Mitigation Assessment Team Report

Hurricanes Irma and Maria 

in Puerto Rico

Building Performance, Observations, Recommendations, 

and Technical Guidance

FEMA P-2020 / October 2018 
Any opinions, findings, conclusions, or recommendations expressed in this publication do not necessarily reflect 

the views of FEMA. Additionally, neither FEMA nor any of its employees makes any warranty, expressed or implied, 

or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, 

product, or process included in this publication. Users or information from this publication assume all liability 

arising from such use.

All photographs and figures used in this report were taken by the Mitigation Assessment Team (MAT) or developed 

for this report unless stated otherwise.

Map imagery sources (unless otherwise noted in the report):

CariCOOS https://www.caricoos.org/

USGS https://www.usgs.gov/

Weather Flow http://weatherflow.com

NSF RAPID https://nsf.gov

NOAA https://storms.ngs.noaa.gov/
MITIGATION ASSESSMENT TEAM REPORT

Hurricanes Irma and Maria 

in Puerto Rico

Building Performance Observations,

Recommendations, and Technical Guidance

FEMA P-2020 / October 2018
Members of the Mitigation Assessment Team

Team Leaders

Daniel Bass, RA, CFM, FEMA HQ

Edward Laatsch, PE, FEMA HQ

Team Managers

Stuart Adams, EI, CFM, Stantec

Scott Tezak, PE, BSCP, Atkins

Team Members

Luis Aponte Bermúdez, PhD, PE Ancuta Lungu, FEMA HQ

Roberto Alsina, Diversity Professional Services, LLC Andrew Martin, CFM, FEMA Region II

Erin Ashley, PhD, LEED AP, Atkins Desidero Maldonado, PE, Atkins

Dana Bres, PE, Department of Housing and Urban Jeanine Neipert, FEMA HQ

Development Juan Nieves, EI, CFM, Dewberry

David Conrad, PE, Atkins John “Bud” Plisich, FEMA Region IV

Astrid Diaz, RA, ADV Architects Rebecca Quinn, CFM, RCQuinn Consulting, Inc.

Jason Fennell, PE, Forte & Tablada Shudipto Rahman, FEMA Region II

Jeff Gangai, CFM, Dewberry Audrey Rierson, JD, Federal Allliance for Safe Homes, Inc.

Julie Grauer, CFM, FEMA HQ Michael Rimoldi, CBO, CFM, Federal Alliance for Safe Homes, 

Matthew Holland, PE, CFM, Stantec Inc.

John Ingargiola, EI, CFM, CBO, FEMA HQ John Squerciati, PE, CFM, Dewberry

Marc Levitan, PhD, National Institute of Standards and Jonathan Westcott, PE, FEMA HQ

Technology

Ryan Littlewood, Stantec

Internal Support (STARR II)

Drone Support

Hayden Gower, Stantec

Formatting/Graphic Artists

Corina Coulas, Stantec

Alesia ZaGara, Stantec

GIS Specialist

Tim Ward, GISP, Stantec

Quality Control

Steve Kalaf, CFM, PMP, 

 Dewberry

Marc Pearson, Stantec

Technical Editor

Ryan Littlewood, Stantec
MITIGATION ASSESSMENT TEAM REPORT

In response to Hurricanes Irma and Maria, the Federal 

Emergency Management Agency (FEMA) deployed 

a Mitigation Assessment Team (MAT) to evaluate 

damage, document observations, and, based on 

these, offer conclusions and recommendations on the 

performance of buildings and other structures affected 

by wind forces, flooding, and other hazards due to the 

hurricanes. The MAT included FEMA Headquarters 

and Regional Office engineers, representatives from 

other Federal agencies, government officials from 

the Commonwealth of Puerto Rico, and experts from 

academia and the design and construction industries. 

The conclusions and recommendations in this report 

are intended to provide decision makers, designers, 

contractors, planners, code officials, industry groups, 

government officials, academia, homeowners, and 

business owners and operators with information and 

technical guidance that can be used to reduce future 

hurricane damage.

DEDICATION

The Puerto Rico Mitigation 

Assessment Team dedicates 

this report to the memory of 

the victims of Hurricanes 

Irma and Maria, and 

the families, friends, and 

communities suffering from 

their loss. The Mitigation 

Assessment Team hopes this 

report will help others avoid 

similar losses in the future.

HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT i

HURRICANES

IRMA AND MARIA

IN PUERTO RICO

MITIGATION ASSESSMENT TEAM REPORT

Executive Summary 

In September 2017, Hurricanes Irma and Maria significantly 

impacted Puerto Rico. 

Irma was a Category 5 hurricane when its eye passed within 30 miles (48 kilometers) of the Puerto 

Rican island of Culebra on September 6, 2017. Peak wind gust speeds in the Commonwealth of 

Puerto Rico were over 120 miles per hour (mph) (193 kilometers per hour [kph]) and over 10 

inches (25 centimeters) of rainfall was recorded. Thousands of buildings were damaged and over 

a million residents lost power. Just two weeks later, on September 20, while much of Puerto Rico 

was still recovering, Maria made landfall as a Category 4 hurricane. Preliminary peak wind gusts in 

Puerto Rico were over 140 mph (225 kph), over 35 inches (89 centimeters) of rainfall was recorded, 

and storm surge of over 6 feet (2 meters) was estimated. The hurricanes caused numerous deaths. 

Hundreds of thousands of buildings were damaged and the power grid failed, causing long-lasting 

interruptions to essential services. Most of the 3.7 million residents were left without power for 

months, and 95 percent of cellular sites were out of service, leading to complicated and protracted 

recovery efforts. 

Puerto Rico experienced high wind speeds throughout the Commonwealth during both storms, 

particularly on the islands of Culebra and Vieques and along the northeastern coast of the island 

of Puerto Rico. In some areas of the Commonwealth, wind speeds approached or exceeded the 

prescribed design wind speed requirements of 145 mph (233 kph) of the American Society of Civil 

Engineers (ASCE) standard, Minimum Design Loads and for Buildings and Other Structures 

(ASCE 7-05). This standard is referenced by the 2009 International Building Code (IBC©) and 

the 2009 International Residential Code (IRC©), which are the model codes legally adopted in the 

effective building code at the time of both storms, the 2011 Puerto Rico Building Code (PRBC).
ii MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

EXECUTIVE SUMMARY

Damage from storm surge and flooding was 

severe in some areas, while wind damage was 

widespread throughout the Commonwealth. 

Damage from wind-driven rain and other 

sources of water intrusion was significant 

across many building types, including critical 

facilities. High winds caused severe damage, 

particularly to informally constructed

buildings (broadly defined as those not 

permitted or not built to current building 

standards) and improperly anchored rooftop 

equipment.

Radar image of Hurricane Maria at 0950 UTC, September 20, 2017, just 

before landfall in Puerto Rico. Source: Pasch, Penny, and Berg (2018).

Past Disasters and Mitigation

Puerto Rico has a history of reacting to the 

impact of severe previous hurricanes by 

adopting hazard mitigation techniques to 

minimize future damage. Previous mitigation 

actions have included establishing or improving building codes and building code enforcement. 

This was a key recommendation of the Federal Emergency Management Agency (FEMA) Hurricane 

Georges Building Performance and Assessment Team (BPAT) Report and is recommended again in 

this report. 

On September 18, 1989, Hurricane Hugo made landfall in Puerto Rico as a Category 2 hurricane. 

Hugo caused severe damage to the infrastructure of Puerto Rico, with over thirty thousand people 

losing their homes. Eighty percent of wooden structures on Culebra and Vieques were destroyed. 

Property damage is estimated to have exceeded $1 billion in 1989 dollars1. Evidence of mitigation 

carried out in response to Hurricane Hugo, including the installation of frame connection hardware 

(hurricane clips) and other wind retrofits was later cited in the Hurricane Georges FEMA report.

On September 21, 1998, the Category 2 Hurricane Georges made landfall in Puerto Rico. Georges 

had devastating effects on an array of building types and infrastructure. In the aftermath of 

Georges, FEMA made observations and recommendations. Observations included a prevalence of 

informally constructed buildings. Poor implementation and enforcement of existing codes were 

cited as a major contributor to the heavy losses. Because Hurricane Georges’s winds were below 

design speeds for modern building codes, code-compliant construction would likely have proved 

much more hurricane-resistant than what was observed. Noting deficiencies in the building code, 

Puerto Rico adopted the 1997 Uniform Building Code (UBC) with local amendments following 

Georges. The 1997 UBC served as Puerto Rico’s Building Code until the 2009 IBC© was adopted in 

2011.

Additional mitigation efforts beyond the building code included a major reconstruction and hazard 

mitigation program after Hurricane Georges called the New Secure Housing Project (NSHP). This 

project, established in October 1998 by order of then-Governor Pedro Rosselló, had an “on-site 

component” that replaced vulnerable buildings at existing sites. Its “off-site component” involved 

1This is roughly $2 billion in inflation-adjusted September 2017 dollars.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT iii

EXECUTIVE SUMMARY

acquiring and removing damaged or destroyed 

homes in highly flood-, seismic-, and landslideprone sites, and replacing them at new sites. 

The NSHP built 1,647 housing units that were 

designed to the 1997 UBC, and these performed 

well during the recent hurricanes.

HURRICANE METRICS

Hurricane Irma

• Several deaths

• Skirted Puerto Rico as a Category 5 hurricane,

approaching within 30 miles (48 kilometers)

• Sustained winds in Puerto Rico 58 mph (93 kph)

• Maximum rainfall 10–15 inches (25–38 centimeters)

in 36 hours

• With $50 billion in damage, the fifth-costliest

hurricane in U.S. history

Hurricane Maria

• Numerous deaths

• Strong Category 4 hurricane at landfall in Puerto

Rico

• Sustained winds in Puerto Rico 155 mph (249 kph)

• Maximum rainfall 38 inches (96 centimeters) in 48

hours

• With $90 billion in damage, the third-costliest

hurricane in U.S. history

Mitigation Assessment Team

For over 30 years, FEMA has been conducting 

studies and assessments of the performance of 

the built environment after disasters of national 

significance. In these instances, FEMA deploys 

Mitigation Assessment Teams (MATs) to observe 

building performance and provide design and 

construction guidance to improve disaster 

resistance of the built environment in the 

affected area. MATs are composed of national 

and regional experts including academics, design 

professionals, FEMA engineers, representatives 

from standards development organizations, and 

other subject matter experts as needed for the 

event.

Following Hurricanes Irma and Maria, FEMA’s Building Science Branch, in coordination with 

Region II office and the Puerto Rico Joint Field Office (JFO), deployed a Preliminary MAT in 

October 2017. Observations from that team led to a full MAT deployment in December. The MAT 

consulted frequently with Commonwealth and municipal officials and resident subject matter experts 

during both deployments. Areas of focused observations included: building codes, standards and 

regulations; residential and low-rise buildings; schools, critical facilities, photovoltaic (PV) arrays, 

and solar water heaters. 

Assessment Observations

The MAT visited affected locations throughout Puerto Rico, including the islands of Culebra 

and Vieques, making observations on building performance. Initial mitigation topics from the 

MAT observations included rooftop equipment attachment, Coastal A Zone (CAZ) construction 

techniques, topographic wind-speed up effects, and hurricane sheltering considerations. These and 

other important topics were communicated to Commonwealth and municipal stakeholders, JFO 

staff, and the public in the form of six Recovery Advisories (Appendix D) and this MAT report. The 

key purpose of this report is to aid communities in rebuilding resiliently and improving the hazard 

resistance of existing and new buildings in Puerto Rico and throughout the rest of the United States 

and its territories. 
iv MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

EXECUTIVE SUMMARY

Recommendations

The MAT observed severe damage to residential and public buildings. Many homes in Puerto Rico 

are of informal construction, and the residential building stock is aging. The rate of flood insurance 

participation in the Commonwealth is limited. All these factors have negatively impacted many 

residents. Hurricanes Irma and Maria destroyed several hundred thousand homes and, with many 

homeowners not carrying flood insurance policies from the National Flood Insurance Program 

(NFIP), these residents’ ability to rebuild is uncertain.

This report provides many recommendations to assist in rebuilding a more resilient Puerto Rico, 

addressed respectively to the public, private, and nonprofit sectors. Three key recommendations 

follow:

Recommendation PR-3a. The Permits Management Office (OGPe2 ) should finalize 

adoption of the latest hazard-resistant building codes and standards. To enable new 

buildings and those that have been substantially damaged or will be substantially 

improved to better resist the impacts of hurricanes, floods, and seismic events, the latest 

edition of the building code and reference standards should be considered for adoption. 

OGPe should review the entire International Codes series (I-Codes) and adopt those 

that are relevant for the Commonwealth. In addition, Puerto Rico should consider local 

amendments to ensure that the hazard-resistant provisions are not weakened and that 

local conditions are accounted for. 

