). Install permanent anchors in the

wood structure around the gable vent and precut,

pre-drill, and label plywood or other suitable shutter

materials so that they are ready for installation by a

qualified person just before a storm approaches. If

installation of shutters from the outside is difficult

because of the height or other considerations, but there

is access through the attic, the gable vent opening can

be shuttered from the inside. However, careful attention

needs to be paid to sealing around the shutter and

making sure that any water that accumulates in the 

cavity can drain to the outside of the house and not 

into the wall below.

Off-ridge Vents

Key Issues

•	Poorly anchored off-ridge vents can flip up and

become scoops that direct large amounts of winddriven rain into the attic (Figure 11).

Figure 10. Shuttered gable end vent.

Figure 9. Gable end vent.

Figure 11. Two off-ridge vents are shown in this photograph. 

The vent that is covered with roofing felt flipped up and 

allowed a substantial amount of water to enter the residence. 

Carpeting, kitchen cabinets, and a large amount of gypsum 

board had to be replaced because of the water intrusion.
Minimizing Water Intrusion Through Roof Vents in High-Wind Regions April 2009 Page 6 of 7

•	Some vents are also prone to leaking when winds blow from certain directions. This will depend on the

location of the vent on the roof surface and the geometry of the roof, as well as the geometry of the 

particular vent.

Checking Off-ridge Vent Installations

Off-ridge vents typically have a flange that lies against the top surface of the roof sheathing and is used

to anchor the vent to the roof sheathing. Frequently, roofing nails are used to attach the flange to the roof

sheathing. The off-ridge vents should be checked to make sure that they are well anchored to the roof

sheathing. If they seem loose, or there are not many fasteners holding them down, it could be a weak link

in preventing water intrusion when a storm occurs. Since the flange and fasteners are hidden below the roof

covering, it is not possible to simply add nails or screws to improve the anchorage as these will create holes

through the roof covering.

Remedial Measures

If the off-ridge vent is attached to the roof sheathing with long, thin nails, it may be possible to improve the

anchorage by cinching the nails (bending them over against the underside of the roof sheathing). However, if

they are short and/or thick, trying to bend them over may cause more harm than good. Some homeowners

have had covers made that can be installed from the inside of the attic over the hole where the off-ridge

vent is installed. This will be easiest if the vent is larger than the hole and the cover can be attached to

the sheathing in an area where the fasteners can’t be driven through the roof covering. Otherwise, it will be

important to ensure that the fasteners are short enough that they won’t extend through the roof sheathing

and damage the roof cover. If the edge of the hole in the roof deck is flush with the inside edge of the vent, 

it may be possible to install metal straps that are screwed into the walls of the vent and attached with short

screws to the bottom surface of the roof sheathing. Again, it is critical to use screws that are short enough

that they won’t extend through the roof sheathing and damage the roof covering. The strapping should be

connected to the walls of the vent with short stainless steel sheet metal screws.

Gable Rake Vents

Key Issues

•	Gable rake vents are formed when porous soffit panels or screen vents are installed on the bottom surface

of the roof overhang at the gable end and there is a clear path for wind to blow into the attic. This usually

happens when the gable overhang is supported by what are called outriggers. Outriggers are typically

used when gable overhangs exceed 12". In these cases, the last roof truss or rafter (the gable end truss

or rafter) is smaller than the trusses or rafters at the next location inside the attic. Outriggers (2x4s) are

installed over top of the last gable truss or rafter, one end is anchored to the second truss or rafter back

from the gable end, and the other end sticks out past the gable end wall to support the roof sheathing on

the overhang.

Finding Out if You Have Gable Rake Vents and Whether You Still Need Them

The easiest way to tell if your roof has gable rake vents is to look in the attic on a cool sunny day and see

if light is visible in gaps just below the sheathing

at the gable end. The presence of the outriggers

(2x4s running perpendicular to the gable truss and

disappearing into the gable overhang) should also be

visible. If you also have a gable end vent or a ridge

vent, then you probably don’t need the gable rake vent

in order to provide adequate venting for your attic.

Remedial Measures

The best solution if you don’t actually need the venting

provided by the gable rake vents is to simply plug

them up with metal flashing (Figure 12) or pieces of

wood that are cut and anchored so that they are well 

attached and completely seal as many of the openings 

as possible and particularly those near the gable peak.

Sealant can be used to seal around the edges of the

metal or wood plugs. Figure 12. Metal plugs (red arrows) in gable rake vents.
Minimizing Water Intrusion Through Roof Vents in High-Wind Regions April 2009 Page 7 of 7

Turbines

Key Issues

•	The rotating top portion of many turbines is not designed to withstand high-wind conditions and they are

frequently installed with just a friction fit to the short standpipe that provides the venting of the attic. It is

possible to find high-wind rated turbines on store shelves in hurricane-prone regions but, in hurricane winds,

the turbines will be rotating at tremendous speeds and can be easily damaged by windborne debris.

•	The flange on the standpipe that provides the connection of the pipe to the roof sheathing may also be

poorly anchored to the roof sheathing.

Checking Turbines and Their Installation

Check any turbines to make sure that the stand pipes

are not loose and that the turbine head is anchored to

the stand pipe by sheet metal screws and not simply by

a friction fit (Figure 13).

Remedial Measures

Loose standpipes should be securely anchored to

the roof sheathing. If the standpipe is attached to 

the roof sheathing with long, thin nails, it may be

possible to improve the anchorage by cinching the

nails (bending them over against the underside of

the roof sheathing). However, if they are short and/or

thick, trying to bend them over may cause more harm

than good. Some homeowners have had covers made

that can be installed from the inside of the attic over

the hole where the standpipe is installed. This will be

easiest if the standpipe is larger than the hole and 

the cover can be attached to the sheathing in an area

where the fasteners can’t be driven through the roof cover. Otherwise, it will be important to ensure that the

fasteners are short enough that they won’t extend through the roof sheathing and damage the roof cover.

If the edge of the hole in the roof deck is flush with the inside edge of the standpipe, it may be possible to

install metal straps that are screwed into the walls of the standpipe and attached with short screws to the 

bottom surface of the roof sheathing. Again, it is critical to use screws that are short enough that they won’t

extend through the roof sheathing and damage the roof cover. The strapping should be connected to the

walls of the standpipe with short stainless steel sheet 

metal screws. Beyond any remedial measures taken 

to anchor the standpipe to the roof sheathing or to 

plug the hole from the attic side, it is also important 

to try and seal the standpipe from the outside so that 

water doesn’t build up in the pipe and leak into the roof

sheathing around the hole. The best approach is to

have a qualified person remove the top active portion

of the turbine vent before the storm and plug the hole

at the top of the standpipe. A wooden plug can be used

that covers the entire hole and has blocks that rest

against the walls of the standpipe where screws can 

be installed to anchor the plug to the standpipe. Some

homeowners have had the entire turbine wrapped in

plastic to keep water out during a storm (Figure 14).

This can work as long as the turbine or wrapping

doesn’t get dislodged. The smaller area provided

by removing the turbine top and plugging the hole is

considered preferable.

Figure 14. Plastic wrapped turbine.

Figure 13. This turbine head is attached to the standpipe 

with dimple punches. Sheet metal screws should be added to 

strengthen the connection. 

HURRICANE IKE RECOVERY ADVISORY

Metal Roof Systems in High-Wind Regions April 2009 Page 1 of 5

Purpose: To recommend practices for designing and installing metal roof systems that will enhance wind 

resistance in high-wind regions (i.e., greater than 90-miles per hour [mph] gust design wind speed). This 

Advisory is applicable to residential and commercial/industrial buildings and critical facilities.

Metal Roofing Options

A variety of metal panel systems (including composite foam panels) are available for low-slope (i.e., 3:12 or 

less) and steep-slope (i.e., greater than 3:12) roofs. Metal shingles are also available for steep-slope roofs. 

Common metal roofing options are:

Standing-Seam Hydrostatic (i.e., water-barrier) 

Systems: These panel systems are designed to resist 

water infiltration under hydrostatic pressure. They have 

standing seams, which raise the joint between panels 

above the water line. The seam is sealed with sealant 

tape or sealant in case it becomes inundated with water 

backed up by an ice dam or driven by high wind. 

Most hydrostatic systems are structural systems 

(i.e., the roof panel has sufficient strength to span 

between purlins or nailers). A hydrostatic architectural 

panel (which cannot span between supports) may be 

specified, however, if continuous or closely spaced 

decking is provided. 

Hydrokinetic (i.e., water-shedding) panels: 

These panel systems are not designed to resist water infiltration under hydrostatic pressure and therefore 

require a relatively steep slope (typically greater than 3:12) and the use of an underlayment to provide 

secondary protection against water that infiltrates past the panels. Most hydrokinetic panels are architectural 

systems, thus requiring continuous or closely spaced decking to provide support for gravity loads. 

Metal Roof Systems in

High-Wind Regions

This Recovery Advisory addresses wind and wind-driven rain issues. For general information on other 

aspects of metal roof system design and construction (including seam types, metal types, and finishes), 

see:

Architectural Sheet Metal Manual (Sheet Metal and Air Conditioning Contractors National Association, 

2003: http://www.smacna.org/bookstore

Copper and Common Sense: http://www.reverecopper.com/candcs.html

Copper Development Association: http://www.copper.org/publications/pub_list/architecture.html

Metal Construction Association: http://www.metalconstruction.org/pubs

Metal Roofing Systems Design Manual (Metal Building Manufacturers Association, 2000, 

http://www.mbma.com/display.cfm?p=44&pp6&i=47

National Institute of Building Sciences, Whole Building Design Guide:

http://www.wbdg.org/design/env_roofing.php

The NRCA Roofing Manual: Metal Panel and SPF Roof Systems (National Roofing Contractors 

Association, 2008, http://www.nrca.net/rp/technical/manual/default.aspx

http://www.fema.gov

An advantage of exposed fastener panels 

(versus panels with concealed clips) is that, 

after installation, it is easy to verify that the 

correct number of fasteners was installed. If 

fastening was not sufficient, adding exposed 

fasteners is easy and economical.