Recommendation PR-9a. FEMA should consider working with the Insurance Institute 

for Business & Home Safety to conduct a review of private flood insurance policies for 

equivalency and effectiveness. Private flood insurance can offer different protections 

than NFIP policies. Because Puerto Rico’s reliance on private insurance is unique in 

the U.S., a study is warranted after this event to assess the efficacy of private insurance 

on homeowners’ ability to rebuild more quickly while reducing the burden on U.S. 

taxpayers. 

Recommendation PR-35a. Puerto Rico should require storm shelters to be provided 

in all new Group E Occupancy buildings. Storm shelters provide buildings or portions 

with life-safety protection from high wind events such as hurricanes. Puerto Rico should 

create a local amendment to the PRBC to require that any new facilities constructed 

for Educational Group E Occupancies with an aggregate occupant load of 50 or more 

(including public and private schools, but excluding Group E day-care facilities or Group 

E occupancies3 accessory to places of religious worship), 911 call stations, emergency 

operations centers and fire, rescue, ambulance and police stations comply with IBC© 

table 1604.5 as a Risk Category IV structure and be provided with a storm shelter 

constructed in accordance with ICC 500©. In addition, OGPe and PRDOH should keep 

a record of all ICC©-compliant community shelters in the Commonwealth.

2The Permits Management Office (Oficina de Gerencia de Permisos) is commonly referred to by its Spanish acronym, OGPe.

3The 2018 IBC defines eight classifications of occupancy and use, with varying levels of hazard and risk. The 2018 IBC© defines an Educational 

Group E occupancy as including “among others, the use of a building or structure, or a portion thereof, by six or more persons at any one time for 

educational purposes through the 12th grade (ICC© 2018, 305.1). 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT v

HURRICANES

IRMA AND MARIA

IN PUERTO RICO

MITIGATION ASSESSMENT TEAM REPORT

Contents

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

Past Disasters and Mitigation ......................................................................................................ii

Mitigation Assessment Team ......................................................................................................iii

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

 Recommendations ....................................................................................................................... iv

Contents ...................................................................................................................................................v

 Appendices ...................................................................................................................................x

List of Figures ..............................................................................................................................xi

List of Tables ..........................................................................................................................xxviii

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

1.1 Organization of the Report ...................................................................................................... 1-2

1.2 Overview of Recent Hurricanes ............................................................................................... 1-2

1.2.1 Hurricane Irma ............................................................................................................. 1-2

1.2.2 Hurricane Maria ...........................................................................................................1-7

1.3 History of Previous Hurricanes and Mitigation .................................................................... 1-12

1.3.1 Hurricane Hugo ...........................................................................................................1-12

1.3.2 Hurricane Georges ......................................................................................................1-13

1.3.2.1 BPAT Mitigation Recommendations ..........................................................1-16

1.3.2.2 Project Impact Culebra ................................................................................1-18

1.3.2.3 New Secure Housing Program ....................................................................1-18
vi MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

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 1.3.3 Other FEMA Hazard Mitigation
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT vii

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Performance of Low-Rise Buildings ............................................................................................ 3-1

3.1 Summary of Building Performance .........................................................................................3-2

3.2 Performance Relative to Flood .................................................................................................3-8

 3.2.1 Coastal Flood Impacts .................................................................................................. 3-9

3.2.1.1 Coastal Flood Forces ..................................................................................... 3-9

3.2.1.2 Coastal Erosion ............................................................................................3-17

 3.2.2 Inland Flood Impacts ................................................................................................. 3-21

3.2.2.1 Building Performance ................................................................................ 3-21

3.2.2.2 Foundation Performance ........................................................................... 3-25

3.2.2.3 Mechanical, Electrical, and Plumbing System Performance ................... 3-25

3.3 Performance Relative to Wind ...............................................................................................3-28

 3.3.1 Main Wind Force Resisting System ............................................................................. 3-28

3.3.1.1 One- and Two-Family Residential Buildings .............................................3-30

3.3.1.2 Low-Rise, Multi-Family Residential Buildings .......................................... 3-35

 3.3.2 Windows ....................................................................................................................... 3-35

3.3.2.1 Jalousie Windows ......................................................................................... 3-36

3.3.2.2 Glazed Windows .......................................................................................... 3-37

3.3.2.3 Opening Protection .................................................................................... 3-39

 3.3.3 Roof Systems ...............................................................................................................3-43

3.3.3.1 Metal Roof Covering ...................................................................................3-44

3.3.3.2 Tile Roof Covering ......................................................................................3-46

 3.3.4 Topographic Effects on Wind Forces ........................................................................3-48

3.4 Performance Relative to Geology (Landslide) ......................................................................3-52

3.5 Successes Due to Previous Mitigation ...................................................................................3-58

 3.5.1 Successes Related to Hurricanes Hugo and Marilyn Programs ..............................3-58

 3.5.2 Floodplain Acquisitions in Villa Monseratte .............................................................3-60

 3.5.3 Successes Related to Hurricane Georges MAT Recommendations .......................3-60

Performance of Schools and Shelters ......................................................................................... 4-1

4.1 Summary of School and Shelter Performance ........................................................................ 4-1

4.2 Effect of Siting on the Performance of School Buildings ......................................................4-3

4.3 Performance Relative to Flood .................................................................................................4-6
viii MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

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 4.3.1 Elevation and Freeboard
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT ix

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 5.2.1 Performance Relative to Flood
x MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

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6.2.3.3 Zimmer Biomet Facility .............................................................................. 6-25

Conclusions and Recommendations ...............................................................................................7-1

7.1 Summary of Conclusions and Recommendations .................................................................. 7-1

7.2 General Conclusions ................................................................................................................7-3

7.3 Building Codes, Standards, and Regulations..........................................................................7-4

 7.3.1 PRBC .............................................................................................................................. 7-5

 7.3.2 Planning Board, OGPe, and Autonomous Municipalities ......................................... 7-6

 7.3.3 Planning Regulation 13 ...............................................................................................7-10

 7.3.4 NFIP ..............................................................................................................................7-10

 7.3.5 FEMA Technical Publications and Guidance ............................................................7-11

7.4 Planning and Programmatic Mitigation ............................................................................... 7-13

7.5 General Building Considerations .......................................................................................... 7-13

7.6 Residential and Low-Rise Buildings ....................................................................................... 7-16

7.7 Schools, Hospitals, Public Buildings, and Other Mid-Rise Buildings ................................ 7-18

7.8 Shelters ..................................................................................................................................... 7-20

7.9 Siting ........................................................................................................................................ 7-22

7.10 Solar Heating and PV Systems ................................................................................................ 7-23

7.11 Flood-Damage-Resistant Materials ........................................................................................ 7-26

7.12 Summary of Conclusions and Recommendations ................................................................ 7-26

Appendices

Appendix A. Acknowledgments ..........................................................................................................A-1

Appendix B. Bibliography ...................................................................................................................B-1

Appendix C. Acronyms ........................................................................................................................C-1

Appendix D. Recovery Advisories for Hurricanes Irma and Maria in Puerto Rico ........................ D-1
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT xi

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List of Figures

Figure 1-1: Top, Hurricane Irma’s track; bottom, Hurricane Irma wind speed radii for 39, 

58, 74 mph (63, 93, 119 kph) winds. Modified from Cangialosi, Latto, and Berg 

(2018)................................................................................................................................ 1-4

Figure 1-2: Preliminary peak wind gust map for Hurricane Irma with track (blue line). 

Estimated 3-second gust wind speeds (mph) at 33 feet (10 meters) above 

ground for flat open terrain from ARA model fit to surface level observations. 

The model used smoothed National Hurricane Center storm track and central 

pressure data through Forecast/Advisory 52 at 03:00 UTC on September 12, 2017. .. 1-5

Figure 1-3: Peak sustained and gust wind speeds measured during Hurricane Irma. Data 

source: Cangialosi, Latto, and Berg (2018). ................................................................... 1-5

Figure 1-4: Estimated storm surge inundation (feet above mean sea level) for Hurricane 

Irma. Data source: Coastal Emergency Risks Assessment (2017). ................................ 1-6

Figure 1-5: Estimated rainfall total from Hurricane Irma. ............................................................. 1-6

Figure 1-6: Top, Hurricane Maria’s track, bottom, Hurricane Maria wind speed radii for 

39, 58, 75 mph (63, 93, 118 kph) winds. Modified from Pasch, Penny, and Berg 

(2018)................................................................................................................................ 1-8

Figure 1-7: Preliminary peak wind gust map for Hurricane Maria with track (blue line). 

Estimated 3-second gust wind speeds (mph) at 33 feet (10 meters) above 

ground for flat open terrain from ARA model fit to surface level observations. 

The model used smoothed National Hurricane Center storm track and central 

pressure data through Intermediate Advisory 41A at 12:00 UTC on September 

26, 2017. ........................................................................................................................... 1-9

Figure 1-8: Peak sustained and gust wind speeds measured during Hurricane Maria. Data 

source: Pasch, Penny, and Berg (2018). .......................................................................... 1-9

Figure 1-9: Estimated storm surge inundation (feet above mean sea level) for Hurricane 

Maria. Data source: Coastal Emergency Risks Assessment (2017). .............................1-10

Figure 1-10: Estimated rainfall total from Hurricane Maria (National Weather Service 2017). ...1-11

Figure 1-11: Hurricanes in Puerto Rico since 1851, color-coded by Saffir-Simpson 

hurricane wind speed category. Data source: NOAA (2018). ......................................1-12

Figure 1-12: FEMA BPAT Report for Hurricane Georges (FEMA 339 1999). .................................1-13

Figure 1-13: Examples of observed damage by the BPAT after Hurricane Georges in 1998. 

Source: (FEMA, 1999a). .................................................................................................1-14
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Figure 1-14: Frame connection hardware (hurricane clips) installed in a wood-framed 

house on Culebra. Source: FEMA (1999a, 52). .............................................................1-15

Figure 1-15: Example of damage to floodplain development observed by BPAT after 

Hurricane Georges in 1998. Source: FEMA (1999a, 30). ............................................1-16

Figure 1-16: Cover of the 1997 UBC, adopted by Puerto Rico after Hurricane Georges. ..............1-18

Figure 1-17: Locations of New Secure Housing Program Communities. ........................................1-19

Figure 2-1: Timeline for the Puerto Rico Building Code ................................................................ 2-2

Figure 3-1: Elevated concrete house in Punta Santiago that performed well. ............................... 3-3

Figure 3-2: Elevated house (left) and non-elevated house (right) in northern Mayaguez, 

Zone AE. ........................................................................................................................... 3-9

Figure 3-3: Apartment building in Punta Santiago, Humacao, elevated on fill. Adjacent 

buildings experienced significant damage from coastal storm surge. Effective 

FIRM: Zone AE. Advisory Data: CAZ. ......................................................................... 3-10

Figure 3-4: Top, 2005 superseded FIRM for an area in Punta Santiago; bottom, a portion 

of the 2009 effective FIRM. The apartment building shown in Figure 3-2 is in 

the VE Zone on the 2005 FIRM and AE Zone on the 2009 effective FIRM. ............ 3-11

Figure 3-5: A portion of the Advisory Data for an area in Punta Santiago. The apartment 

building shown in Figure 3-3 is shown in the CAZ in the Advisory Data. ................. 3-12

Figure 3-6: Poorly constructed elevated buildings in Punta Santiago. ......................................... 3-12

Figure 3-7: Left, storm-induced beach erosion in Punta Santiago. Right, the location 

(red box) of the apartment building shown in Figure 3-3 overlaps a region of 

Hurricane Maria beach erosion (yellow shading) identified in the Advisory Data. . 3-13

Figure 3-8: Left, concrete house in Fajardo subject to 1.5-foot (0.5-meter) wave heights. 

Current FIRM and Advisory Data: VE Zone. Right, elevated beachfront house 

in Punta Santiago, Humacao subjected to wave heights greater than 1.5 feet 

(0.5 meters). Current FIRM: AE Zone. Advisory Data: CAZ. ......................................3-14

Figure 3-9: Left, an elevated wood-framed house in Punta Santiago was destroyed, right, 

an elevated concrete house withstood wind and coastal wave forces. Current 

FIRM: VE Zone. ..............................................................................................................3-14

Figure 3-10: Left, house in Playa Cortada subject to damaging storm surge and waves; 

right, high water mark from storm surge 2.2 feet (0.66 meters) above the floor. ..... 3-15

Figure 3-11: Shoreline at Playa Cortada where sand, rock, and broken-up debris covered 

the ground. .................................................................................................................... 3-16
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Figure 3-12: A portion of the 2009 current effective FIRM for Playa Cortada. ............................. 3-16

Figure 3-13: An example of projected future shoreline positions after long-term coastal 

erosion, Playa Cortada, Santa Isabel. ............................................................................3-17

Figure 3-14: Multi-story residence in Rincón that partially collapsed due to coastal erosion. ...... 3-18

Figure 3-15: Aerial photographs of a beach in Rincón showing the residence pictured 

in Figure 3-14 (red box). Left, 1930s aerial showing wide natural beach 

with no development. Source: López Marrero, et al. (2017). Center, preIrma and -Maria aerial. Source: ESRI, Digital Globe, GeoEye, Earthstar 

Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS 

User Community. Right, post-Irma and -Maria aerial showing storm-induced 

erosion of the narrow beach. Source: NOAA 2017. ..................................................... 3-20

Figure 3-16: An example of projected future shoreline positions after long-term coastal 

erosion, showing the residence pictured in Figure 3-13 (red box). ............................ 3-20

Figure 3-17: Outdated 2005 FIRM versus current effective 2009 FIRM with updated coastal 

analysis that includes storm erosion in Rincón around the house shown in 

Figure 3-14 (red box). .................................................................................................... 3-21

Figure 3-18: Painted concrete, a typical flood-damage-resistant interior finish, in a concrete 

house under construction in Yabucoa. ......................................................................... 3-22

Figure 3-20: Water ponding on flat concrete roof of a residence in San Juan. .............................. 3-23

Figure 3-19: Wood roof in Toa Alta that failed due to insufficient design and detailing, 

allowing rain to enter the building. It was constructed with wood panels or 

other materials that were not considered flood-damage resistant. ............................ 3-23

Figure 3-21: Wood framed residence in Toa Baja neighborhood pushed off its foundation 

by high velocity riverine flooding. ................................................................................ 3-24

Figure 3-22: Concrete house in Utuado impacted by sheet flow flooding. ..................................... 3-24

Figure 3-23: Failed CMU wall (red circle) attached to columns at a house in Isabela. The 

failure contributed to the collapse of a residential deck supported by the 

columns. Current FIRM: Unshaded Zone X. Advisory Data: Unshaded Zone X, 

Erosion-impacted area................................................................................................... 3-25

Figure 3-24: Solar water heater and cistern on a residential concrete roof in Rincón. ................. 3-26

Figure 3-25: Typical overhangs (aleros) above the windows of a concrete residence. .................... 3-26

Figure 3-26: Air conditioning equipment elevated on a cantilever at a concrete house 

in Punta Santiago, Humacao. This means of elevating equipment typically 

performed well, as here. ................................................................................................ 3-27 
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Figure 3-27: This frame supporting a residential cistern did not appear to be professionally 

designed. ........................................................................................................................ 3-27

Figure 3-28: Example of a continuous load path in a concrete building with masonry infill. ...... 3-29

Figure 3-29: Example of a wood-framed home in Vieques that performed well during 

Hurricane Maria. ...........................................................................................................3-30

Figure 3-30: Wood-framed house in Toa Baja. With the loss of the roof and wood-framed 

structural walls, the elevated living space was completely destroyed. ........................ 3-31

Figure 3-31: Concrete house with major damage to wood-framed roof system. ............................ 3-31

Figure 3-32: Informally constructed second story wood-framed addition in Loíza with 

partial loss of metal panel roof covering and wood-framed roof system. .................. 3-32

Figure 3-33: Second story wood-framed addition in Canovanas which lost the entire woodframed roof on the second story addition. .................................................................. 3-32

Figure 3-34: Comparison of two homes in Caguas: Left, the beige house had a reinforced 

concrete roof deck and experienced no structural damage; right, the blue 

CMU home lost most of its wood-framed roof and metal panel roof covering. ........ 3-33

Figure 3-35: Concrete residences in, left, Palmas del Mar; right, Loíza, that performed well 

with no structural damage. ........................................................................................... 3-33

Figure 3-36: Failure of reinforced concrete roof deck over garage. Source: Héctor J. 

Cruzado, PhD, PE and Gustavo E. Pacheco-Crosetti, PhD, PE. ................................. 3-34

Figure 3-37: This home in Vieques had rebar exposed on the roof (red circles), indicating 

that the homeowner planned to add a second story sometime in the future. .......... 3-34

Figure 3-38: Low-rise building on the coast in Palmas del Mar that lost tile roof coverings. ....... 3-35

Figure 3-39: Elevated concrete residential building with glass jalousie windows. .......................... 3-36

Figure 3-40: Close-up of jalousie windows with metal louvers on a residential building. .............. 3-37

Figure 3-41: Low-rise residential building with large glazed windows blown in (yellow 

arrows) and windows broken (red arrow). ................................................................... 3-38

Figure 3-42: Concrete single-family home with casement windows. Windows seal around 

opening (red arrows) and lock from inside to prevent water intrusion. .................... 3-39

Figure 3-43: Concrete single-family home with impact-resistant glazing covering windows 

and doors (red arrows). ................................................................................................. 3-39
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Figure 3-44: Newer low-rise restaurant in Bayamón with impact-resistant glazing panel (red 

inset) that performed well after being impacted, likely reducing further damage. .3-41

Figure 3-45: Metal hurricane shutter over glazed opening, (yellow arrow). Window unit air 

conditioner below window was not protected (red arrow) and became a source 

of water intrusion. ..........................................................................................................3-41

Figure 3-46: Residential building with accordion-style shutters (yellow arrows) on second 

story over glass jalousie windows and metal panel shutters (blue arrow) on first 

floor. Glass was protected by shutters, and no windows were broken. Exterior 

finish was damaged (red arrows). .................................................................................3-42

Figure 3-47: Residential building with metal panel shutters over windows and exterior 

doors (blue arrows). Damage is visible on exterior finish (red arrows). ....................3-42

Figure 3-48: Residential windows, protected on the left (yellow arrow) and unprotected on 

the right, (red arrow) in Loíza. The unprotected windows were damaged and 

subsequently boarded up. .............................................................................................3-43

Figure 3-49: Residential building missing entire roof covering.......................................................3-44

Figure 3-50: Metal roof covering with no structural decking. .........................................................3-44

Figure 3-51: House with metal roof and nailers pulled from its roof structure with no 

structural decking. .........................................................................................................3-45

Figure 3-52: House with a corroded metal roof (red circles)...........................................................3-46

Figure 3-53: Residence with metal roof covering damage. ..............................................................3-46

Figure 3-54: Clay roofing tiles inadequately attached to a roof with glue in Palmas del Mar, 

Humacao. ....................................................................................................................... 3-47

Figure 3-55: Tiles installed on felt over a wooden roof deck. Tiles were removed, but the 

deck remained in place. ................................................................................................ 3-47

Figure 3-56: Tile roof performance with secondary protection from decking system. Tiles 

were removed, but the decking remained in place. ....................................................3-48

Figure 3-57: Roof damage from wind speed-up effects in Palmas del Mar in Humacao 

along the eastern coastline. ..........................................................................................3-49

Figure 3-58: Top, overhead view of neighborhood atop a mountainside in Cayey after 

Hurricanes Irma and Maria, showing locations of damaged buildings; below, 

street-level views of homes (red and blue boxes) and collapsed MBS (yellow 

box) shown in overhead. (Source: Aerial image taken October 4, 2017 [NOAA 

2017]). .............................................................................................................................3-50
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Figure 3-59: Complete failure of informal construction of upper floor structure in Camino 

Nuevo, Yabucoa. ............................................................................................................. 3-51

Figure 3-60: Good performance of cast-in-place concrete house set along the steep hillside 

of Jajome Alto, Cayey. .................................................................................................... 3-51

Figure 3-61: Hillside house in Jajome Alto, Cayey. The main building demonstrates good 

performance under wind speed-up effects, while the informally constructed 

canopy suffered partial failure (canopy debris, red circles). ...................................... 3-52

Figure 3-62: Sample building placement along hillside development, showing angles of the 

natural slope and the developed slope. Slope angles are exaggerated. ..................... 3-53

Figure 3-63: USGS geologic map of Utuado with location of hillside residence in Figure 3 

65 (blue square). Modified from Nelson (1967). .........................................................3-54

Figure 3-64: USGS geologic map of Ciales, with location of hillside residence shown in 

Figure 3 66 (blue square). Modified from Berryhill (1965). ....................................... 3-55

Figure 3-65: Hillside residence in Cerro Gordo, Utuado that failed due to poor siting on 

unstable slope and poor connection of wood foundation to building. .....................3-56

Figure 3-66: House that failed due to landslide in Utuado. Source: NWS (2017)..........................3-56

Figure 3-67: Hillside house in Ciales at risk of landslide failure. The house was occupied 

despite the apparent risk. .............................................................................................. 3-57

Figure 3-68: Hillside mixed-use building in Ciales with extensive lower-level additions at 

risk of landslide failure. ................................................................................................. 3-57

Figure 3-69: Hillside residence in Utuado that was sited away from the edge of the slope 

and designed to resist potential flood and wind forces. .............................................3-58

Figure 3-70: A homeowner in Culebra attempted to increase the resistance of the roof to 

wind uplift forces by means of a steel cable (red arrow) wrapped over roof 

members and anchored to a column. Such an addition should consider the 

design loads. ................................................................................................................... 3-59

Figure 3-71: This home on Culebra had a plywood roof with a liquid-applied membrane 

consistent with the Home Protection Roofing Program in the USVI. The roof 

performed well. .............................................................................................................. 3-59

Figure 3-72: Elevated concrete house in Monseratte, Toa Baja subjected to flooding and 

high winds. .....................................................................................................................3-60
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Figure 3-73: Aerial image of Campanilla NSHP community, Toa Baja. The community was 

elevated on fill, resulting in isolation of properties during Hurricane Maria 

due to flooding of surrounding areas. Homes on the southern portion of the 

community experienced shallow flooding. Zone AE. Inset, NSHP home in 

Campanilla showing approximate inundation depth (yellow line). ...........................3-62

Figure 3-74: This NSHP house in Campanilla Toa Baja suffered damage to aesthetic 

components including clay tile roof coverings and decorative eaves blown off 

by wind. ..........................................................................................................................3-63

Figure 3-75: NSHP house in Campanilla has an informally constructed addition which lost 

its entire roof covering. .................................................................................................3-63

Figure 3-76: A Portion of the 2009 effective FIRM for Campanilla, Toa Baja, with locations 

of NSHP homes shown in Figure 3-73 (orange box), Figure 3-74 (red box), and 

Figure 3-75 (yellow box). ...............................................................................................3-64

Figure 4-1: Schools visited by the MAT and discussed in this report. Schools with an 

asterisk were designated for use as shelters.................................................................... 4-2

Figure 4-2: Mud remains in a classroom that was flooded (yellow line) at the Luis M. 

Santiago School, located in Zone AE. ............................................................................4-4

Figure 4-3: A portion of the effective 2009 FIRM showing the old Toa Baja Municipal 

Building (upper yellow box) and Luis M. Santiago School (lower yellow box). ..........4-5

Figure 4-4: A portion of the effective 2009 FIRM showing the new Toa Baja Municipal 

Building. The facility was relocated in 1995 to reduce flood risk; however, it is 

partly located inside the SFHA. ......................................................................................4-5

Figure 4-5: Floodwaters from the stream under this bridge rose to the edge of the 

mapped Zone AE (yellow line) in the parking lot immediately adjacent to the 

school. The floodwaters did not enter the school. ........................................................4-6

Figure 4-6: Luis M. Santiago School with location of high water mark (yellow line) from Maria. 4-7

Figure 4-7: Classroom at Luis M. Santiago School with high-water line indicated (yellow line)... 4-7

Figure 4-8: Adolfina Irizarry de Puig School building partially elevated with bracing 

added as seismic retrofitting. Wind damaged these HVAC units. The school 

received 2.5 - 3 feet of flooding (yellow line). ................................................................4-8

Figure 4-9: Toa Baja High School building student center area underneath the elevated 

building that flooded during Maria. The school received 2.5- 3 feet of flooding 

(yellow line). .....................................................................................................................4-8
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Figure 4-10: High water mark on wall (red arrow) and electrical panel at the Luis M. 