For attachment of corrugated metal panels, 

see FEMA 55, Coastal Construction Manual, 

Appendix K, available online at: http://www.

fema.gov/library/viewRecord.do?id=1671.
Metal Roof Systems in High-Wind Regions April 2009 Page 2 of 5

Some hydrokinetic panels have standing ribs and 

concealed clips (Figure 1), while others (such as 5Vcrimp panels, R-panels [box-rib] and corrugated panels) 

are through-fastened (i.e., attached with exposed 

fasteners). Panels are available that simulate the 

appearance of tile.

Metal Shingles: Metal shingles are hydrokinetic products 

and therefore also require a relatively steep-slope and 

the use of an underlayment. Metal shingles are available 

that simulate the appearance of wood shakes and tiles.

Key Issues

Damage investigations have revealed that some metal 

roofing systems have sufficient strength to resist 

extremely high winds (Figure 2), while other systems 

have blown off during winds that were well below design 

wind speeds given in ASCE 7. When metal roofing (or 

hip, ridge, or rake flashings) blow off during hurricanes, 

water may enter the building at displaced roofing; blownoff roofing can damage buildings and injure people. 

Guidance for achieving successful wind performance is 

presented below:

1. Always follow manufacturer’s installation instructions 

and local building code requirements. 

2. Calculate loads on the roof assembly in accordance 

with ASCE 7 or the local building code, whichever 

procedure results in the highest loads.

3. Specify/purchase a metal roof system that has 

sufficient uplift resist resistance to meet the design 

uplift loads.

•	For standing seam and through-fastened metal panel

systems, the International Building Code® (IBC®) 

requires test methods UL 580 or ASTM E 1592. For 

standing seam systems, it is recommended that 

design professionals specify E 1592 testing, because 

it gives a better representation of the system’s uplift 

performance capability. 

For safety factor determination, refer to Chapter F 

in standard NAS-01, published by the American Iron 

and Steel Institute (available online at: http://www.

professionalroofing.net/article.aspx?id=266).

•	For through-fastened steel panel systems, the IBC

allows uplift resistance to be evaluated by testing or by 

calculations in accordance with standard NAS-01. 

•	For architectural panels with concealed clips, test

method UL 580 is commonly used. However, it is 

recommended that design professionals specify E 

1592 because it gives a better representation of the 

system’s uplift performance capability. When testing 

architectural panel systems via E 1592, the deck joints 

need to be unsealed in order to allow air flow to the 

underside of the metal panels. Therefore, underlayment 

should be eliminated from the test specimen, and a 

Figure 2. This structural standing seam roof system survived 

Hurricane Andrew (Florida, 1992), but some hip flashings 

were blown off. The estimated wind speed was 170 mph 

(peak gust, Exposure C at 33 feet).

Figure 1. This architectural panel system has concealed 

clips. The panels unlatched from the clips. The first row of 

clips (just above the red line) was several inches from the 

end of the panels. The first row of clips should have been 

closer to the eave. 

For observations of metal roofing performance 

during Hurricanes Charley (2004, Florida), 

Ivan (2004, Alabama and Florida), and Katrina 

(Alabama, Louisiana, and Mississippi, 2005), 

respectively; see Chapter 5 in FEMA MAT 

reports 488, 489, and 549, available on-line 

at:

FEMA 488: http://www.fema.gov/library/

viewRecord.do?id=1444

FEMA 489: http://www.fema.gov/library/

viewRecord.do?id=1569

FEMA 549: http://www.fema.gov/library/

viewRecord.do?id=1857
Metal Roof Systems in High-Wind Regions April 2009 Page 3 of 5

1/8” minimum gap between deck panel side and end 

joints should be specified. 

For safety factor determination, refer to Chapter F in 

standard NAS-01.

•	For copper roofing testing, see “NRCA analyzes and

tests metal,” Professional Roofing, May 2003 (available 

online at: http://www.professionalroofing.net/article.

aspx?id=266).

•	For metal shingles, it is recommended that uplift

resistance be based on test method UL 580 or 1897.

•	Specify the design uplift loads for field, perimeter, and

corners of the roof. Also specify the dimension of the 

width of the perimeter. (Note: For small roof areas, the 

corner load can be used throughout the entire roof 

area.)

4. Suitably design the roof system components (see the 

construction guidance below).

5. Obtain the services of a professional roofing 

contractor to install the roof system. 

Construction Guidance 

•	Consult the local building code and manufacturer’s

literature for specific installation requirements. 

Requirements may vary locally.

•	Underlayment: If a robust underlayment system is

installed, it can serve as a secondary water barrier 

if the metal roof panels or shingles are blown off 

(Figures 1 and 3). For enhanced underlayment 

recommendations, see Technical Fact Sheet No. 19 in 

FEMA 499, Home Builder’s Guide to Coastal Construction 

Technical Fact Sheet Series (available online at: http://

www.fema.gov/library/viewRecord.do?id=1570). Fact 

Sheet 19 pertains to underlayment options for asphalt 

shingle roofs. For metal panels and tiles, where Fact 

Sheet 19 recommends a Type I (#15) felt, use a Type 

II (#30) felt because the heavier felt provides greater 

resistance to puncture by the panels during application. 

Also, if a self-adhering modified bitumen underlayment 

is used, specify/purchase a product that is intended 

for use underneath metal (such products are more 

resistant to bitumen flow under high temperature). 

•	Where the basic (design) wind speed is 110 mph or

greater, it is recommended that two clips be used along 

the eaves, ridges, and hips. Place the first eave clip 

within 2 to 3" of the eave, and place the second clip 

approximately 3 to 4" from the first clip. Figures 1 and 

4 illustrate ramifications of clips being too far from the 

eave.

•	For copper panel roofs in areas with a basic wind

speed greater than 90 mph, it is recommended that 

Type 316 stainless steel clips and stainless steel 

screws be used in lieu of the much more malleable 

copper clips. 

Figure 3. These architectural panel system have snap-lock 

seams. One side of the seam is attached with a concealed 

fastener. Although a large number of panels blew away, the 

underlayment did not.

Figure 4. These eave clips were too far from the panel ends. 

The clip at the left was 13" from the edge of the deck. 

The other clip was 17" from the edge. It would have been 

prudent to install double clips along the eave. 

Figure 5. The panels blew off the upper roof and landed on 

the lower roof of this house. The upper asphalt shingle roof 

shown had been re-covered with 5V-Crimp panels that were 

screwed to nailers. The failure was caused by inadequate 

attachment of the nailers (which had widely-spaced nails) to 

the sheathing. Note that the hip flashing on the lower roof 

blew off. 
Metal Roof Systems in High-Wind Regions April 2009 Page 4 of 5

•	When clip or panel fasteners are attached to nailers (Figures 5, 6, and 7), detail the connection of the nailer

to the nailer support (including the detail of where nailers are spliced over a support). 

•	When clip or panel fasteners are loaded in withdrawal (tension), screws are recommended in lieu of nails.

•	For roofs located within 3,000' of the ocean line, stainless steel clips and fasteners are recommended.

•	For concealed clips over a solid substrate, it is recommended that chalk lines be specified so that the clips

are correctly spaced. 

•	Hip, ridge, and rake flashings: Because exposed fasteners are more reliable than cleat attachment, it is

recommended that hip, ridge, and rake flashings be attached with exposed fasteners. Two rows of fasteners 

are recommended on either side of the hip/ridge line. Close spacing of fasteners is recommended (e.g., 

spacing in the range of 3 to 6" on center, commensurate with the design wind loads), as shown in Figure 8 

in order to avoid flashing blow-off as shown in Figure 9.

Figure 7. This residence had metal shingles that simulated 

the appearance of tile. The shingles typically blew off the 

battens, but some of the battens were also blown away.

Figure 6. Blow-off of nailers caused these panels to 

progressively fail. The nailers were installed directly over 

the trusses. In an assembly such as this where there is 

no decking, there is no opportunity to incorporate an 

underlayment. With loss of the panels, rainwater was free to 

enter the building.

Figure 8. The ridge flashing on these corrugated metal panels 

had two rows of fasteners on each side of the ridge line.

Figure 9. The ridge flashing fasteners were placed too far 

apart. A significant amount of water leakage can occur when 

ridge flashings are blown away. 
Metal Roof Systems in High-Wind Regions April 2009 Page 5 of 5

Sustainable Design

Cool Roofs: Use metal roofs with a solar reflectance Index (SRI) equal to or greater than 78 for low-slope 

and 29 for steep-sloped roofs. The higher solar reflectance will reduce the heat-island effect (thermal 

gradient differences between developed and undeveloped areas), minimizing the impact buildings have

on microclimate and human and wildlife habitat. Heat islands can affect communities by increasing 

summertime peak energy demand, air conditioning costs, greenhouse gas emissions and air pollution, 

heat-related illness and mortality, and water quality (http://www.EPA.gov/heatisland).

Recycled Content: Use metal roof systems with recycled content. Many roofing products have recycled 

scrap content generated both from consumer and industrial users. Recycled content is defined in the 

International Organization of Standards (ISO) document, ISO 14021 (http://www.iso.org/iso/catalogue_

detail?csnumber=23146). Using recycled products reduces impacts from extraction and processing of 

new materials.

For further information pertaining to sustainable design aspects of metal roofing, see: http://www.

metalconstruction.org/design.

Critical Facilities 

For metal roofs on critical facilities in hurricane-prone regions (as defined in ASCE 7), see the 

recommendations in FEMA 543, Section 3.4.3.4 (available online at http://www.fema.gov/library/

viewRecord.do?id=2441). (For facilities located outside of hurricane-prone regions, see Section 3.3.3.4.) 

For load calculation recommendations, see Section 3.3.1.2.

For metal roofs on hospitals in hurricane-prone regions, see the recommendations in FEMA 577, Section 

4.3.3.8 (available online at http://www.fema.gov/library/viewRecord.do?id=2739). (For hospitals located 

outside of hurricane-prone regions, see Section 4.3.3.7.) For load calculation recommendations, see 

Section 4.3.1.2.

Siding Installation in

High-Wind Regions

HURRICANE IKE RECOVERY ADVISORY

Siding Installation in High-Wind Regions January 2009 Page 1 of 7

Purpose: To provide basic design and installation tips for various types of siding that will enhance wind 

resistance in high-wind regions (i.e., greater than 90-mph gust design wind speed).