Santiago School. Flooding of the electrical panel impacted the electrical 

system across the first floor. ............................................................................................ 4-9

Figure 4-11: Loíza Vocational High School was constructed in 2010 and did not experience 

structural damage to the MWFRS from Hurricane Maria. ........................................ 4-10

Figure 4-12: Eduardo Garcia Carrillo High School, left, did not experience structural 

failures to reinforced concrete classroom buildings. Damage at these buildings 

was due to water intrusion from the roof, right, and through windows. ................... 4-11

Figure 4-13: Gutierrez Elementary School experienced loss of metal roof deck panels and 

some purlins from wind uplift. ..................................................................................... 4-12

Figure 4-14: Two MBSs used as athletic facilities at Loíza Vocational High School that 

performed well and were not observed to have wind damage from Hurricane 

Maria. ............................................................................................................................. 4-12

Figure 4-15: The Felix Pedraza Athletic Complex in Ceiba experienced cladding failures 

and partial failure of its MWFRS. ................................................................................ 4-13

Figure 4-16: Left, the end bay of this MBS athletic facility failed when it could not resist 

wind pressures during Hurricane Maria. Corroded structural members, right, 

likely contributed to the failure. In this column, a hole had formed in the web 

(red arrow) ..................................................................................................................... 4-13

Figure 4-17: Metal panel jalousies at this school were backed with screens across the 

second-floor classrooms and with plexiglass panels on the first-floor laboratory 

areas.................................................................................................................................4-14

Figure 4-18: Metal panel jalousie windows at Georgina Baquero High School, constructed 

in 1989. These windows are used across the entire exterior for classrooms and 

offices. This wing of the school was used as a shelter during Hurricanes Irma 

and Maria. ...................................................................................................................... 4-15

Figure 4-19: Broken skylight glazing at a high school in Canóvanas. ............................................. 4-15

Figure 4-20: Modified bitumen roof covering at a school in Canóvanas, left, and detail, 

right. This roof was approximately 2 years old and performed well during both 

Irma and Maria. The roof covering is terminated and flashed on the backside 

of the parapet................................................................................................................. 4-16

Figure 4-21: Modified bitumen roof covering at a high school in Loíza. ........................................4-17

Figure 4-22: Jose Robles Otero Elementary School. Left, façade; right, roof with lost 

flashing (red circle). .......................................................................................................4-17

Figure 4-23: Collapsed awning from wind uplift at Jose Robles Otero Elementary School .......... 4-18
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Figure 4-24: Older MBS at Eduardo Garcia Carrillo High School in Canóvanas. These 

roofs performed well except for ridge cap loss and damage from falling trees. ....... 4-18

Figure 4-25: Roof covering with two rows of connections near edge of roof covering, left, 

performed better than roof covering with only one row of connections near 

edge, right. ..................................................................................................................... 4-19

Figure 4-26: Tile roof failure at The Palmas Academy in Palmas del Mar. .................................... 4-19

Figure 4-27: Two examples of rooftop equipment failure that allowed water to enter the 

building. Left, wind removed an HVAC unit access panel at The Palmas 

Academy. Right, a toppled vent stack (yellow arrow) allowed water intrusion 

into the building (red arrow) at Loíza Vocational High School. ............................... 4-20

Figure 4-28: Left, Jose Robles Otero Elementary School had concrete walls that may have 

shielded rooftop equipment from wind. Right, small rooftop equipment at 

Eduardo Garcia Carrillo High School in Canóvanas was not properly secured 

and was displaced by wind forces from Maria. ............................................................ 4-20

Figure 4-29: Vent stacks secured with guy wires at Loíza Vocational High School were 

toppled by high winds when the threaded adjustment connectors failed due to 

corrosion, leading to water intrusion in the building. ................................................ 4-21

Figure 4-30: Exterior view of classrooms used for shelters at the high school in Canóvanas. ....... 4-23

Figure 4-31: Left, multiple rooms within the gym building was used for sheltering during 

both Hurricane Irma and Maria. ................................................................................. 4-23

Figure 4-32: This detached residential safe room funded through HMGP in Culebra was 

modified into a studio/efficiency apartment and no longer complies with 

FEMA P-361 criteria. Modifications included additional openings which 

reduced the level of protection provided by the building. ......................................... 4-26

Figure 5-1: Fire stations, police stations, other public buildings, and hospitals visited by 

the MAT and discussed in this report. ........................................................................... 5-2

Figure 5-2: Pavia Arecibo Hospital. ...................................................................................................5-4

Figure 5-3: A portion of the effective 2009 FIRM showing Pavia Arecibo Hospital in Zone 

X, an area of minimal flood hazard. ..............................................................................5-5

Figure 5-4: A portion of the effective 2009 FIRM showing Dr. Ramon Ruiz Arnau 

University Hospital, Bayamón, in Zone X. .....................................................................5-6

Figure 5-5: Dr. Ramon Ruiz Arnau University Hospital lower loading dock, which flooded 

from surface runoff, showing approximate high water level (red line), backup 

generator (red arrow), fuel tank (blue arrow), trailer mounted generator 

(yellow arrow), and propane tank (green arrow). .........................................................5-6
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Figure 5-6: The loading dock area at Dr. Ramon Ruiz Arnau University Hospital flooded 

when the area drains (red arrow) were overwhelmed by surface runoff. .................... 5-7

Figure 5-7: Location of San Juan University Pediatric Hospital in Zone X, an area of 

minimal flood hazard, on the effective FIRM. .............................................................. 5-7

Figure 5-8: View of the front entrance of the San Juan University Pediatric Hospital. .................5-8

Figure 5-9: A portion of the effective 2009 FIRM showing Susana Centeno Family Health 

Center in an X Zone. .......................................................................................................5-8

Figure 5-10: Susana Centeno Family Health Centers in Vieques. ..................................................... 5-9

Figure 5-11: This view of Pavia Arecibo Hospital shows that some windows had glazing 

protection (red arrow) while others did not (green arrows). ..................................... 5-10

Figure 5-12: At Pavia Arecibo Hospital, a window frame was pulled out of the building 

(green circle). The frame was inadequately anchored to the wall opening. ............. 5-10

Figure 5-13: Rain water from the fourth floor of Dr. Ramon Ruiz Arnau University 

Hospital, Bayamón, migrated to the lower floor through floor penetrations 

and inundated numerous systems including electrical conduits and 

communications boxes (green arrow). ......................................................................... 5-10

Figure 5-14: Water infiltrated the floors below and was captured to minimize further 

damage at Dr. Ramon Ruiz Arnau University Hospital. ..............................................5-11

Figure 5-15: View of central section of Dr. Ramon Ruiz Arnau University Hospital showing 

broken windows as well as entire window and frame missing from wall (red circle). 5-11

Figure 5-16: A 25-foot (7.6-meter) section of window and frame are missing from the 

fourth-floor wall of Dr. Ramon Ruiz Arnau University Hospital (red arrow). ........... 5-12

Figure 5-17: Only two fasteners were observable restraining the lower section of the 

missing 25-foot (7.6-meter) section of window system at Dr. Ramon Ruiz Arnau 

University Hospital (red arrows). .................................................................................. 5-12

Figure 5-18: Successes and problems related to installation of shutter systems over glazed 

doors and windows, including a shutter system properly installed (green 

arrow), a shutter system with a track missing at a glazed door (red arrow), a 

window air conditioning unit preventing a shutter being deployed (orange 

arrow), and a pair of glazed doors without glazing protection (yellow arrow). ........ 5-13

Figure 5-19: The roof membrane over the central section of Dr. Ramon Ruiz Arnau 

University Hospital peeled off over most of the roof, allowing water intrusion 

into the floors below. ......................................................................................................5-14
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Figure 5-20: The roof membrane at Dr. Ramon Ruiz Arnau University Hospital tore free 

from its mechanical fasteners. ...................................................................................... 5-15

Figure 5-21: Roof covering puncture at Susana Centeno Family Health Center. .......................... 5-15

Figure 5-22: View across the roof of Susana Centeno Family Health Center, looking south. ...... 5-16

Figure 5-23: Interior of the Culebra Community Health Center, which experienced water 

intrusion through the roof. ........................................................................................... 5-16

Figure 5-24: Damage to rooftop HVAC equipment at Pavia Hospital Arecibo. ..............................5-17

Figure 5-25: Damaged rooftop HVAC unit at Pavia Arecibo Hospital showing extensive 

corrosion. The unit is upside down and is missing side panels. The anchorage 

points on the bottom (now facing up) are rusted through and torn out. ................. 5-18

Figure 5-26: Loss of signage at Pavia Hospital Arecibo. The sign frame or armature was 

inadequately attached to the parapet, and the fasteners failed. ................................ 5-18

Figure 5-27: Rooftop fan at Dr. Ramon Ruiz Arnau University Hospital displaced from 

support frame by hurricane winds. Vibration isolation mounts can be seen in 

the corners (red arrows) and part of another next to the frame (green arrow). ...... 5-19

Figure 5-28: Rooftop equipment located on top of one of University Hospital towers that 

was blown over. .............................................................................................................. 5-19

Figure 5-29: A rooftop fan damaged by winds at Dr. Ramon Ruiz Arnau University Hospital. .... 5-20

Figure 5-30: Small air handling units displaced and off their stands on top of the roof. 

Note displaced electrical conduit in background of photo (red arrow). ................... 5-20

Figure 5-31: Rooftop solar array at east corner of hospital roof. The blue arrow indicates 

the direction of the strongest winds based on debris fields observed around 

the hospital. .................................................................................................................... 5-21

Figure 5-32: Rooftop solar array at east corner of hospital roof showing damage from windborne debris impacts (red circles). ............................................................................... 5-21

Figure 5-33: Hospital Generator (blue arrow) and two FEMA-Supplied Generators (yellow 

arrows) at Pavia Hospital Arecibo. ................................................................................ 5-22

Figure 5-34: View of one of the standby generators (red arrow), two of the backup 

generators (green arrows), and a fuel tank (blue arrow) at San Juan University 

Pediatric Hospital. ......................................................................................................... 5-23

Figure 5-35: View of fuel truck refilling the fuel tank for University Hospital Tower One. 

Note the tight clearance between the porte-cochere ceiling and the top of the 

tanker truck (red arrow.) .............................................................................................. 5-24
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Figure 5-36: Culebra Community Health Center functioned on generator power after 

Hurricanes Irma and Maria. Source: Hector Huyke Villeneuve / FEMA, 

December 9, 2017 .......................................................................................................... 5-25

Figure 5-37: This HVAC unit at the Culebra Community Health Center is strapped 

to a concrete platform; however, it rests on plastic supports that are not 

mechanically anchored. ................................................................................................ 5-26

Figure 5-38: Elevator mechanical penthouse enclosing the elevator gear at Dr. Ramon Ruiz 

Arnau University Hospital. Note ventilation louvers on the sides where rain 

entered. .......................................................................................................................... 5-27

Figure 5-39: Elevator controls that were inundated with wind-driven rain and failed during 

the hurricane at Dr. Ramon Ruiz Arnau University Hospital. ................................... 5-27

Figure 5-40: Elevator gear and controls located in the elevator penthouse at Dr. Ramon 

Ruiz Arnau University Hospital. ................................................................................... 5-27

Figure 5-41: Location of the Culebra Police Station on the effective 2009 FIRM. The 

facility was not damaged by coastal inundation. ......................................................... 5-29

Figure 5-42: Location of the Luquillo Fire Station on the effective 2009 FIRM. The facility 

was not damaged by coastal inundation. ..................................................................... 5-29

Figure 5-43: Corozal Police Station, top, shown on the effective 2009 FIRM; bottom, shown 

on the Advisory Data. .................................................................................................... 5-30

Figure 5-44: Corozal Police Station, left, overview; center, damaged backup generator; 

right, portable generator used after Hurricane Maria. Yellow line indicates 

high water mark. ............................................................................................................ 5-31

Figure 5-45: A portion of the effective 2009 FIRM showing the Toa Baja Police Station. ............. 5-32

Figure 5-46: Toa Baja Police Station (left), damaged files and office equipment (center), 

electrical damage (red circle-right). Yellow line indicates high water mark. ............. 5-32

Figure 5-47: Left, approximate flood elevation and power generator (red circle) in the 

background; right, steps to the first floor (right) of the Toa Baja Fire Station. ........ 5-33

Figure 5-48: Toa Baja Fire Station. Left, security grills (red arrows) protected equipment 

from wind-borne debris. Right, metal shutters (blue arrows) protected the 

building from wind-borne debris. ................................................................................ 5-33

Figure 5-49: Metal shutters installed at the Luquillo Fire Station successfully protected the 

facility’s openings. ......................................................................................................... 5-34

Figure 5-50: Metal shutters installed at the Florida Fire Station successfully protected the 

facility’s openings. ......................................................................................................... 5-34
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Figure 5-51: The Palmas del Mar community requires decorative tile roofs. The Palmas 

del Mar Fire Station included decorative tile roof coverings over portion of 

the building (red circles). The tiles were not mechanically attached, and some 

failed, contributing to wind-borne debris. ................................................................... 5-35

Figure 5-52: Damage to tile roof (red oval) covering at the Palmas del Mar Fire Station. 