Key Issues

•	Siding is frequently blown off walls of residential and

non-residential buildings during hurricanes. Also, winddriven rain is frequently blown into wall cavities (even

when the siding itself is not blown off). Guidance for 

achieving successful wind performance is presented 

below.

•	To avoid wind-driven rain penetration into wall cavities, an

effective moisture barrier (housewrap or building paper) 

is needed. For further information on moisture barriers, 

see Technical Fact Sheet No. 9 in FEMA 499, Home 

Builder’s Guide to Coastal Construction, Technical Fact 

Sheet Series (available online at: http://www.fema.gov/

library/viewRecord.do?id=1570). For further information 

on housewrap, see Technical Fact Sheet No. 23.

•	Always follow manufacturer’s installation instructions and

local building code requirements.

•	Use products that are suitable for a coastal environment.

Many manufacturers do not rate their products in a way

that makes it easy to determine whether the product 

will be adequate for the coastal environment. Use only

siding products where the supplier can provide specific 

information on product performance in coastal or highwind environments.

•	For buildings located within 3,000' of the ocean line,

stainless steel fasteners are recommended. 

•	Avoid using dissimilar metals together.

•	The installation details for starting the first (lowest) course of lap siding can be critical. Loss of siding often

begins at the lowest course and proceeds up the wall (Figures 4 and 12). This is particularly important for

elevated buildings, where the wind blows under the building as well as against the sides.

•	When applying new siding over existing siding, use shims or install a solid backing to create a uniform, flat

surface on which to apply the siding, and avoid creating gaps or projections that could catch the wind.

•	Coastal buildings require more maintenance than inland buildings. This maintenance requirement needs to

be considered in both the selection and installation of siding.

Vinyl Siding

Vinyl siding can be used successfully in a coastal environment if properly designed and installed.

•	Windload resistance:

Moisture barrier (also known as a 

water-resistive barrier): In the context of

residential walls, the moisture barrier is 

either housewrap or building paper (felt). 

The moisture barrier occurs between the 

wall sheathing and the siding. It is a dualpurpose layer that sheds water that gets 

through the siding and limits air flow through

the wall. When properly sealed, housewrap

is considered an air barrier. Although 

building paper provides some resistance to 

air flow, it is not considered an air barrier.

Moisture barriers shed water, but they allow

water vapor to pass through them.

For further guidance on principles, 

materials, and procedures for the design 

and construction of walls to make them 

resistant to water intrusion, see American 

Society for Testing and Materials (ASTM)

E 2266, Standard Guide for Design and 

Construction of Low-Rise Frame Building Wall 

Systems to Resist Water Intrusion.

http://www.fema.gov
Siding Installation in High-Wind Regions January 2009 Page 2 of 7

•	Vinyl siding is required by the International Building

Code®(IBC®) and the International Residential

Code®(IRC®) to comply with ASTM D 3679,

Standard Specification for Rigid Poly(Vinyl Chloride) 

(PVC) Siding, which requires the siding to withstand

wind pressures equivalent to 110 mph on a

building up to 30' in height in Exposure B. Most

vinyl siding has also been tested for higher wind 

pressures, and can be used in locations with a 

higher basic wind speed, greater building height, more open exposure, or some combination of those.

The design wind pressure or wind speed for which these products are rated is available from product 

literature, installation instructions, or listings of agencies such as the International Code Council®

(ICC®) Evaluation Service.

•	For design wind speeds greater than 110 mph, or building heights greater than 30', or Exposure C,

choose a model of siding rated for those conditions or higher. The manufacturer’s product literature or

installation instructions should specify the fastener type, size and spacing, and any other installation 

details needed to achieve this rating.

•	Products that have been rated for high winds

typically have an enhanced nailing hem and are 

sometimes made from thicker vinyl (Figure 1).

Thick, rigid panels provide greater wind resistance, 

withstand dents, and lie flatter and straighter

against the wall. Optimum panel thickness should 

be 0.040 to 0.048", depending on style and

design. Thinner gauge vinyl works well for stable 

climates; thicker gauge vinyl is recommended 

for areas with high winds and high temperature 

changes.

•	Position nails in the center of the nailing slot

(Figure 2).

•	To allow for thermal movement of the siding, do not

drive the head of the nail tight against the nail hem 

(unless the hem has been specifically designed 

for this). Allow approximately 1/32" (which is about the

thickness of a dime) clearance between the fastener head 

and the siding panel (Figure 3).

•	Drive nails straight and level to prevent

distortion and buckling in the panel.

•	Do not caulk the panels where they meet the

receiver of inside corners, outside corners, or 

J-trim. Do not caulk the overlap joints.

•	Do not face-nail or staple through the siding.

•	Use aluminum, galvanized steel, or other

corrosion-resistant nails when installing vinyl 

siding. Aluminum trim pieces require aluminum or stainless steel fasteners.

•	Nail heads should be 5/16" minimum in diameter. Shank should be 1/8" in

diameter.

•	Use the manufacturer-specified starter strip to lock in the first course; do not substitute other accessories

such as a J-channel or utility trim (Figure 4) unless specified by the manufacturer. If the manufacturer

specifies a particular strip for high-wind applications, use it. Make sure that the starter strip is designed

to positively lock the panel, rather than just hooking over a bulge in the strip; field test the interlock before 

proceeding with the installation.

Figure 1. Features of typical high-wind siding and 

standard siding. 

Definition of Wind Exposure Zones

Exposure B: Urban, suburban, wooded areas.

Exposure C: Open terrain, flat open country,

grasslands, all water surfaces in hurricaneprone regions.

High-wind siding Standard siding

Figure 2. Proper and improper 

fastener locations.

Figure 3. Allow 1/32” 

clearance between the 

fastener head and the 

siding panel.
Siding Installation in High-Wind Regions January 2009 Page 3 of 7

•	Make sure that every course of siding is positively

locked into the previous course (Figure 5). Push

the panel up into the lock from the bottom before 

nailing rather than pulling from the top. Do not

attempt to align siding courses with adjacent walls 

by installing some courses loosely.

•	Make sure that adjacent panels overlap properly,

about half the length of the notch at the end of the 

panel, or approximately 1". Make sure the overlap

is not cupped or gapped, which is caused by pulling 

up or pushing down on the siding while nailing. 

Reinstall any panels that have this problem.

•	Use utility trim under windows or anywhere the top

nail hem needs to be cut from siding to fit around 

an obstacle. Be sure to punch snap-locks into the

siding to lock into the utility trim. Do not overlap

siding panels directly beneath a window (Figure 6).

•	At gable end walls, it is recommended that vinyl siding be installed

over wood sheathing rather than over plastic foam sheathing, as 

was done at the house shown in Figure 7. 

•	Install vinyl siding in accordance with manufacturer’s installation

instructions and local building code requirements. 

•	It is recommended that vinyl siding installers be certified under

the VSI Certified Installer Program sponsored by the Vinyl Siding

Institute. For more information, go to http://www.vinylsiding.org/

aboutsiding/installation/certinstaller. 

Figure 4. Utility trim was substituted for the starter strip and 

the bottom lock was cut off the siding. Siding was able to pull 

loose under wind pressure. 

Figure 7. The vinyl siding at this gable was installed over plastic 

foam insulation. Without wood sheathing, the wind pressures on 

the vinyl are increased. Also, if the siding blows away, the foam 

insulation is very vulnerable to blow-off. With loss of the foam 

insulation, wind-driven rain can freely enter the attic, saturate 

the ceiling insulation, and cause collapse of the ceiling.

Figure 5. The siding panel was not properly 

locked into the panel below. 

Figure 6. Proper detailing around windows and other obstacles 

is important. Use utility trim, punch snap-locks into siding, and 

don’t overlap directly beneath a window. 
Siding Installation in High-Wind Regions January 2009 Page 4 of 7

Wood Siding

•	Use decay-resistant wood such as redwood, cedar, or cypress. See the Sustainable Design section regarding

certified wood.

•	To improve longevity of paint, back-prime wood siding before installation.

•	Carefully follow manufacturer’s detailing instructions to prevent excessive water intrusion behind the siding.

•	For attachment recommendations, see Natural Wood Siding: Selection, Installation and Finishing, published 

by the Western Wood Products Association (http://www.wwpa.org).

This publication recommends an air gap between the moisture barrier and the backside of the siding to 

promote drainage and ventilation. Such a wall configuration is referred to as a rain screen wall. See the text

box on page 5.

•	Follow the installation details shown in Figure 8. (Note: Although these details do not show a rain screen,

inclusion of vertical furring strips to create a rain screen is recommended.) 

Figure 8. Wood siding installation details.
Siding Installation in High-Wind Regions January 2009 Page 5 of 7

Fiber Cement Siding

Installation procedures are similar to those for wood siding, but require specialized cutting blades and

safety precautions because of the dust produced during cutting with power tools. Manufacturer’s installation

recommendations should be strictly adhered to, and particular attention paid to the painting and finishing 

recommendations for a high-quality installation.

•	Always seal field-cut ends according to the manufacturer’s instructions. Properly gap the intersection

between siding edges and other building components and fill the gap with sealant.

•	Always consult and follow the manufacturer’s installation requirements for the needed wind speed rating

or design pressure (refer to the manufacturer’s building code compliance evaluation report). Observe

the manufacturer’s fastener specifications, including fastener type and size, spacing, and penetration

requirements. Do not over drive or under drive.

•	At gable end walls, it is recommended that fiber cement siding be installed over wood sheathing rather than

over plastic foam sheathing.

•	Keep blind nails between 3⁄4 and 1" from the top edge of the panel (Figure 10). Be sure to drive nails at

least 3/8" from butt ends, or use manufacturer-specified joiners.

•	Face nailing (Figure 11) instead of blind nailing is recommended where the basic (design) wind speed is 100

miles per hour or greater. If the local building code or manufacturer specifies face nailing at a lower wind

speed, install accordingly.

•	Do not leave the underside of the first course exposed or extending beyond the underlying material (Figure

12). Consider the use of a trim board to close off the underside of the first course.

Pressure-equalized rain screen wall system

In areas that experience frequent wind-driven rain and

areas susceptible to high winds, it is recommended that a 

rain screen design be considered when specifying wood or 

fiber cement siding. (Typical vinyl siding products inherently 

provide air cavities behind the siding that facilitate drainage. 

Therefore, incorporation of vertical furring strips is normally 

not applicable to this type of wall covering.) A rain screen 

design is accomplished by installing suitable vertical furring 

strips between the moisture barrier and siding material (see 

Figure 9). The cavity facilitates drainage of water from the 

space between the moisture barrier and backside of the siding 

and it facilitates drying of the siding and moisture barrier.

Furring strip attachment: For 1" x 2" furring strips, tack strips 

in place and use siding nails that are 3⁄4" longer than would 

be required if there were no strips (thereby maintaining the

minimally required siding nail penetration into the studs).

For thicker furring strips, an engineered attachment is 

recommended.

At the bottom of the wall, the cavity should be open to allow 

water drainage. However, the opening should be screened to 

avoid insect entry. 

At the wall/soffit juncture, the top of the cavity can open into the attic space to provide inlet air

ventilation, thereby eliminating soffit vents and their susceptibility to wind-driven rain entry. If the rain

screen cavity vent path is used in lieu of soffit vents, the depth of the cavity needs to be engineered to 

ensure that it provides sufficient air flow to ventilate the attic.

Figure 9. Pressure-equalized rain screen 

system.
Siding Installation in High-Wind Regions January 2009 Page 6 of 7

Sustainable Design

Material selection for sustainable sources and 

durability

For wood products, select a Forest Stewardship Council

(FSC) certified product. The FSC seeks to ensure that

wood is harvested in a more responsible fashion, 

including protecting forest ecosystems, and avoids 

the use of chemicals and genetic engineering. While

redwood, cedar, and cypress are decay-resistant and 

recommended for durability, they are generally cut from 

old growth timber. You can determine if the manufacturer 

is FSC certified by going to http://www.fsc-info.org.

For other siding products, consider long-term life spans 

for coastal environments, recycled content, and postconsumer use.

The following publications discuss sustainable aspects of vinyl siding:

A Dozen Things You Might Not Know That Make Vinyl Siding Green (available online at http://www.vinylsiding.

org/aboutsiding/greenpaper/080919_VSI_Green_Paper_for_web.pdf).

Siding with the Environment (available online at http://www.vinylsiding.org/publications/final_Enviro_single_

pg.pdf).

Energy Conservation and Air Barriers: Uncontrolled air leakage through the building envelope is often

overlooked. The U.S. Department of Energy estimates that 40 percent of the cost of heating or cooling the

average American home is lost to uncontrolled air leakage. In warmer climates, it is a lower percentage of

loss. An air barrier system can reduce the heating, ventilation, and cooling (HVAC) system size, resulting in

reduced energy use and demand.

Uncontrolled air leakage can also contribute to premature deterioration of building materials, mold and

moisture problems, poor indoor air quality, and compromised occupant comfort. When uncontrolled air

flows through the building envelope, water vapor moves with it. Controlling the movement of moisture by air

infiltration requires controlling the air pathways and/or the driving force.

To effectively control air leakage through the building envelope, an effective air barrier is required. To be

effective, it needs to be continuous; therefore, air barrier joints need to be sealed and the barrier needs to 

be sealed at penetrations through it. The Air Barrier Association of America recommends that materials used

Figure 11. Face nailing. 

Figure 12. Blind nailed siding installed with exposed gap at 

bottom (red circle) is vulnerable to failure.

Figure 10. Blind nailing. 
Siding Installation in High-Wind Regions January 2009 Page 7 of 7

as a component of a building envelope air barrier be tested to have an air infiltration rate of less than 0.004

cfm/square foot, assemblies of materials that form the air barrier be tested to have an air infiltration rate of

less than 0.04 cubic feet per minute (cfm)/square foot, and the whole building exterior enclosure have an air

infiltration rate of less than 0.4 cfm/square foot.

Air barrier systems installed behind siding:

Housewrap is the most common air barrier material for 

residential walls. To be effective, it is critical that the joints 

between sheets of housewrap be sealed as recommended 

by the manufacturer, and penetrations (other than 

fasteners) should also be sealed. At transitions between 

the housewrap and door and window frame, use of selfadhering modified bitumen flashing tape is recommended.

An air barrier should be installed over a rigid material, or 

it will not function properly. It also needs to be restrained

from pulling off of the wall under negative wind pressures. 

For walls, wood sheathing serves as a suitable substrate, 

and the siding (or furring strips in a rain screen wall 

system) provide sufficient restraint for the air barrier. 

At the base of the wall, the wall air barrier should be 

sealed to the foundation wall. If the house is elevated on

piles, the wall barrier should be sealed to an air barrier 

installed at the plane of the floor.

If the building has a ventilated attic, at the top of the wall,

the wall air barrier should be sealed to an air barrier that 

is installed at the plane of the ceiling. 

If the building has an unventilated attic or no attic, at the

top of the wall, the wall air barrier should be sealed to an 

air barrier that is installed at the plane of the roof (the roof 

air barrier may be the roof membrane itself, or a separate 

air barrier element). 

Siding maintenance:

For all siding products, it is very important to periodically 

inspect and maintain the product especially in a coastal 

environment. This includes recoating on a scheduled 

maintenance plan that is necessary according to the 

manufacturer’s instructions and a periodic check of the

sealant to ensure its durability. Check the sealant for its

proper resiliency and that it is still in place. Sealant should

be replaced before it reaches the end of its service life.

Air barrier: A component installed to provide 

a continuous barrier to the movement of air 

through the building envelope. Housewrap is 

a common air barrier material for residential 

walls. Although very resistant to airflow,

housewrap is very vapor permeable and 

therefore is not suitable for use as a vapor 

retarder.

Vapor retarder: A component installed to 

resist diffusion of water vapor and provide 

a continuous barrier to movement of air 

through the building envelope. Polyethylene

is a common vapor retarder material for 

residential walls. To determine whether 

or not a vapor retarder is needed, refer 

to the Moisture Control section of the

NRCA Roofing and Waterproofing Manual, 

published by the National Roofing

Contractors Association (NRCA) (http://

www.nrca.net).

ASTM E 1677, Standard Specification for 

an Air Retarder (AR) Material or System 

for Low-Rise Framed Building Walls:

This specification covers the minimum 

performance and acceptance criteria 

for an air barrier material or system for 

framed walls of low-rise buildings with the 

service life of the building wall in mind. The 

provisions contained in this specification are 

intended to allow the user to design the wall 

performance criteria and increase air barrier 

specifications to accommodate a particular 

climate location, function, or design of the 

intended building.

HURRICANE IKE IN TEXAS ANd LoUISIANA MITIGATION ASSESSMENT TEAM REPORT E-1

HIGH WATER MARKS E

High Water Marks

The following HWM data is taken from FEMA’s Texas Hurricane Ike 

Rapid Response Coastal High Water Mark Collection (October 2008).

EHigh Water Marks

HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT E-3

HIGH WATER MARKS E

High Water Marks

in Texas

HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT E-5

HIGH WATER MARKS E

Summary of High Water Mark Survey Results

HWM ID Parish

Surveyed 

Elevation (feet) 