Red arrows indicate broken tiles. ................................................................................. 5-35

Figure 5-53: Ponding and roof damage (red arrows) at the Culebra Police Station. ..................... 5-36

Figure 5-54: Rooftop equipment at the Luquillo Fire Station, including, left, air 

conditioning unit; center, cooling fan; right, rooftop damage. ................................. 5-36

Figure 5-55: Florida Fire Station, with, left, minor roof damage, right, strapped AC 

condensers. ..................................................................................................................... 5-37

Figure 5-56: San Juan EOC, left, exterior, right, interior. ................................................................ 5-37

Figure 5-57: Toa Baja Fire Station. Left, generator (red circle) with temporary piping 

system (red arrow) installed to convey generator smoke away from the 

building. Right, portable generator supplied after Hurricane Maria. ....................... 5-38

Figure 5-58: View of the northeast corner of the PRDOJ building in San Juan after 

hurricane Maria. ........................................................................................................... 5-39

Figure 5-59: A portion of the effective 2009 FIRM showing the PRDOJ building in the X Zone. 5-40

Figure 5-60: Toa Baja Municipal Building showing relief from surrounding terrain by use 

of elevation on fill. Stairs lead to the building’s elevated pad (red arrow). ............... 5-41

Figure 5-61: Toa Baja Municipal Building showing relief from surrounding terrain and 

entrance to underground parking (red arrow). .......................................................... 5-41

Figure 5-62: A portion of the effective 2009 FIRM showing the Culebra Municipal 

Building. The facility is partially in the SFHA but was not damaged by coastal 

inundation. ..................................................................................................................... 5-41

Figure 5-63: Northwest view of Vega Alta Municipal Building. The building is located 

outside the SFHA and did not flood. ...........................................................................5-42

Figure 5-64: A portion of the effective 2009 FIRM showing the Vega Alta Municipal 

Building in Zone X. The facility was not damaged by flooding. ................................5-42

Figure 5-65: View of the northwest side of the PRDOJ building with numerous windows 

broken. ............................................................................................................................5-43

Figure 5-66: Window frames pushed into the PRDOJ building at the top floor due to the 

failure of frame-to-structure anchors, (red arrows). ...................................................5-43
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Figure 5-67: View of the undersized anchorage location, (red arrows) in the window frame 

at the PRDOJ building. .................................................................................................5-44

Figure 5-68: The screws that held the window frame in place bent and pulled through the 

window frame at the PRDOJ building. The anchors (red circles), were too 

small and too few in number. .......................................................................................5-44

Figure 5-69: A shattered window (red arrow) allowed water and wind into the PRDOJ 

building at this location, inundating the documents on the adjacent shelf. .............5-44

Figure 5-70: Left, shutters protecting lower floor windows pulled off the PRDOJ building, 

exposing the glass behind; right, the anchors were undersized, of the wrong 

type, and too few in number. ........................................................................................5-44

Figure 5-71: Vega Alta Municipal Building had shutters on only the east side windows (red 

arrows). No shutters or opening protection is present on windows on this side 

of the building. ..............................................................................................................5-45

Figure 5-72: Glazing damage (red arrow) at Toa Baja Municipal Building. ...................................5-45

Figure 5-73: Metal shutters protected some upper-story glazed windows at Bayamón 

Municipal Building. .......................................................................................................5-46

Figure 5-74: Broken window glazing (red arrows) at Bayamón Municipal Building. ....................5-46

Figure 5-75: Vega Alta Municipal Building had roof leaks. Flashing can be seen displaced 

at the mechanical area of the roof. Water entered this location as well as others. ... 5-47

Figure 5-76: Membrane roof covering at Culebra City Hall punctured (red arrow) during 

hurricane winds led to water intrusion in building that damaged acoustical 

ceilings (yellow arrow) and drywall. .............................................................................5-48

Figure 5-77: Metal roof covering at Culebra Municipal Building performed well. There is 

no evidence of corrosion from this view. .....................................................................5-48

Figure 5-78: The lighting protection air terminals (green arrow) tore free from their 

anchorages (red arrow) atop the PRDOJ building. Rooftop AC units were also 

displaced (blue arrow). ..................................................................................................5-49

Figure 5-79: HVAC equipment was blown off equipment pads at the roof level of the 

PRDOJ building. One HVAC condenser has been blown to the edge of the 

building (yellow circle). .................................................................................................5-49

Figure 5-80: A rooftop fan unit is missing from this location atop the PRDOJ building 

(yellow circle). ................................................................................................................5-50
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Figure 5-81: View of a service access door to the rooftop cooling towers atop the PRDOJ 

building. The door was driven into the cooling tower by debris impact (red 

arrow). ............................................................................................................................5-50

Figure 5-82: View of rooftop mechanical equipment displaced and damaged by the 

hurricane winds. Left, the access panels were blown off (yellow circle). Right, 

the units were moved off their mounting pedestals (red arrow). .............................. 5-51

Figure 5-83: View of rooftop mechanical equipment displaced (yellow circle) and damaged 

by the hurricane winds. ................................................................................................. 5-51

Figure 5-84: Mechanically attached rooftop equipment performed well at Culebra 

Municipal Building. Some fasteners were corroded (red arrow) but did not fail. .... 5-52

Figure 5-85: Rooftop equipment at Bayamón Municipal Building including, left, HVAC 

unit attached with screws to a curb; right, an AC condenser resting on 

plastic supports without anchoring. Rooftop equipment was not significantly 

displaced during Hurricanes Irma and Maria. ........................................................... 5-52

Figure 6-1: Location map showing ground-mounted PV facilities visited by the MAT. ................. 6-2

Figure 6-2: High wind damage to ground-mounted photovoltaic (PV) systems in the 

Reden Solar Array, Humacao, showing panels in Phase 1, left; hill separating 

the two phases, center; and Phase 2, right. .................................................................... 6-3

Figure 6-3: Reden solar array in Humacao, with ground-mounted posts (green arrow), 

sloped beams (blue arrows), and lateral rails (red arrow), that directly support 

the PV panels. In this image some of the panels have been lifted off the 

ground-mount structure, with the failure occurring at the panel clips. ..................... 6-3

Figure 6-4: Reden solar array in Humacao: Left, side view of a hat-shaped clip showing 

its bolted connection to the lateral rail member underneath. Right, top view 

showing that a single bolt secures it to the rail. .............................................................6-4

Figure 6-5: Reden solar array in Humacao: A deformed hat-shaped clip still bolted to its 

supporting lateral rail. The PV panel to the left was lifted out of position when 

the hat-shaped clip could not resist the wind uplift pressures and was bent upward. 6-4

Figure 6-6: Reden solar array in Humacao: In this image, only the bent angle (red circle), 

remains after the steel lateral rail and bolted attachment were pried away in 

the hurricane. ..................................................................................................................6-5

Figure 6-7: Reden solar array in Humacao: Three deformed steel lateral rails (red arrows). 

In a number of cases the C-shaped lateral rail connections were unable to 

maintain connection to the steel beams in the high winds. .........................................6-5
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Figure 6-8: Reden solar array in Humacao: Aerial view of the Phase 2 Array with most 

PV panels removed from their ground-mount supports and many structural 

members damaged. .........................................................................................................6-6

Figure 6-9: Oriana Solar Array 1: Aerial view of one of the more damaged areas within the 

Oriana Solar Array. ......................................................................................................... 6-7

Figure 6-10: Oriana Solar Array 1, showing ground-mounted posts (green arrows), sloped 

beams (blue arrows), and lateral rails (red arrows), directly supporting the PV 

panels. This array also has a brace connecting each row of posts (pink arrows). ....... 6-7

Figure 6-11: Oriana Solar Array 1: The brace connecting each row of posts (pink arrows) 

provides additional strength to the posts and helps limit the overall sway or 

movement of the PV array perpendicular to the lateral rails (red arrow). The 

yellow arrow in the image points to a brace which connects posts parallel to 

the lateral rails. This brace will assist the system in a similar manner in the 

opposite direction. ...........................................................................................................6-8

Figure 6-12: Oriana Solar Array 1: The horizontal brace (blue arrow) connecting rows of 

lateral rails (red arrow) helps distribute wind loads through the structural 

system and utilize less dependence upon the PV panels to brace the structural 

system. The horizontal brace also helps resist torsional or twisting action on 

the ground-mount system. ..............................................................................................6-8

Figure 6-13: Oriana Solar Array 1: Steel lateral rail missing bolt and Hat-clip which held 

the adjacent PV panel. .....................................................................................................6-9

Figure 6-14: Oriana Solar Array 1: Steel lateral rail (yellow arrow) still bolted to the clip 

which secures the PV panel to the ground-mount system. Notice the single 

steel nut (red arrow) which could back off the bolt. .....................................................6-9

Figure 6-15: Puerto Rico Convention Center Solar Array: Some PV panels were lost (red 

circles) from these carports. Based upon aerial imagery, it is estimated that 

fewer than 5 percent of the panels at this site were damaged or removed (Civil 

Air Patrol 2017). ............................................................................................................. 6-10

Figure 6-16: Puerto Rico Convention Center Solar Array, showing structural members 

supporting the solar array looking from the underside of the canopy. The 

arrows designate the following structural members: steel column (green 

arrow), tapered steel girder (yellow arrows), steel kickers (pink arrows) 

supporting girder, steel beams (blue arrows) running perpendicular to the 

girder, steel lateral rails (red arrows) directly supporting the PV panels. ................. 6-11

Figure 6-17: Typical anchoring system used for rooftop equipment in concrete slab roof, 

with, top, concrete anchoring system using an expansion plug placed in the 

roof slab after drilling a hole, bottom, a concrete expansion anchorage bolt. ......... 6-12

Figure 6-18: Solar water heater unit with flat solar collector panel in Canóvanas. ........................ 6-13
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT xxvii

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Figure 6-19: Solar water heater system missing solar collector panel on the flat slab 

concrete roof of a two-story concrete house in El Negro, Yabucoa. ........................... 6-13

Figure 6-20: Reference wind speed near Caguas at CariCOOS/Weather Flow 

meteorological station, Gurabo. ....................................................................................6-14

Figure 6-22: PV power system installed on a flat concrete slab roof in Naguabo with no 

visible damage. ............................................................................................................... 6-15

Figure 6-21: Solar water heater system with no evident wind damage on a concrete slab roof 

of a one-story concrete house in Caguas...................................................................... 6-15

Figure 6-23: PV power system installed on a flat concrete slab roof in Caguas with no visible 

damage. .......................................................................................................................... 6-16

Figure 6-24: Clamp on a PV power system installed on a flat concrete slab roof in Caguas. ........ 6-16

Figure 6-25: Left, PV power system anchored to a flat concrete roof slab in Caguas; right, ...

closeup of bolted connection. ....................................................................................... 6-17

Figure 6-26: PV power system installed at Susana Centeno Family Health Center in Vieques. 

The system had significant wind damage due to wind-borne debris impact and 

clamp failures. ................................................................................................................ 6-18

Figure 6-27: PV power system installed at Susana Centeno Family Health Center in Vieques. 

Close-up view showing PV panels damaged by impact debris. ................................... 6-18

Figure 6-28: Clamps used at Susana Centeno Family Health Center. ............................................. 6-19

Figure 6-29: Clamp used to hold adjacent PV panels to frame. ....................................................... 6-19

Figure 6-30: Clamp used to attach adjacent PV panels to frame. .................................................... 6-20

Figure 6-31: Side view of clamp used to attach adjacent PV panels to frame. ................................ 6-20

Figure 6-32: Close-up view of the anchoring connection to the roof concrete slab. ...................... 6-21

Figure 6-33: Close-up view of the clamping mechanizing connection used to hold PV 

panels at the edges. ........................................................................................................ 6-21

Figure 6-34: Failure of conduit connected to the roof used for the PV power system. .................. 6-22

Figure 6-35: PV power system installed on the roof of Susana Centeno Family Health 

Center, Vieques (Source: aerial image taken September 24, 2017 [NOAA 2017]). ... 6-22

Figure 6-36: Reference wind speed at CariCOOS/WeatherFlow meteorological station, 

Culebrita......................................................................................................................... 6-23
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Figure 6-37: Views of the rooftop PV array at Culebra Ecological School, clockwise from 

top left: undamaged portion of the roof, roof covering failure, close-up of 

structural aluminum angle anchoring system attaching the PV panels to the 

concrete roof, open water exposure for the upwind fetch of the intense winds, 

close-up of failed roof covering section showing exposed rigid insulation foam, 

view of corrosion on metal roof edge flashing on portion of roof with roof 

covering failure. ............................................................................................................. 6-24

Figure 6-38: Reference wind speed at CariCOOS/WeatherFlow meteorological station buoy 

south of Ponce. The station failed to record some values during Hurricane 

Maria; therefore, actual wind speeds and pressures at this station may be more 

extreme than those discussed. ...................................................................................... 6-25

Figure 6-39: PV power system at Zimmer Biomet in Mercedita, Ponce, which lost four of its 

eight panels. ................................................................................................................... 6-26

Figure 6-40: Close-up views of the aluminum framing system of the PV power system at 

Zimmer Biomet facility in Mercedita, Ponce. .............................................................. 6-26

Figure 6-41: Failure of steel communication tower in Cayey. .......................................................... 6-27

Figure 6-42: Wind turbines damaged by the hurricanes in Naguabo, along the 

northeastern coastline of Puerto Rico. ........................................................................ 6-27

Figure 6-43: Failure of radar bubble on communication tower in Cayey. The tower itself 

appeared undamaged. .................................................................................................. 6-27

List of Tables

Table 1-1: The Saffir-Simpson Hurricane Wind Scale ......................................................................... 1-3

Table 1-2: Costliest U.S. Hurricanes in 2017 Dollars ............................................................................1-7

Table 2-1: Municipalities with Delegated Permitting Authority and Permit Offices ......................... 2-6

Table 2-2: Design Wind Speeds for Puerto Rico, in mph (kph) ........................................................2-10

Table 2-3: Probability of Design Wind Speed Exceedance at Least Once in 50 years ......................2-11

Table 3-1: Summary of Major Types of Residential and Low-Rise Construction in Puerto Rico .....3-4

Table 3-2: Examples of Coastal Erosion Damage Observations ....................................................... 3-18

Table 7-1: Table of Conclusions and Recommendations ................................................................... 7-27
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 1-1

1

HURRICANES

IRMA AND MARIA

IN PUERTO RICO

MITIGATION ASSESSMENT TEAM REPORT

Introduction 

In September of 2017, Puerto Rico was impacted by two major 

hurricanes, Irma and Maria.