NAVD 88

Surveyed 

Latitude

Surveyed 

Longitude Flood Type

353-ITX-02-027 Brazoria 6.6 29.3030 -95.2668 Coastal - Stillwater Only

353-ITX-02-028 Brazoria 6.9 29.2479 -95.2363 Coastal - Stillwater Only

353-ITX-02-029 Brazoria 8.8 29.1966 -95.2989 Coastal - Stillwater Only

353-ITX-02-030 Brazoria 5.1 29.1127 -95.3745 Coastal - Stillwater Only

353-ITX-02-031 Brazoria 5.3 28.9490 -95.5553 Coastal - Stillwater Only

353-ITX-02-032 Brazoria 5.5 28.8778 -95.4558 Coastal - Stillwater Only

353-ITX-02-033 Brazoria 7.2 28.8981 -95.3807 Coastal - Stillwater Only

353-ITX-02-034 Brazoria 6.6 28.9506 -95.3384 Coastal - Stillwater Only

353-ITX-02-035 Brazoria 7.3 28.9395 -95.2972 Coastal - Stillwater Only

353-ITX-02-036 Brazoria 7.7 28.9429 -95.2999 Coastal - Stillwater Only

353-ITX-02-037 Brazoria 10.7 28.9538 -95.2820 Coastal - Stillwater Only

353-ITX-02-038 Brazoria 7.7 28.9620 -95.2908 Coastal - Stillwater Only

353-ITX-04-011 Brazoria 8.3 28.9301 -95.3130 Coastal - Stillwater Only

353-ITX-04-012 Brazoria 8.7 28.9301 -95.3128 Coastal - Wave Height

353-ITX-04-013 Brazoria 7.8 28.9354 -95.3038 Coastal - Stillwater Only

353-ITX-04-014 Brazoria 8.0 28.9484 -95.2924 Coastal - Stillwater Only

353-ITX-04-015 Brazoria 9.2 28.9626 -95.2734 Coastal - Stillwater Only

353-ITX-04-016 Brazoria 6.7 29.0136 -95.3308 Coastal - Stillwater Only

353-ITX-04-017 Brazoria 6.3 29.0955 -95.2839 Coastal - Stillwater Only

353-ITX-04-018 Brazoria 6.4 29.2098 -95.2105 Coastal - Stillwater Only

353-ITX-04-019 Brazoria 9.4 29.2845 -95.1294 Coastal - Stillwater Only

353-ITX-03-001 Chambers 14.8 29.8755 -94.8295 Coastal - Stillwater Only

353-ITX-03-002 Chambers 12.9 29.8476 -94.8044 Coastal - Wave Runup

353-ITX-03-003 Chambers 12.5 29.6793 -94.9254 Coastal - Wave Height

353-ITX-03-004 Chambers 12.9 29.6599 -94.9165 Coastal - Wave Height

353-ITX-03-005 Chambers 17.2 29.6945 -94.8654 Coastal - Wave Runup

353-ITX-03-006 Chambers 15.4 29.7486 -94.8252 Coastal - Wave Height

353-ITX-03-007 Chambers 13.8 29.8379 -94.7588 Coastal - Wave Runup

353-ITX-03-008 Chambers 15.7 29.7729 -94.6856 Coastal - Wave Runup

353-ITX-03-009 Chambers 13.5 29.6584 -94.6895 Coastal - Stillwater Only

353-ITX-03-010 Chambers 16.6 29.7282 -94.6902 Coastal - Stillwater Only

353-ITX-03-011 Chambers 11.6 29.6816 -94.6412 Coastal - Stillwater Only

353-ITX-03-012 Chambers 15.4 29.6635 -94.6241 Coastal - Stillwater Only

353-ITX-03-013 Chambers 10.5 29.5380 -94.7614 Coastal - Stillwater Only

353-ITX-03-014 Chambers 12.4 29.5260 -94.7581 Coastal - Wave Height

353-ITX-03-015 Chambers 15.3 29.6320 -94.7023 Coastal - Stillwater Only

353-ITX-03-016 Chambers 14.5 29.6135 -94.5332 Coastal - Stillwater Only

353-ITX-03-019 Chambers 16.9 29.7149 -94.3755 Coastal - Stillwater Only

353-ITX-03-020 Chambers 17.5 29.7040 -94.4837 Coastal - Stillwater Only

353-ITX-02-001 Galveston 10.3 29.0957 -95.1097 Coastal - Stillwater Only

353-ITX-02-002 Galveston 7.9 29.1299 -95.0585 Coastal - Stillwater Only

353-ITX-02-003 Galveston 10.3 29.1476 -95.0300 Coastal - Wave Runup

353-ITX-02-004 Galveston 10.8 29.1894 -94.9777 Coastal - Stillwater Only
E-6 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

E HIGH WATER MARKS

Summary of High Water Mark Survey Results

HWM ID Parish

Surveyed 

Elevation (feet) 

NAVD 88

Surveyed 

Latitude

Surveyed 

Longitude Flood Type

353-ITX-02-005 Galveston 10.5 29.2445 -94.8743 Coastal - Stillwater Only

353-ITX-02-006 Galveston 14.2 29.4726 -94.5955 Coastal - Wave Height

353-ITX-02-007 Galveston 15.8 29.4615 -94.6302 Coastal - Wave Runup

353-ITX-02-008 Galveston 14.8 29.4273 -94.6911 Coastal - Wave Height

353-ITX-02-009 Galveston 10.6 29.3651 -94.7758 Coastal - Wave Height

353-ITX-02-010 Galveston 15.6 29.3243 -94.7414 Coastal - Wave Height

353-ITX-02-011 Galveston 12.0 29.3073 -94.7941 Coastal - Stillwater Only

353-ITX-02-012 Galveston 13.2 29.3370 -94.7774 Coastal - Wave Height

353-ITX-02-013 Galveston 12.4 29.2755 -94.8504 Coastal - Wave Runup

353-ITX-02-014 Galveston 11.9 29.2952 -94.9168 Coastal - Stillwater Only

353-ITX-02-015 Galveston 11.8 29.3003 -94.9152 Coastal - Stillwater Only

353-ITX-02-016 Galveston 12.8 29.3614 -94.9207 Coastal - Wave Runup

353-ITX-02-017 Galveston 15.5 29.3911 -94.8873 Coastal - Wave Runup

353-ITX-02-019 Galveston 11.4 29.4578 -95.0210 Coastal - Stillwater Only

353-ITX-02-020 Galveston 10.4 29.4572 -95.0475 Coastal - Stillwater Only

353-ITX-02-021 Galveston 10.9 29.4365 -95.0922 Coastal - Stillwater Only

353-ITX-02-022 Galveston 13.4 29.3810 -95.0891 Coastal - Stillwater Only

353-ITX-02-023 Galveston 10.3 29.3422 -95.0368 Coastal - Stillwater Only

353-ITX-02-024 Galveston 12.2 29.3043 -94.9876 Coastal - Stillwater Only

353-ITX-02-025 Galveston 10.9 29.3348 -94.9779 Coastal - Stillwater Only

353-ITX-03-017 Galveston 15.4 29.5697 -94.3962 Coastal - Wave Runup

353-ITX-03-018 Galveston 19.4 29.5574 -94.3916 Coastal - Wave Runup

353-ITX-04-001 Galveston 9.7 29.0912 -95.1115 Coastal - Wave Runup

353-ITX-04-002 Galveston 10.7 29.0931 -95.1107 Coastal - Wave Runup

353-ITX-04-003 Galveston 10.7 29.1326 -95.0602 Coastal - Wave Height

353-ITX-04-004 Galveston 9.4 29.1315 -95.0588 Coastal - Stillwater Only

353-ITX-04-005 Galveston 10.2 29.1497 -95.0303 Coastal - Wave Runup

353-ITX-04-006 Galveston 10.2 29.1494 -95.0279 Coastal - Wave Runup

353-ITX-04-007 Galveston 14.1 29.1737 -94.9977 Coastal - Wave Height

353-ITX-04-008 Galveston 10.7 29.1866 -94.9655 Coastal - Stillwater Only

353-ITX-04-009 Galveston 13.1 29.2365 -94.8830 Coastal - Wave Height

353-ITX-04-010 Galveston 11.0 29.3273 -94.7720 Coastal - Wave Height

353-ITX-04-020 Galveston 10.4 29.3355 -95.0224 Coastal - Stillwater Only

353-ITX-04-021 Galveston 10.6 29.3371 -95.0244 Coastal - Stillwater Only

353-ITX-04-028 Galveston 16.7 29.5356 -95.0115 Coastal - Wave Height

353-ITX-04-029 Galveston 15.4 29.5356 -95.0115 Coastal - Stillwater Only

353-ITX-04-030 Galveston 15.2 29.5117 -94.9788 Coastal - Stillwater Only

353-ITX-04-031 Galveston 12.4 29.5007 -94.9347 Coastal - Stillwater Only

353-ITX-04-032 Galveston 12.2 29.4644 -94.9743 Coastal - Wave Runup

353-ITX-04-022 Harris 12.8 29.6155 -94.9980 Coastal - Stillwater Only

353-ITX-04-023 Harris 12.5 29.6195 -95.0071 Coastal - Wave Height

353-ITX-04-024 Harris 12.9 29.5652 -95.0170 Coastal - Stillwater Only

353-ITX-04-025 Harris 10.6 29.5649 -95.0690 Coastal - Wave Height
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT E-7

HIGH WATER MARKS E

Summary of High Water Mark Survey Results

HWM ID Parish

Surveyed 

Elevation (feet) 

NAVD 88

Surveyed 

Latitude

Surveyed 

Longitude Flood Type

353-ITX-04-026 Harris 10.9 29.5386 -95.0851 Coastal - Stillwater Only

353-ITX-01-001 Jefferson 12.2 29.8666 -93.9343 Coastal - Wave Runup

353-ITX-01-002 Jefferson 11.9 29.9195 -93.8895 Coastal - Wave Runup

353-ITX-01-003 Jefferson 11.4 29.8654 -93.9314 Coastal - Wave Runup

353-ITX-01-004 Jefferson 11.7 29.8652 -93.9273 Coastal - Wave Runup

353-ITX-01-005 Jefferson 11.7 29.9486 -93.8769 Coastal - Wave Runup

353-ITX-01-006 Jefferson 11.8 29.9720 -93.8633 Coastal - Stillwater Only

353-ITX-01-007 Jefferson 12.2 29.9721 -93.8633 Coastal - Wave Height

353-ITX-01-016 Jefferson 11.1 30.0963 -94.0933 Coastal - Stillwater Only

353-ITX-01-017 Jefferson 11.2 30.0830 -94.0943 Coastal - Wave Runup

353-ITX-01-019 Jefferson 11.8 29.9964 -93.9498 Coastal - Stillwater Only

353-ITX-01-020 Jefferson 11.5 29.9689 -93.9134 Coastal - Stillwater Only

353-ITX-03-021 Jefferson 9.4 29.8785 -94.1604 Coastal - Stillwater Only

353-ITX-03-022 Jefferson 11.3 29.8494 -94.1350 Coastal - Stillwater Only

353-ITX-03-023 Jefferson 13.0 29.7309 -93.8971 Coastal - Stillwater Only

353-ITX-03-024 Jefferson 11.7 29.8872 -94.0432 Coastal - Wave Runup

353-ITX-03-025 Jefferson 13.6 29.7945 -94.2279 Coastal - Stillwater Only

353-ITX-03-026 Jefferson 9.2 29.9434 -94.1302 Coastal - Stillwater Only

353-ITX-03-027 Jefferson 9.6 29.9965 -94.1065 Coastal - Stillwater Only

353-ITX-03-028 Jefferson 11.6 30.0818 -94.0932 Coastal - Stillwater Only

353-ITX-03-029 Jefferson 8.8 30.0279 -94.1491 Coastal - Stillwater Only

353-ITX-03-030 Jefferson 12.8 29.8694 -93.9325 Coastal - Wave Runup

353-ITX-03-031 Jefferson 11.7 29.8224 -93.9637 Coastal - Wave Height

353-ITX-01-008 Orange 10.2 30.0181 -93.8486 Coastal - Stillwater Only

353-ITX-01-009 Orange 13.1 30.0154 -93.8370 Coastal - Stillwater Only

353-ITX-01-010 Orange 8.7 30.0915 -93.7268 Coastal - Stillwater Only

353-ITX-01-011 Orange 9.6 30.0773 -93.7448 Coastal - Stillwater Only

353-ITX-01-012 Orange 9.3 30.0741 -93.7236 Coastal - Stillwater Only

353-ITX-01-013 Orange 11.8 30.0748 -93.8493 Coastal - Stillwater Only

353-ITX-01-014 Orange 12.9 30.0507 -93.9184 Coastal - Stillwater Only

353-ITX-01-015 Orange 10.8 30.0972 -94.0671 Coastal - Stillwater Only

353-ITX-01-018 Orange 12.7 30.0535 -93.9735 Coastal - Stillwater Only

353-ITX-01-021 Orange 9.9 30.2270 -93.7379 Coastal - Stillwater Only

353-ITX-01-022 Orange 7.7 30.1564 -93.7077 Coastal - Stillwater Only

353-ITX-01-023 Orange 8.3 30.1774 -93.7074 Coastal - Stillwater Only

353-ITX-01-024 Orange 10.8 30.0475 -93.7716 Coastal - Stillwater Only

353-ITX-01-025 Orange 9.4 30.0660 -93.7456 Coastal - Stillwater Only

353-ITX-01-026 Orange 10.7 30.0452 -93.8139 Coastal - Stillwater Only

353-ITX-01-027 Orange 10.9 30.0957 -94.0893 Coastal - Stillwater Only

353-ITX-01-028 Orange 11.7 30.0964 -94.0573 Coastal - Stillwater Only

HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT E-9

HIGH WATER MARKS E
E-10 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

E HIGH WATER MARKS
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT E-11

HIGH WATER MARKS E
E-12 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

E HIGH WATER MARKS
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT E-13

HIGH WATER MARKS E
E-14 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

E HIGH WATER MARKS
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT E-15

HIGH WATER MARKS E

HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT E-17

HIGH WATER MARKS E

High Water Marks

in Louisiana

HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT E-19

HIGH WATER MARKS E

Summary of High Water Mark Survey Results

HWM ID Parish

Surveyed 

Elevation (feet) 