Hurricane Irma passed directly to the northeast of Puerto Rico on September 6, 2017, resulting in 

hurricane-force winds and island-wide power outages. On September 20, 2017, Hurricane Maria 

made landfall on the southeast coast of Puerto Rico as a Category 4 storm, resulting in widespread 

damage throughout the islands. In response to the two hurricanes, the Federal Emergency 

Management Agency (FEMA) authorized a Mitigation Assessment Team (MAT) to deploy to Puerto 

Rico. A preliminary field team deployed in October and a full MAT in December 2017. 

The MAT Report’s primary purpose is to provide recommendations to improve building resistance 

to natural hazards, especially hurricane winds and flooding. It describes observations made 

during the MAT deployment, draws conclusions about drivers of building damage, and presents 

actionable solutions to the underlying causes of damage. This report also discusses several topics 

not emphasized in previous MAT reports:

● Successes of prior mitigation actions

● Formal and informal construction

● The effect of topographic features on building performance

● The performance of rooftop and ground-mounted solar photovoltaic (PV) systems 
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1.1 Organization of the Report

This report discusses Hurricanes Irma and Maria, regulatory issues, and the performance of various 

building types, and presents conclusions and recommendations, as follows: 

Chapter 1: Summarizes the meteorological history of Hurricanes Irma and Maria, the deployment 

of the MAT, the history of previous MAT efforts in Puerto Rico, and the MAT’s damage observations. 

Chapter 2: Discusses historical and current codes and standards; the adoption of, implementation of, 

and exceptions made to the building codes within various government municipalities; prescriptive 

allowances in the building code; standards for PV systems; and the National Flood Insurance 

Program (NFIP) in Puerto Rico. 

Chapter 3: Reviews the performance of residential and low-rise buildings. 

Chapter 4: Reviews the performance of schools and sheltering facilities. 

Chapter 5: Reviews the performance of hospitals, police and fire stations, and other mid-rise 

buildings.

Chapter 6: Reviews the performance of solar water heaters and rooftop and ground-mounted PV 

arrays. 

Chapter 7: Presents conclusions and recommendations for mitigation efforts. 

The appendices provide supplementary information: 

Appendix A: Acknowledgements

Appendix B: Bibliography

Appendix C: Abbreviations

Appendix D: Recovery Advisories for Hurricanes Irma and Maria in Puerto Rico

1.2 Overview of Recent Hurricanes

This section provides a meteorological and hazards overview of Hurricanes Irma and Maria in 

Puerto Rico. A discussion of observed flooding and wind speeds with respect to the building code 

may be found in Sections 1.5.4 and 2.4, respectively.

1.2.1 Hurricane Irma

Hurricane Irma was a long-lasting hurricane that reached Category 5 on the Saffir-Simpson 

hurricane wind scale (Table 1-1). In total, Irma made seven landfalls, including four as a Category 

5 hurricane, across the northern Caribbean islands. Hurricane Irma brought strong winds, heavy 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 1-3

INTRODUCTION

rains, and in some areas, high storm surge. The storm caused several deaths and widespread 

devastation across the Caribbean islands and southeastern continental United States. 

Irma formed near Cape Verde on August 30, 2017, and moved south and west, fluctuating between 

Categories 2 and 3 from September 1 to September 4, 2017 (Figure 1-1, top). The hurricane reached 

its maximum intensity of 178 miles per hour (mph) (287 kilometers per hour [kph]) sustained 

winds on September 5 about 80 miles (130 kilometers) eastsoutheast of Barbuda. On September 6, 2017, Irma made 

its first landfall on Barbuda as a Category 5 hurricane with 

maximum wind speeds of 178 mph (287 kph), making 

landfall next on St. Martin and Virgin Gorda. Irma’s eye 

passed 58 miles (93 kilometers) north of Puerto Rico’s 

capital, San Juan (and less than 30 miles [48 kilometers]) 

from Culebra) over September 6-7, 2017, before temporarily 

weakening to Category 4. Irma made landfall on Little 

Inagua in the Bahamas on September 8, 2017, and in Cuba 

on September 9, 2017, as a Category 5 hurricane with 167 

mph (269 kph) winds, after which its interaction with land 

caused it to quickly weaken to Category 2. Over the warm 

waters of the Straits of Florida, the storm re-intensified to a 

Category 4 before making its sixth landfall on Cudjoe Key 

with winds of 130 mph (215 kph) on September 10. Later 

that day, Irma made its seventh landfall on Marco Island 

in Florida as a Category 3 hurricane. Finally, the system 

degraded into a remnant low over Alabama and dissipated 

over Missouri on September 13, 2017, (Cangialosi, Latto 

and Berg 2018).

Hurricane Irma passed less than 30 miles (48 kilometers) from Culebra as a Category 5 hurricane 

with wind speeds estimated to be greater than 160 mph (257 kph). The highest wind speed recorded 

in the Commonwealth was 58 mph (93 kph) sustained, with a gust of 89 mph (143 kph), on the 

island of Culebrita. On the island of Puerto Rico, the highest recorded sustained wind speed was 55 

mph (89 kph), with a gust of 74 mph (118 kph), in San Juan Bay. Irma’s eye passed about 57 miles (92 

kilometers) north of San Juan on September 6 (Cangialosi, Latto and Berg 2018). 

The peak wind gust map (Figure 1-2) depicts the high winds experienced in eastern Puerto Rico 

during Irma, with the highest wind speeds on the islands of Culebra and Vieques and along the 

northeastern coast of the island of Puerto Rico. Figure 1-2 shows estimated 3-second wind gust 

speeds at 33 feet (10 meters) above ground level for open terrain (ASCE Exposure Category C) for 

comparison with ASCE 7 design wind speeds. In contrast, Figure 1-3 shows maximum measured 

sustained and gust wind speeds. Note that these observations may have been made at exposure 

conditions or elevations above ground that differ from those modeled in Figure 1-2.

Irma also caused storm surge flooding in a few areas on the north coast (Figure 1-4). The deepest 

inundation was 1–3 feet (0.3–0.9 meters) above ground level near Arecibo and west of San Juan in 

Bayamón and Dorado.

Table 1-1: The Saffir-Simpson Hurricane 

Wind Scale

Category

Wind Speed

mph kph

1 74–95 119–153

2 96–110 154–177

3 111–129 178–208

4 130–156 209–251

5 ≥ 157 ≥ 252

The Saffir-Simpson hurricane wind scale 

classifies hurricanes according to their peak 

1-minute wind speed at 33 feet (10 meters) 

above ground level over unobstructed terrain.
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INTRODUCTION

Irma produced heavy rainfall in the central and eastern portions of the island, with some higherelevation areas in the interior of the island of Puerto Rico experiencing 10–15 inches (25–38 

centimeters) of rain1 (Figure 1-5).

Figure 1-1: Top, Hurricane 

Irma’s track; bottom, Hurricane

Irma wind speed radii for 

39, 58, 74 mph (63, 93, 119 

kph) winds. Modified from 

Cangialosi, Latto, and Berg 

(2018).

1For Southern Canóvanas, where Irma’s rainfall was greatest, 10–15 inches (25–38 centimeters) corresponds to a 

recurrence interval of roughly 5–25-years, according to NOAA Atlas 14 frequency estimates (National Weather 

Service Hydrometeorological Design Studies Center 2008).
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INTRODUCTION

Figure 1-2: Preliminary peak wind gust map for Hurricane Irma with track (blue line). Estimated 

3-second gust wind speeds (mph) at 33 feet (10 meters) above ground for flat open terrain from 

ARA model fit to surface level observations. The model used smoothed National Hurricane 

Center storm track and central pressure data through Forecast/Advisory 52 at 03:00 UTC on 

September 12, 2017.

Figure 1-3: Peak sustained and gust wind speeds measured during Hurricane Irma. Data source: 

Cangialosi, Latto, and Berg (2018).
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Figure 1-4: Estimated storm surge inundation (feet above mean sea level) for Hurricane Irma. Data source: 

Coastal Emergency Risks Assessment (2017).

Figure 1-5: Estimated rainfall total from Hurricane Irma.
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INTRODUCTION

Table 1-2: Costliest U.S. Hurricanes in 2017 Dollars

Rank Hurricane Season Damage Rank Hurricane Season Damage

1 Katrina 2005 $160 billion 6 Andrew 1992 $48 billion

2 Harvey 2017 $125 billion 7 Ike 2008 $35 billion

3 Maria 2017 $90 billion 8 Ivan 2004 $27 billion

4 Sandy 2012 $70 billion 9 Wilma 2005 $24 billion

5 Irma 2017 $50 billion 10 Rita 2005 $24 billion

Source: National Hurricane Center (2018).

In addition to housing damage, more than a million residents lost power (U.S. Department of 

Energy 2017). Total economic losses from Hurricane Irma are estimated as $50 billion, making 

it the second-costliest Caribbean hurricane on record, behind only Hurricane Maria, and fifthcostliest in the U.S., in 2017 inflation-adjusted dollars (Table 1-2). However, much of Irma’s United 

States-based damage totals occurred in the U.S. Virgin Islands (USVI) and the continental U.S. 

including Florida and Georgia.

1.2.2 Hurricane Maria 

Three weeks after Hurricane Irma, Hurricane Maria was a Category 4 hurricane when it made 

landfall in Puerto Rico on September 20, 2017. The hurricane caused numerous deaths and 

extensive damage to the power grid. 

Maria originated east of the Lesser Antilles and became a tropical storm on September 16, 

proceeding west (Figure 1-6). As it approached the Caribbean islands, Maria intensified rapidly, 

with highly favorable environmental conditions; it became a Category 5 hurricane before making 

landfall on Dominica on September 18. Land interaction while crossing Dominica caused Maria 

to weaken, but it achieved its peak intensity over the eastern Caribbean with maximum sustained 

winds of 175 mph (280 kph). Maria weakened to Category 4, but increased in size, before making 

landfall in Puerto Rico on September 20 with maximum sustained winds of 155 mph (249 kph). 

The hurricane weakened gradually, becoming a tropical storm on September 28 as it moved north. 

Maria later accelerated eastward over the open Atlantic and dissipated by October 3.
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INTRODUCTION

Figure 1-6: Top, Hurricane 

Maria’s track, bottom, 

Hurricane Maria wind speed 

radii for 39, 58, 75 mph (63, 

93, 118 kph) winds. Modified 

from Pasch, Penny, and Berg 

(2018).

The peak wind gust map (Figure 1-7) depicts the estimated high winds experienced throughout 

the Commonwealth during Maria, with the highest winds on the island of Vieques and to the east 

of the center of the storm track through the island of Puerto Rico, including near San Juan. Figure 

1-7 shows estimated 3-second wind gust speeds at 33 feet (10 meters) above ground level for open 

terrain (ASCE Exposure Category C) for comparison with ASCE 7 design wind speeds. In contrast, 

Figure 1-8 shows maximum measured sustained and gust wind speeds. Note that these observations 

may have been made at exposure conditions or elevations above ground that differ from those 

modeled in Figure 1-7.
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INTRODUCTION

Figure 1-7: Preliminary peak wind gust map for Hurricane Maria with track (blue line). 

Estimated 3-second gust wind speeds (mph) at 33 feet (10 meters) above ground for flat open 

terrain from ARA model fit to surface level observations. The model used smoothed National 

Hurricane Center storm track and central pressure data through Intermediate Advisory 41A at 

12:00 UTC on September 26, 2017. 