NAVD 88

Surveyed 

Latitude

Surveyed 

Longitude Flood Type

401-ILA-02-009 Acadia 3.8 30.0817 -92.5062 Coastal - Stillwater Only

401-ILA-02-011 Acadia 3.5 30.1898 -92.5898 Coastal - Stillwater Only

401-ILA-01-006 Ascension 4.1 30.1906 -90.7862 Coastal - Stillwater Only

401-ILA-01-012 Ascension 3.8 30.1735 -90.7880 Coastal - Stillwater Only

401-ILA-03-005 Assumption 4.1 30.0006 -91.1932 Coastal - Stillwater Only

401-ILA-03-006 Assumption 3.1 29.9570 -91.2020 Coastal - Stillwater Only

401-ILA-03-007 Assumption 2.9 29.9008 -91.1861 Coastal - Stillwater Only

401-ILA-03-008 Assumption 2.9 29.8664 -91.1081 Coastal - Stillwater Only

401-ILA-03-012 Assumption 3.1 29.9366 -91.2213 Coastal - Stillwater Only

401-ILA-05-005 Calcasieu 8.7 30.1032 -93.3361 Coastal - Stillwater Only

401-ILA-05-006 Calcasieu 9.2 30.1140 -93.3417 Coastal - Stillwater Only

401-ILA-05-007 Calcasieu 5.6 30.0659 -93.3484 Coastal - Stillwater Only

401-ILA-05-013 Calcasieu 5.5 30.1910 -93.2680 Coastal - Stillwater Only

401-ILA-05-014 Calcasieu 9.2 30.1689 -93.2985 Coastal - Stillwater Only

401-ILA-05-015 Calcasieu 9.3 30.1043 -93.3063 Coastal - Stillwater Only

401-ILA-05-022 Calcasieu 4.5 30.1296 -92.9077 Coastal - Stillwater Only

401-ILA-05-027 Calcasieu 9.6 30.2366 -93.2300 Coastal - Stillwater Only

401-ILA-05-028 Calcasieu 8.4 30.2193 -93.2233 Coastal - Stillwater Only

401-ILA-05-029 Calcasieu 9.3 30.2110 -93.2356 Coastal - Stillwater Only

401-ILA-05-030 Calcasieu 9.2 30.2036 -93.2393 Coastal - Stillwater Only

401-ILA-05-008 Cameron 8.9 30.0049 -93.3433 Coastal - Stillwater Only

401-ILA-05-009 Cameron 8.9 29.9907 -93.4092 Coastal - Stillwater Only

401-ILA-05-010 Cameron 9.7 29.8904 -93.4020 Coastal - Stillwater Only

401-ILA-05-012 Cameron 12.6 29.7718 -93.4560 Coastal - Wave Height

401-ILA-05-016 Cameron 7.4 30.0108 -93.2274 Coastal - Stillwater Only

401-ILA-05-018 Cameron 3.8 29.9382 -93.0797 Coastal - Stillwater Only

401-ILA-05-019 Cameron 6.1 29.8943 -93.0796 Coastal - Stillwater Only

401-ILA-05-020 Cameron 8.7 29.8154 -93.1143 Coastal - Stillwater Only

401-ILA-05-026 Cameron 11.7 29.7648 -93.8810 Coastal - Stillwater Only

401-ILA-05-031 Cameron 7.0 30.0093 -93.1820 Coastal - Stillwater Only

401-ILA-05-032 Cameron 9.6 29.9886 -93.2663 Coastal - Stillwater Only

401-ILA-05-033 Cameron 9.0 29.8085 -93.1655 Coastal - Stillwater Only

401-ILA-05-034 Cameron 11.2 29.7871 -93.1314 Coastal - Wave Height

401-ILA-05-038 Cameron 8.0 29.7440 -92.8778 Coastal - Stillwater Only

401-ILA-05-040 Cameron 3.3 30.0318 -92.7513 Coastal - Stillwater Only

401-ILA-05-041 Cameron 3.0 30.0377 -92.6718 Coastal - Stillwater Only

401-ILA-05-042 Cameron 3.2 30.0224 -92.7688 Coastal - Stillwater Only

401-ILA-05-043 Cameron 2.3 30.0321 -92.7926 Coastal - Stillwater Only

401-ILA-05-044 Cameron 9.4 29.9837 -93.3750 Coastal - Stillwater Only

401-ILA-05-045 Cameron 8.7 29.9839 -93.4275 Coastal - Stillwater Only

401-ILA-02-002 Iberia 4.7 30.0617 -91.6086 Coastal - Stillwater Only

401-ILA-02-025 Iberia 5.2 30.0581 -91.6078 Coastal - Stillwater Only

401-ILA-02-026 Iberia 8.2 29.9519 -91.9849 Coastal - Stillwater Only

401-ILA-02-027 Iberia 6.4 29.9675 -91.9781 Coastal - Stillwater Only

401-ILA-02-028 Iberia 8.2 29.9472 -91.9840 Coastal - Stillwater Only

401-ILA-02-029 Iberia 8.5 29.9490 -91.9886 Coastal - Stillwater Only

401-ILA-02-030 Iberia 8.4 29.9146 -91.9045 Coastal - Stillwater Only

401-ILA-02-032 Iberia 7.2 29.9345 -91.8635 Coastal - Stillwater Only

401-ILA-02-034 Iberia 8.5 29.9497 -91.8359 Coastal - Stillwater Only

401-ILA-02-035 Iberia 8.1 29.9382 -91.8338 Coastal - Stillwater Only
E-20 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

E HIGH WATER MARKS

Summary of High Water Mark Survey Results

HWM ID Parish

Surveyed 

Elevation (feet) 