Figure 1-8: Peak sustained and gust wind speeds measured during Hurricane Maria. Data 

source: Pasch, Penny, and Berg (2018).
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INTRODUCTION

Hurricane Maria caused maximum storm surge inundation of 6–10 feet (1.8–2.7 meters) above 

ground level to the east of Maria’s landfall along the coasts of Humacao, Naguabo, and Ceiba, as 

well as the north central municipality of Arecibo. To the southeast, in Yabucoa, Maunabo, Patillas, 

and Arroyo, maximum storm surge inundation was approximately 4–7 feet (1.2–2.1 meters). Along 

the remaining southern and northeastern coastline, maximum inundation of 3–5 feet (0.9–1.5 

meters) occurred from the municipality of Ponce eastwards. The remaining coastline generally 

experienced inundations ranging from 1 to 4 feet (0.3 to 1.2 meters). Additionally, the island of 

Vieques experienced 3–5 feet (0.9–1.5 meters) of maximum storm surge inundation. Figure 1-9 

depicts the storm surge along the Puerto Rico coastline caused by Hurricane Maria. 

Figure 1-9: Estimated storm surge inundation (feet above mean sea level) for Hurricane Maria. Data 

source: Coastal Emergency Risks Assessment (2017).

Heavy rainfall occurred throughout the Commonwealth during Maria, peaking at 37.9 inches (96.3 

centimeters) in Caguas (Figure 1-10). Severe flash flooding occurred in many locations. Thirty 

rivers reached major flood stage, and 13 of those were at or above record stages. Many bridges were 

destroyed. Communities along the Guajataca River were displaced when flooding compromised 

the stability of the dam at Guajataca Lake. Some of the most significant riverine flooding was 

associated with the La Plata River on the northern part of the island west of San Juan, including the 

municipality of Toa Baja, where hundreds were rescued from rooftops. Landslides associated with 

the high rainfall occurred throughout Puerto Rico, blocking thousands of roads (Martinez-Sánchez 

2018). 

High winds from Hurricanes Irma and Maria contributed to the extensive damage to buildings 

across Puerto Rico, with hundreds of thousands of homes damaged (Rosselló Nevares 2017). The 

combined effects of storm surge and wave action produced extensive damage to buildings and roads 

throughout the eastern and southeast coast. Significant damage also occurred along the north coast 

(Pasch, Penny and Berg 2018).
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INTRODUCTION

Figure 1-10: Estimated rainfall total from Hurricane Maria (National Weather Service 2017).

Maria caused lasting interruptions 

to essential services and 

severe damage to housing and 

infrastructure. A month after 

Maria, fewer than 8 percent of 

Puerto Rico’s roads were open and 

usable (Martinez-Sánchez 2018). 

Total losses from the hurricane 

are estimated at upwards of $90 

billion, mostly in Puerto Rico, 

making Maria the costliest U.S. 

Caribbean hurricane and thirdcostliest on record for the U.S. 

in 2017 inflation-adjusted dollars 

(Table 1-2).

HURRICANE MARIA’S DEATH TOLL

Hurricane Maria had a devastating impact on Puerto Rico that 

not only damaged and destroyed the built environment but 

resulted in the tragic loss of life. Various reports have been 

undertaken by the Federal Government and the Government 

of Puerto Rico. These include the National Hurricane Center 

Tropical Cyclone Report for Hurricane Maria, which stated 

that sixty-five people are known to have been killed directly 

or indirectly by Hurricane Maria (Pasch, Penny, and Berg 2018) 

and three indirectly by Irma (Cangialosi, Latto, and Berg 2018). 

On August 28, 2018, the Government of Puerto Rico adopted 

an official death toll for Hurricane Maria of 2,975 (Santiago, 

Schoichet and Kravarik 2018) based on a study conducted by 

researchers at George Washington University (Santos-Burgoa, 

et al. 2018). The MAT did not investigate the loss of life associated with the hurricanes but has provided the above 

information as the best available at the time of the release of 

this report.
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1.3 History of Previous Hurricanes and Mitigation

Hurricanes Irma and Maria were only the most recent significant storms to have affected Puerto 

Rico in the past 100 years. According to the USGS, other notable hurricanes that impacted Puerto 

Rico include Hurricanes San Ciriaco (1899), San Felipe (1928), San Nicolas (1931), San Ciprian 

(1932), Santa Clara (1956), Federico (1979), Hugo (1989), Georges (1998), and Irene (2011). Figure 

1-11 represents the tracks of historical hurricanes impacting Puerto Rico. The figure shows 28 

hurricanes in 166 years, for an average of more than one hurricane every six years.

Figure 1-11: Hurricanes in Puerto Rico since 1851, color-coded by Saffir-Simpson hurricane wind speed 

category. Data source: NOAA (2018).

1.3.1 Hurricane Hugo

On September 18, 1989, Hurricane Hugo crossed the Puerto Rican islands of Vieques and Culebra 

as a Category 4 hurricane, impacting the municipalities of Fajardo and Luquillo at the easternmost 

tip of Puerto Rico (Figure 1-10). Maximum winds over Vieques were estimated at 132 mph (212 kph), 

with a gust of 170 mph (273 kph) measured from a ship in Culebra’s harbor and sustained winds of 

98 mph (158 kph) measured at Roosevelt Roads Naval Station in Ceiba (National Weather Service 

1990). At that time, Hugo was the strongest hurricane to hit Puerto Rico since the 1960s.

Hurricane Hugo caused loss of life and great damage to the infrastructure of eastern Puerto Rico, 

including a large amount of damage to San Juan. Thirty thousand people were made homeless. 

Eighty percent of wooden buildings on Culebra and Vieques were destroyed. Damage to property 

is estimated to have been roughly $1 billion in Puerto Rico, not adjusted for inflation (Bureau of 

Labor Statistics 2018, National Weather Service 1990, Schwab 1994). Electrical distribution lines, 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 1-13

INTRODUCTION

telephone systems, water supplies, and transportation systems all were hard hit (Bush and Marshall 

1994). 

A 1991 American Society of Civil Engineers (ASCE) symposium paper stated that many of the repairs 

and reconstruction performed in Puerto Rico after Hugo were executed according to preexisting 

practice, repeating mistakes in design and construction that had been made before the hurricane 

(Rodriguez, Pesquera, and López 1991).

1.3.2 Hurricane Georges

Hurricane Georges made landfall in Puerto Rico on the evening of September 21, 1998, as a 

Category 2 hurricane with maximum sustained wind speeds of 115 mph (185 kph) (Guiney 1999) 

and traveled directly over Puerto Rico in an east-west direction (Figure 1-11). Though Georges did 

not match the intensity of Maria at landfall, it had devastating effects on an array of building types 

and infrastructure. Over 30,000 homes were destroyed, and an additional 100,000 experienced 

major or minor damage. Approximately 80 percent of the 3.8 million residents were left without 

power and water. Damage in Puerto Rico exceeded $2 billion, not adjusted for inflation2 (DHSOIG 

2015, NOAA 1999). 

Following Hurricane Georges, FEMA deployed a Building 

Performance Assessment Team (BPAT), a precursor of the 

MATs, to evaluate damage and compile lessons learned for 

future mitigation (Figure 1-12). This team of architects, 

engineers, planners, insurance specialists, and floodplain 

management specialists traveled to Puerto Rico for field 

investigations focusing on facilities ranging from singlefamily homes to critical facilities. The resulting BPAT Report 

(FEMA 1999) detailed recommendations for updated

building codes and regulations, training and continuing 

education, and mitigation techniques for critical facilities 

and residential buildings. The report also recommended a 

study on electrical power distribution. 

As with the current MAT process, the goals of the Hurricane 

Georges BPAT were to observe damage and provide

conclusions and recommendations to help in recovery

operations, reducing building vulnerabilities and increasing 

community resilience. Figure 1-12: FEMA BPAT Report for 

Hurricane Georges (FEMA 339 1999).

2This represents approximately $3 billion in inflation-adjusted September 2017 dollars (Bureau of Labor Statistics 

2018). 
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Most structural damage observed by the BPAT after Georges was to low-rise residential buildings 

(Figure 1-13). Many of these were informally constructed homes3 not designed or constructed to 

current building standards. Wood-framed buildings in general were found to perform poorly and 

made up a significant portion of damage caused by severe winds. The lack of proper wood-framed 

construction techniques did not provide adequate load path connections and lowered building 

survival odds. Failures often occurred at connection points, often near the roofline. Code-compliant 

houses typically sustained limited structural damage from Georges’s winds, which were below design 

speeds. 

Figure 1-13: Examples of observed damage by the BPAT after Hurricane Georges in 1998. Source: (FEMA, 

1999a).

In general, reinforced concrete and concrete masonry unit (CMU) buildings, which have strong 

continuous load path connections between the roof, wall system, and foundation, sustained limited 

structural damage from Georges. These buildings typically have flat roofs and significant steel 

reinforcement, helping them resist wind and flood loads. When damage was observed to concrete 

and CMU buildings, it was usually roof damage to those buildings with wood-framed roof structures 

and not damage to the concrete itself.

Some concrete houses with CMU infill panels were found susceptible to future seismic activity. 

These buildings had first floors supported by narrow concrete or CMU columns. Such instability 

posed a significant risk of collapse in the event of an earthquake. The BPAT recommended 

3Following local usage in Puerto Rico, this report uses the term “informal” to refer to buildings not permitted or 

built to contemporary building codes and standards (Section 2.3.4). The Hurricane Georges BPAT Report uses 

the term “self-built” for these buildings.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 1-15

INTRODUCTION

addressing seismic vulnerability along with hurricane-related hazards. Unfortunately, informal 

construction practices remain a concern in the Commonwealth.

Roof covering damage was a common occurrence following Hurricane Georges. Corrugated roofing 

systems frequently blew off their framing, though in some instances the framing failed first. The 

level and location of damage depended upon the type of connections and specific construction 

pattern of the roof covering. Exposed concrete roof types performed well against winds but suffered 

occasional leaks during the storm. Liquid-applied membranes over concrete roof decks performed 

well and suffered little wind or water damage; this was generally the best-performing option. Builtup membranes were observed to have lifted and peeled near the corners but to have generally 

stayed intact. Most built-up membranes were in low-wind-speed areas, so the overall performance 

could not be assessed. Both tile and built-up aggregate roof coverings sustained damage, either 

from uplift or missile impact. This damage was particularly concerning, as aggregate debris could 

become projectiles, causing injury or damaging other buildings.

BPAT investigators noted several instances of mitigation for wind hazard, primarily frame connection 

hardware (hurricane clips) installed by some residents after hurricanes in 1995 and 1996 (Figure 

1-14). Such mitigation measures were only partially implemented in the observed buildings. 

Figure 1-14: Frame 

connection hardware 

(hurricane clips) 

installed in a woodframed house on 

Culebra. Source: FEMA 

(1999a, 52).

Flooding from Georges damaged buildings of all types. Flooding typically caused wetting of the 

building and its contents but little structural damage. Reinforced concrete and CMU homes could be 

dried out and cleaned off easily and made habitable in a relatively short period of time. Occasional 

foundation damage was observed, particularly where buildings were sited close to coastlines or 

riverbanks (Figure 1-15).
1-16 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

INTRODUCTION

Figure 1-15: Example of 

damage to floodplain 

development observed 

by BPAT after Hurricane 

Georges in 1998. 

Source: FEMA (1999a, 

30). 

Damage observed to mid- and high-rise commercial buildings was limited. These buildings were 

usually steel-framed or reinforced concrete construction and engineered by design professionals. 

Generally, the damage that did occur was to non-structural elements, such as glazing, curtain walls, 

interior walls, and finishes, and in many cases involved wind-driven rain. 

Most of the residential buildings damaged during Georges were built without proper construction 

practices, siting, building permits, or design services. These informally constructed houses were 

not constructed to the guidelines prescribed in Puerto Rico’s Planning Regulation 7, which was 

amended in 1987 to reference the 1982 Uniform Building Code (UBC), more than ten years 

before Georges. The BPAT found code violations and unregulated construction due to overlooked 

provisions in existing statutes, regulations, policies, and practices governing development. These 

deviances accounted for significant failures in wind-damaged houses. Informal construction in 

Puerto Rico is discussed further in section 2.3.4 of this report.

Additional damage resulted from a lack of adherence to Planning Regulation 13, which enacted 

NFIP-compliant standards of floodplain management, but which was inconsistently implemented. 

Buildings were built in the floodplain with limited oversight and frequently without having been 

designed for relevant floodplain requirements. The BPAT notes that a 1998 Community Assessment 

Visit conducted by FEMA Region II, Caribbean Area Division, concluded that many buildings within 

the floodplain were at risk of flooding due to these violations and alterations without permits. Many 

buildings within the floodplain were inundated during Georges and sustained significant damage.

1.3.2.1 BPAT Mitigation Recommendations

The Government of Puerto Rico took swift action in the aftermath of Georges to address identified 

flaws in the building sector. The Regulations and Permits Administration (Administración de 

Reglamentos y Permisos [ARPE]), the permitting body at that time, repealed Planning Regulation 

7 and adopted regulations based on the 1997 UBC as an emergency action. The previously adopted 

1982 UBC was found to significantly under-predict loads and new provisions of the 1997 UBC 

provided for wind speedup due to topography and new loads for windows, doors, and roofs. The 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 1-17

INTRODUCTION

BPAT noted that while recommended, an updated code was only part of an effective mitigation 

strategy. Much of the observed damage could have been avoided had buildings initially complied 

with the older code. To help address those concerns, the government of Puerto Rico worked with 

FEMA to develop a strategic plan to offer training on the new provisions. 