NAVD 88

Surveyed 

Latitude

Surveyed 

Longitude Flood Type

401-ILA-02-038 Iberia 8.9 29.8265 -91.8081 Coastal - Stillwater Only

401-ILA-02-039 Iberia 5.1 29.9145 -91.6622 Coastal - Stillwater Only

401-ILA-02-040 Iberia 5.3 29.9789 -91.7539 Coastal - Stillwater Only

401-ILA-02-041 Iberia 5.5 30.0111 -91.7433 Coastal - Stillwater Only

401-ILA-02-042 Iberia 4.5 30.0192 -91.6808 Coastal - Stillwater Only

401-ILA-02-043 Iberia 7.1 30.0569 -91.7400 Riverine - Hurricane

401-ILA-02-044 Iberia 5.3 30.0060 -91.8170 Coastal - Stillwater Only

401-ILA-02-045 Iberia 5.0 30.0161 -91.7739 Coastal - Stillwater Only

401-ILA-01-007 Iberville 5.9 30.2193 -91.3177 Coastal - Stillwater Only

401-ILA-01-018 Iberville 3.2 30.1348 -91.0932 Coastal - Stillwater Only

401-ILA-01-019 Iberville 4.3 30.1034 -91.1984 Coastal - Stillwater Only

401-ILA-01-020 Iberville 9.8 30.3214 -91.0209 Coastal - Stillwater Only

401-ILA-01-021 Iberville 3.3 30.1264 -91.2761 Coastal - Stillwater Only

401-ILA-01-022 Iberville 5.1 30.1502 -91.3278 Coastal - Stillwater Only

401-ILA-04-020 Jefferson 5.2 29.6533 -90.1063 Coastal - Stillwater Only

401-ILA-04-022 Jefferson 4.7 29.8851 -90.1623 Coastal - Stillwater Only

401-ILA-04-023 Jefferson 4.8 30.0420 -90.2354 Coastal - Stillwater Only

401-ILA-04-025 Jefferson 5.3 30.0214 -90.1432 Coastal - Stillwater Only

401-ILA-06-001 Jefferson 4.9 29.2377 -89.9923 Coastal - Stillwater Only

401-ILA-06-002 Jefferson 4.9 29.2626 -89.9621 Coastal - Stillwater Only

401-ILA-06-004 Jefferson 4.7 29.2256 -90.0070 Coastal - Stillwater Only

401-ILA-06-005 Jefferson 5.1 29.2165 -90.0254 Coastal - Stillwater Only

401-ILA-06-006 Jefferson 6.1 29.2037 -90.0398 Coastal - Wave Height

401-ILA-02-010 Jefferson Davis 3.3 30.0727 -92.6594 Coastal - Stillwater Only

401-ILA-05-001 Jefferson Davis 4.0 30.0733 -92.6607 Coastal - Stillwater Only

401-ILA-05-002 Jefferson Davis 3.8 30.0752 -92.6771 Coastal - Stillwater Only

401-ILA-05-003 Jefferson Davis 3.3 30.0570 -92.7194 Coastal - Stillwater Only

401-ILA-05-004 Jefferson Davis 3.6 30.0694 -92.8842 Coastal - Stillwater Only

401-ILA-05-023 Jefferson Davis 3.5 30.1376 -92.8864 Coastal - Stillwater Only

401-ILA-02-004 Lafayette 8.0 30.2192 -91.9559 Coastal - Stillwater Only

401-ILA-06-008 Lafourche 7.6 29.1555 -90.1834 Coastal - Stillwater Only

401-ILA-06-009 Lafourche 8.3 29.1254 -90.1969 Coastal - Stillwater Only

401-ILA-06-010 Lafourche 8.0 29.1577 -90.1791 Coastal - Stillwater Only

401-ILA-06-011 Lafourche 7.0 29.2112 -90.2198 Coastal - Stillwater Only

401-ILA-06-013 Lafourche 6.7 29.2359 -90.2104 Coastal - Stillwater Only

401-ILA-06-014 Lafourche 5.8 29.2567 -90.2139 Coastal - Stillwater Only

401-ILA-06-016 Lafourche 6.2 29.3416 -90.2469 Coastal - Wave Height

401-ILA-06-017 Lafourche 4.4 29.5892 -90.3702 Coastal - Stillwater Only

401-ILA-06-018 Lafourche 4.4 29.5827 -90.3748 Coastal - Stillwater Only

401-ILA-06-019 Lafourche 4.3 29.5574 -90.3890 Coastal - Stillwater Only

401-ILA-06-020 Lafourche 3.9 29.5527 -90.5346 Coastal - Stillwater Only

401-ILA-01-004 Livingston 7.2 30.3268 -90.8233 Riverine - Hurricane

401-ILA-01-005 Livingston 4.4 30.2749 -90.7788 Coastal - Stillwater Only

401-ILA-07-024 Livingston 3.3 30.4335 -90.5472 Coastal - Stillwater Only

401-ILA-07-026 Livingston 4.0 30.3766 -90.5372 Coastal - Stillwater Only

401-ILA-07-028 Livingston 4.6 30.2618 -90.7128 Coastal - Stillwater Only

401-ILA-07-029 Livingston 4.0 30.2838 -90.7085 Coastal - Stillwater Only

401-ILA-07-030 Livingston 4.5 30.2732 -90.7105 Coastal - Stillwater Only

401-ILA-07-031 Livingston 4.4 30.2668 -90.7289 Coastal - Stillwater Only

401-ILA-07-032 Livingston 4.4 30.2754 -90.7387 Coastal - Stillwater Only

401-ILA-07-033 Livingston 3.7 30.2610 -90.7637 Coastal - Stillwater Only

401-ILA-07-034 Livingston 4.5 30.2639 -90.6419 Coastal - Stillwater Only
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT E-21

HIGH WATER MARKS E

Summary of High Water Mark Survey Results

HWM ID Parish

Surveyed 

Elevation (feet) 

NAVD 88

Surveyed 

Latitude

Surveyed 

Longitude Flood Type

401-ILA-04-001 Plaquemines 3.7 29.6355 -89.9527 Coastal - Stillwater Only

401-ILA-04-002 Plaquemines 7.5 29.3540 -89.5359 Coastal - Wave Height

401-ILA-04-003 Plaquemines 6.4 29.2212 -89.3943 Coastal - Wave Height

401-ILA-04-004 Plaquemines 4.1 29.6990 -89.9913 Coastal - Stillwater Only

401-ILA-04-005 Plaquemines 3.6 29.6481 -89.9629 Coastal - Stillwater Only

401-ILA-04-006 Plaquemines 4.3 29.6023 -89.8784 Coastal - Stillwater Only

401-ILA-04-008 Plaquemines 6.2 29.4169 -89.6167 Coastal - Stillwater Only

401-ILA-04-010 Plaquemines 10.9 29.5861 -89.7972 Coastal - Stillwater Only

401-ILA-04-011 Plaquemines 8.1 29.6359 -89.9056 Coastal - Stillwater Only

401-ILA-04-012 Plaquemines 8.4 29.7426 -89.9872 Coastal - Stillwater Only

401-ILA-04-013 Plaquemines 8.2 29.6484 -89.9357 Coastal - Stillwater Only

401-ILA-04-014 Plaquemines 9.0 29.8603 -89.9073 Coastal - Stillwater Only

401-ILA-04-019 Plaquemines 5.2 29.8363 -90.0456 Coastal - Stillwater Only

401-ILA-04-016 St. Bernard 9.4 29.8199 -89.6112 Coastal - Stillwater Only

401-ILA-04-017 St. Bernard 8.8 29.8408 -89.7561 Coastal - Stillwater Only

401-ILA-06-021 St. Charles 3.4 29.7891 -90.4204 Coastal - Stillwater Only

401-ILA-06-022 St. Charles 3.5 29.7824 -90.4048 Coastal - Stillwater Only

401-ILA-06-024 St. Charles 2.7 29.8737 -90.4489 Coastal - Stillwater Only

401-ILA-06-025 St. Charles 2.7 29.8625 -90.4545 Coastal - Stillwater Only

401-ILA-01-001 St. James 3.7 30.1018 -90.7349 Coastal - Stillwater Only

401-ILA-01-002 St. James 3.3 30.0691 -90.7499 Coastal - Stillwater Only

401-ILA-01-013 St. James 3.4 30.0566 -90.7116 Coastal - Stillwater Only

401-ILA-01-014 St. James 3.3 30.0561 -90.7110 Coastal - Stillwater Only

401-ILA-01-015 St. James 2.5 29.9224 -90.6720 Coastal - Stillwater Only

401-ILA-01-016 St. James 2.4 29.9539 -90.6920 Coastal - Stillwater Only

401-ILA-01-017 St. James 2.2 29.9114 -90.7288 Coastal - Stillwater Only

401-ILA-01-008 St. John The 

Baptist 2.6 29.9199 -90.6221 Coastal - Stillwater Only

401-ILA-06-026 St. John The 

Baptist 4.6 30.0936 -90.4379 Coastal - Stillwater Only

401-ILA-06-027 St. John The 

Baptist 4.9 30.0884 -90.4420 Coastal - Stillwater Only

401-ILA-06-028 St. John The 

Baptist 4.7 30.0859 -90.4469 Coastal - Stillwater Only

401-ILA-06-029 St. John The 

Baptist 4.7 30.0910 -90.4597 Coastal - Stillwater Only

401-ILA-06-030 St. John The 

Baptist 4.8 30.0940 -90.4692 Coastal - Stillwater Only

401-ILA-06-031 St. John The 

Baptist 4.7 30.1062 -90.4983 Coastal - Stillwater Only

401-ILA-06-033 St. John The 

Baptist 3.6 30.1899 -90.4385 Coastal - Stillwater Only

401-ILA-06-034 St. John The 

Baptist 7.3 30.1067 -90.4229 Coastal - Wave Height

401-ILA-06-035 St. John The 

Baptist 4.6 30.0958 -90.4370 Coastal - Stillwater Only

401-ILA-06-036 St. John The 

Baptist 4.5 30.0608 -90.4393 Coastal - Stillwater Only

401-ILA-06-037 St. John The 

Baptist 4.2 30.0606 -90.4344 Coastal - Stillwater Only

401-ILA-06-038 St. John The 

Baptist 4.1 30.0600 -90.4333 Coastal - Stillwater Only
E-22 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

E HIGH WATER MARKS

Summary of High Water Mark Survey Results

HWM ID Parish

Surveyed 

Elevation (feet) 

NAVD 88

Surveyed 

Latitude

Surveyed 

Longitude Flood Type

401-ILA-06-040 St. John The 

Baptist 4.5 30.0802 -90.4611 Coastal - Stillwater Only

401-ILA-06-041 St. John The 

Baptist 4.3 30.0779 -90.5525 Coastal - Stillwater Only

401-ILA-06-042 St. John The 

Baptist 3.9 30.0785 -90.5459 Coastal - Stillwater Only

401-ILA-06-043 St. John The 

Baptist 4.0 30.0844 -90.5134 Coastal - Stillwater Only

401-ILA-02-014 St. Martin 8.4 30.3243 -91.7900 Coastal - Stillwater Only

401-ILA-02-017 St. Martin 7.4 30.3053 -91.7536 Coastal - Stillwater Only

401-ILA-02-018 St. Martin 7.2 30.2914 -91.7452 Coastal - Stillwater Only

401-ILA-02-021 St. Martin 5.3 30.2180 -91.6979 Coastal - Stillwater Only

401-ILA-02-022 St. Martin 5.5 30.1758 -91.6908 Coastal - Stillwater Only

401-ILA-03-001 St. Martin 3.0 29.8158 -91.1033 Coastal - Stillwater Only

401-ILA-03-003 St. Martin 9.3 29.8557 -91.1980 Coastal - Stillwater Only

401-ILA-03-004 St. Martin 3.1 29.9083 -91.2165 Coastal - Stillwater Only

401-ILA-03-009 St. Martin 2.6 29.7679 -91.1653 Coastal - Stillwater Only

401-ILA-03-010 St. Martin 8.0 29.7640 -91.1758 Coastal - Stillwater Only

401-ILA-03-011 St. Martin 9.7 29.9027 -91.2134 Coastal - Stillwater Only

401-ILA-02-036 St. Mary 9.3 29.7342 -91.8523 Coastal - Stillwater Only

401-ILA-02-037 St. Mary 10.6 29.7143 -91.8769 Coastal - Stillwater Only

401-ILA-03-056 St. Mary 7.3 29.6896 -91.0997 Coastal - Stillwater Only

401-ILA-03-057 St. Mary 6.7 29.6870 -91.1887 Coastal - Stillwater Only

401-ILA-03-058 St. Mary 4.2 29.6828 -91.1923 Coastal - Stillwater Only

401-ILA-03-059 St. Mary 6.9 29.6954 -91.2104 Coastal - Stillwater Only

401-ILA-03-060 St. Mary 6.8 29.6934 -91.2162 Coastal - Stillwater Only

401-ILA-03-061 St. Mary 7.4 29.6854 -91.2188 Coastal - Stillwater Only

401-ILA-03-062 St. Mary 6.7 29.9021 -91.5135 Coastal - Stillwater Only

401-ILA-03-063 St. Mary 4.7 29.8795 -91.4544 Coastal - Stillwater Only

401-ILA-03-064 St. Mary 9.7 29.7644 -91.3940 Coastal - Stillwater Only

401-ILA-03-065 St. Mary 4.8 29.7585 -91.4078 Coastal - Stillwater Only

401-ILA-03-066 St. Mary 5.1 29.7104 -91.3819 Coastal - Stillwater Only

401-ILA-03-067 St. Mary 6.4 29.7010 -91.3711 Coastal - Stillwater Only

401-ILA-03-068 St. Mary 5.1 29.7622 -91.4193 Coastal - Stillwater Only

401-ILA-08-029 St. Mary 10.2 29.7127 -91.8771 Coastal - Stillwater Only

401-ILA-08-030 St. Mary 8.7 29.7711 -91.7848 Coastal - Stillwater Only

401-ILA-08-032 St. Mary 6.0 29.7882 -91.5190 Coastal - Stillwater Only

401-ILA-08-034 St. Mary 6.9 29.7867 -91.5173 Coastal - Stillwater Only

401-ILA-08-037 St. Mary 6.3 29.8291 -91.5664 Coastal - Stillwater Only

401-ILA-08-038 St. Mary 4.4 29.8870 -91.5227 Coastal - Stillwater Only

401-ILA-08-039 St. Mary 4.0 29.8900 -91.5246 Coastal - Stillwater Only

401-ILA-08-040 St. Mary 5.5 29.8407 -91.4548 Coastal - Stillwater Only

401-ILA-08-042 St. Mary 4.7 29.8795 -91.5858 Coastal - Stillwater Only

401-ILA-08-044 St. Mary 8.1 29.5590 -91.5251 Coastal - Stillwater Only

401-ILA-08-045 St. Mary 6.2 29.6017 -91.5247 Coastal - Stillwater Only

401-ILA-08-048 St. Mary 5.1 29.7874 -91.4953 Coastal - Stillwater Only

401-ILA-08-049 St. Mary 6.7 29.7976 -91.4968 Coastal - Stillwater Only

401-ILA-08-050 St. Mary 5.3 29.7720 -91.4814 Coastal - Stillwater Only

401-ILA-07-001 St. Tammany 6.6 30.4083 -90.1420 Coastal - Stillwater Only

401-ILA-07-002 St. Tammany 6.3 30.3449 -90.0534 Coastal - Stillwater Only

401-ILA-07-004 St. Tammany 6.6 30.3657 -90.0959 Coastal - Stillwater Only

401-ILA-07-005 St. Tammany 6.7 30.3526 -90.0673 Coastal - Stillwater Only
HURRICANE IKE IN TEXAS and Louisiana MITIGATION ASSESSMENT TEAM REPORT E-23

HIGH WATER MARKS E

Summary of High Water Mark Survey Results

HWM ID Parish

Surveyed 

Elevation (feet) 

NAVD 88

Surveyed 

Latitude

Surveyed 

Longitude Flood Type

401-ILA-07-006 St. Tammany 4.7 30.3291 -90.0044 Coastal - Stillwater Only

401-ILA-07-007 St. Tammany 5.5 30.2651 -89.9565 Coastal - Stillwater Only

401-ILA-07-008 St. Tammany 4.6 30.2912 -89.9279 Coastal - Stillwater Only

401-ILA-07-009 St. Tammany 4.9 30.2841 -89.9170 Coastal - Stillwater Only

401-ILA-07-012 St. Tammany 4.3 30.2795 -89.7844 Coastal - Stillwater Only

401-ILA-07-013 St. Tammany 5.2 30.2611 -89.8033 Coastal - Stillwater Only

401-ILA-07-014 St. Tammany 5.1 30.2346 -89.8553 Coastal - Stillwater Only

401-ILA-07-016 St. Tammany 4.8 30.1853 -89.7572 Coastal - Stillwater Only

401-ILA-07-017 St. Tammany 6.5 30.3943 -90.1203 Coastal - Stillwater Only

401-ILA-07-018 St. Tammany 6.6 30.4027 -90.1561 Coastal - Stillwater Only

401-ILA-07-019 St. Tammany 6.6 30.3977 -90.1562 Coastal - Stillwater Only

401-ILA-07-021 Tangipahoa 5.2 30.2897 -90.4014 Coastal - Stillwater Only

401-ILA-03-015 Terrebonne 5.3 29.5853 -90.6774 Coastal - Stillwater Only

401-ILA-03-016 Terrebonne 6.0 29.5545 -90.6592 Coastal - Stillwater Only

401-ILA-03-020 Terrebonne 6.0 29.5191 -90.6753 Coastal - Stillwater Only

401-ILA-03-022 Terrebonne 6.4 29.4822 -90.6983 Coastal - Stillwater Only

401-ILA-03-023 Terrebonne 7.1 29.4254 -90.7020 Coastal - Stillwater Only

401-ILA-03-024 Terrebonne 7.0 29.3946 -90.7120 Coastal - Stillwater Only

401-ILA-03-025 Terrebonne 6.9 29.3689 -90.7231 Coastal - Stillwater Only

401-ILA-03-026 Terrebonne 7.6 29.2532 -90.6600 Coastal - Stillwater Only

401-ILA-03-027 Terrebonne 7.7 29.2770 -90.6440 Coastal - Stillwater Only

401-ILA-03-028 Terrebonne 7.3 29.3047 -90.6480 Coastal - Stillwater Only

401-ILA-03-029 Terrebonne 6.9 29.3838 -90.6197 Coastal - Stillwater Only

401-ILA-03-030 Terrebonne 3.3 29.4737 -90.5575 Coastal - Stillwater Only

401-ILA-03-031 Terrebonne 3.9 29.4740 -90.5532 Coastal - Stillwater Only

401-ILA-03-032 Terrebonne 4.9 29.4804 -90.5517 Coastal - Stillwater Only

401-ILA-03-033 Terrebonne 8.0 29.3857 -90.5882 Coastal - Wave Height

401-ILA-03-034 Terrebonne 4.6 29.4992 -90.5512 Coastal - Stillwater Only

401-ILA-03-035 Terrebonne 7.8 29.3985 -90.4884 Coastal - Wave Height

401-ILA-03-037 Terrebonne 7.5 29.3986 -90.4888 Coastal - Stillwater Only

401-ILA-03-040 Terrebonne 7.1 29.4394 -90.4611 Coastal - Stillwater Only

401-ILA-03-041 Terrebonne 5.1 29.4905 -90.5198 Coastal - Stillwater Only

401-ILA-03-042 Terrebonne 5.5 29.5133 -90.5960 Coastal - Stillwater Only

401-ILA-03-043 Terrebonne 5.5 29.5161 -90.5978 Coastal - Stillwater Only

401-ILA-03-044 Terrebonne 4.7 29.5370 -90.7144 Coastal - Stillwater Only

401-ILA-03-045 Terrebonne 3.9 29.5447 -90.7234 Coastal - Stillwater Only

401-ILA-03-046 Terrebonne 3.9 29.6050 -90.7050 Coastal - Stillwater Only

401-ILA-03-048 Terrebonne 4.0 29.5692 -90.7252 Coastal - Stillwater Only

401-ILA-03-049 Terrebonne 5.9 29.4282 -90.7644 Coastal - Stillwater Only

401-ILA-03-050 Terrebonne 5.7 29.4169 -90.7760 Coastal - Stillwater Only

401-ILA-03-051 Terrebonne 6.9 29.3340 -90.8483 Coastal - Wave Height

401-ILA-03-052 Terrebonne 5.7 29.3360 -90.8424 Coastal - Stillwater Only

401-ILA-03-053 Terrebonne 3.8 29.6163 -90.9022 Coastal - Stillwater Only

401-ILA-03-054 Terrebonne 3.9 29.6245 -90.9111 Coastal - Stillwater Only

401-ILA-05-039 Vermilion 4.0 30.0435 -92.7060 Coastal - Stillwater Only

401-ILA-08-002 Vermilion 9.4 29.7939 -92.1449 Coastal - Stillwater Only

401-ILA-08-004 Vermilion 8.0 29.9350 -92.1494 Coastal - Stillwater Only

401-ILA-08-005 Vermilion 8.6 29.8847 -92.1245 Coastal - Stillwater Only

401-ILA-08-006 Vermilion 8.3 29.9835 -92.1360 Coastal - Stillwater Only

401-ILA-08-007 Vermilion 5.4 29.8428 -92.1810 Coastal - Stillwater Only

401-ILA-08-008 Vermilion 7.4 29.8464 -92.2756 Coastal - Stillwater Only

401-ILA-08-009 Vermilion 5.9 29.8316 -92.3061 Coastal - Stillwater Only
E-24 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IKE IN TEXAS and Louisiana

E HIGH WATER MARKS

Summary of High Water Mark Survey Results

HWM ID Parish

Surveyed 

Elevation (feet) 

NAVD 88

Surveyed 

Latitude

Surveyed 

Longitude Flood Type

401-ILA-08-011 Vermilion 7.9 29.6573 -92.3693 Coastal - Wave Height

401-ILA-08-012 Vermilion 7.8 29.6468 -92.4342 Coastal - Wave Height

401-ILA-08-015 Vermilion 6.1 29.8386 -92.3282 Coastal - Stillwater Only

401-ILA-08-016 Vermilion 8.3 29.6308 -92.3820 Coastal - Wave Height

401-ILA-08-017 Vermilion 8.1 29.9749 -92.1395 Coastal - Stillwater Only

401-ILA-08-018 Vermilion 3.5 30.0413 -92.7226 Coastal - Stillwater Only

401-ILA-08-019 Vermilion 3.3 30.0713 -92.6571 Coastal - Stillwater Only

401-ILA-08-020 Vermilion 3.6 30.1004 -92.5321 Coastal - Stillwater Only

401-ILA-08-021 Vermilion 3.2 29.9192 -92.5138 Coastal - Stillwater Only

401-ILA-08-022 Vermilion 2.8 29.9782 -92.4621 Coastal - Stillwater Only

401-ILA-08-025 Vermilion 7.8 29.8825 -92.0378 Coastal - Stillwater Only

401-ILA-08-026 Vermilion 9.0 29.8770 -92.1269 Coastal - Stillwater Only

401-ILA-08-027 Vermilion 8.8 29.9751 -91.9940 Coastal - Stillwater Only
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