The BPAT Report outlined a series of recommendations to advance mitigation priorities. These 

recommendations included the following overarching goals:

● Design buildings to new building regulations.

● Permit, build, and inspect new buildings to meet the new regulations.

● Retrofit existing buildings to make their envelopes more resistant to breaching in future 

windstorms.

● Take precautions in areas with known hazards, such as floods and landslides. 

These guiding principles were further detailed for practical action. For example, for wind hazards, 

mitigation efforts prior to Georges encouraged metal framing connectors between rafters and 

bearing walls. Where implemented, however, similar reinforcement had not been provided for 

connections between the metal roof panels and wood nailers, or between the nailers and rafters. 

The result was homes with only partially connected load paths. These houses typically sustained 

significant roof covering damage, which led to further damage to the interiors and contents. 

Mitigation recommendations by the BPAT suggested a total load path strategy and prioritizing the 

most vulnerable components of the load path first. If a complete load path was not possible, the roof 

covering typically fails first and should be strengthened to reduce losses to the interior.

The bulk of BPAT recommendations were related to training, code adoption, and code enforcement. 

The emergency adoption of the 1997 UBC was an important first step, but further work was needed 

to ensure that it would be effective and comprehensively implemented. The BPAT recommended 

several local amendments to the 1997 UBC: provisions for roofing uplift testing, prescriptive design 

of metal roofing, requirements for non-structural envelope repairs, the adoption of the Uniform 

Code for the Abatement of Dangerous Buildings (ICC© 1997), requirements for re-roofing, 

requirements for wood preservative treatments, and provisions for wind-resistance and missile 

impact testing for glazing. It also recommended aggressive enforcement of the new code throughout 

permitting and inspection to encourage a culture of regulatory compliance.

For buildings within the floodplain, the BPAT recommended renewed enforcement of the NFIP 

standards found in Planning Regulation 13. As adopted by Puerto Rico, these standards applied to 

residents in the floodplain both with and without flood insurance. Yet, it was common for residents 

to enclose ground-floor areas of buildings or otherwise add improvements that did not comply with 

NFIP regulations. The BPAT recommended continued efforts to encourage participation in the 

NFIP to increase compliance and reduce risk. At the time of the BPAT, about 25 percent of the 

population in the Special Flood Hazard Area (SFHA) had flood insurance. 

Finally, the BPAT stressed the importance of education and implementation to support the 

adoption of the new provisions. This was to include hiring and training additional ARPE staff. 

Multiple training needs were identified for ARPE staff, design professionals, technicians, builders, 

contractors, and public policy decision-makers. ARPE, the Colegio de Ingenieros y Agrimensores, 
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INTRODUCTION

the Colegio de Arquitectos, the International Conference of Building Officials (ICBO), and FEMA 

worked together to develop a training schedule to explain the new provisions to such audiences.

FEMA-funded mitigation programs enacted after Hurricane Georges included retrofitting of 

existing buildings by Project Impact and replacement of vulnerable buildings by the New Secure 

Housing Program (NSHP; Nuevo Hogar Seguro).

1.3.2.2 Project Impact Culebra

Project Impact was a FEMA program in existence from 1997-2001 that supported and facilitated 

community preparations for natural disasters. The Puerto Rican island of Culebra was nominated 

by FEMA to participate in Project Impact in June of 1998, three months before Hurricane Georges, 

and Project Impact Culebra was actively participating later that year. In March 1999, Culebra was 

designated a Disaster-Resistant Community under Project Impact. As a result, FEMA provided 

$500,0004 for mitigation including the installation of hurricane clips and straps in existing wood 

buildings and waterfront restaurants and the installation of hurricane shutters and hurricane 

resistant windows for several community facilities: the Culebra Community Health Center, Municipal 

Building, Municipal Library, the Elderly Center, and the Multiple Use Center (FEMA 1999b). The 

Hurricanes Irma and Maria MAT visited the Municipal Building and Culebra Community Health 

Center. Some mitigation measures were observed, and structural and opening performance at these 

facilities was generally good (Chapter 5).

1.3.2.3 New Secure Housing Program

The New Secure Housing Program (NSHP; Nuevo Hogar Seguro) was established on October 15, 

1998, by executive order of then Governor of Puerto 

Rico Pedro Rosselló. Its purpose was “to replace or 

rebuild low-income housing stock the disaster damaged 

while undertaking permanent measures to mitigate 

against damage from similar future events” (DHSOIG 

2015 p2). Hurricane Georges had damaged 100,000 

homes and left more than 30,000 families homeless. 

The NSHP received funding from two FEMA programs, 

the FEMA Hazard Mitigation Grant Program and 

FEMA Disaster Assistance for Unmet Needs (DHSOIG 

2015, FEMA 2000). The total cost claimed by the Puerto 

Rico Department of Housing (PRDOH; Departamento 

de Vivienda) was $184 million5 (DHSOIG 2015).

The program had two parts. The “on-site component” 

involved replacing vulnerable buildings at existing 

sites. The “off-site component” involved acquiring and 

removing damaged or destroyed homes in highly flood-, Figure 1-16: Cover of the 1997 UBC, adopted 

by Puerto Rico after Hurricane Georges.

4This is approximately $750,000 in inflation-adjusted September 2017 dollars. 

5This is approximately $277 million in inflation-adjusted September 2017 dollars. 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 1-19

INTRODUCTION

seismic-, and landslide-prone sites, and replacing them at new sites. New homes were constructed in 

accordance with the 1997 Uniform Building Code (UBC) (Figure 1-16).

Work to replace homes began in 2003 and finished in 2011. In total, the program built 1,647 housing 

units, 66 on-site and 1,581 off-site (as defined above), in a total of 15 municipalities in Puerto Rico. 

The municipalities were Arroyo, Caguas, Canóvanas, Coama, Dorado, Guayama, Jayuya, Juana Diaz, 

Juncos, Morovis, Ponce, Santa Isabel, Toa Baja, Vega Alta, and Villalba (Figure 1-17). The flagship 

site was Campanilla Farm in Toa Baja, where 223 concrete homes were built (DHSOIG 2014, FEMA 

2000a). 

The MAT visited several NSHP homes throughout Puerto Rico. Performance of these codecompliant concrete buildings (Chapter 3) in Irma and Maria was generally very good.

Figure 1-17: Locations of New Secure Housing Program Communities.
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INTRODUCTION

1.3.3 Other FEMA Hazard Mitigation

On August 22, 2011, Tropical Storm Irene became Hurricane Irene while passing over Puerto Rico 

(Figure 1-10). The hurricane continued away from the island to the northwest. Sustained winds 

of 51 mph (82 kph) (66 mph [106 kph] 3-second gust) were recorded in Vieques. Irene produced 

heavy rain in Puerto Rico, with a maximum rainfall of 22 inches (56 centimeters) in Gurabo Abajo, 

Juncos. The northeast portion of the island experienced major flooding (Avila and Cangialosi 2011).

Following Irene, several hazard mitigation projects were carried out in Puerto Rico. Fifteen public 

buildings received wind retrofits including storm shutters, mostly in San Juan. Properties were 

acquired to mitigate riverine flooding and erosion hazards in Cayey and San Sebastián, respectively.

In response to severe storms, flooding, and mudslides in May 2001 (FEMA DR-1372) (FEMA 2012), 

a FEMA HMA grant was awarded for the installation of storm shutters on fire stations throughout 

Puerto Rico. Forty-five stations were equipped with impact-resistant shutters at a total program cost 

of $237,8386 (FEMA 2018a, FEMA 2018b). Following severe storms and flooding in 2009 (FEMA 

DR-1798), 23 additional fire stations, largely in southern municipalities, were equipped with 

storm shutters at a total program cost of $124,0937 (FEMA 2008b, FEMA 2018a, FEMA 2018b). 

Performance of fire station shutters in Irma and Maria was generally good. Detailed observations 

are presented in chapter 5.

1.4 FEMA Mitigation Assessment Team

FEMA conducts building performance studies after unique or nationally significant disasters 

to better understand how natural and manmade events affect the built environment. A MAT is 

deployed when FEMA believes the findings and recommendations derived from field observations 

will provide design and construction guidance that will improve the disaster resistance of the built 

environment in the affected State or region and will be of national significance to other disasterprone regions. FEMA bases its decision to deploy a MAT on preliminary information such as the 

following:

● Magnitude of the expected hazards

● Potential type and severity of damage in the affected areas

● Pre-storm site conditions, such as the presence of older housing stock and aging infrastructure

● Potential value of study results to the rebuilding effort

● Potential to gain strategic knowledge related to improving building codes, standards, and 

industry guidance, potentially on a national level;

● Potential to gain feedback on the effectiveness of previous FEMA grants

6This is approximately $330,000 in inflation-adjusted September 2017 dollars. 

7This is approximately $140,000 in inflation-adjusted September 2017 dollars.
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INTRODUCTION

● Potential to gain pertinent information on key engineering principles and practices that FEMA 

promotes in published guidance and best practices documents

The MAT studies the adequacy of current building codes, local construction requirements, 

building practices, and building materials based on the damage observed after a disaster. Lessons 

learned from the MAT process are communicated to policy makers, stakeholders, and the public; 

for this event, the work products include six Recovery Advisories (Appendix D) and the following 

comprehensive MAT Report. This report is intended to aid communities in improving the disaster 

resilience of buildings through repairs, improvements, and new construction.

1.4.1 MAT Composition

The MAT for Hurricanes Irma and Maria in Puerto Rico was composed of engineers, architects, 

floodplain managers, and other experts with diverse training and experience from a range of 

institutions:

● FEMA Headquarters and Regional Office staff

● Housing and Urban Development staff

● National Institute of Standards and Technology staff

● Construction and building code industry experts

● Local and national design professionals, including engineers and architects

● FEMA specialists deployed to the Puerto Rico Joint Field Office (JFO)

Team members included structural and civil engineers; coastal engineers; architects; floodplain 

managers; building code, wind design, and critical facilities experts; an aerial drone operator; and 

FEMA specialists. Members of the MAT are listed at the front of this document.

The MAT report is divided into these main study areas: 

● Building codes, standards, and regulations

● Residential and low-rise buildings

● Schools and shelters

● Hospitals and other critical facilities

● PV systems and solar water heaters

Each specific study area included field visits to numerous locations throughout Puerto Rico, 

including the islands of Culebra and Vieques.

1.4.2 Involvement of Commonwealth and Local Agencies

FEMA encouraged the participation of Commonwealth and municipal officials, as well as resident 

experts in the assessment process. The MAT met with various Commonwealth and municipal 
1-22 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

INTRODUCTION

officials, as well as facility managers and engineers at critical facilities. These officials were able to 

provide insight into damage within their communities as well as recommending specific geographic 

areas to be visited by the MAT. The MAT also coordinated with specialists at the Puerto Rico JFO. 

The involvement of local agencies was key to the effectiveness of the MAT and offered several 

significant advantages:

● Improving the MAT’s understanding of local building processes, including permitting and 

construction practices.

● Assisting the MAT in developing recommendations that are economically and technically 

feasible and can be readily implemented by communities and stakeholders. 

● Facilitating communication among Federal and Commonwealth government entities and the 

private sector.

● Improving the Commonwealth’s understanding of the MAT’s observations and 

recommendations so it can implement them for improved building and community resilience.

1.4.3 Pre-MAT

FEMA deployed a Pre-MAT consisting of two sub-teams to Puerto Rico on October 24-October 26, 

2017. The purpose of the Pre-MAT was to perform initial reconnaissance and determine areas of 

focus for further investigation by the MAT. Following the Pre-MAT, an outbrief was provided to 

FEMA, Commonwealth officials, and other stakeholders summarizing preliminary observations 

and proposing areas of study for the MAT. Pre-MAT damage observations were supplemented by 

desktop analyses including a review of aerial imagery taken by NOAA and the U.S. Civil Air Patrol. 

Review of this imagery gave additional insight about damage in areas that the Pre-MAT was unable 

to visit due to time constraints.

Key areas of focus by the Pre-MAT included the performance of residential buildings, commercial 

buildings, critical facilities, and buildings built following Hurricane Georges. The Pre-MAT 

also considered the effectiveness of mitigation programs and recommendations provided in the 

Hurricane Georges BPAT (FEMA 1999a) as well as the performance of power and communication 

systems, specifically PV systems. 

1.4.4 Structure Types Assessed

The structures selected by the MAT for damage assessment included single-family, multifamily, lowrise, and mid-rise buildings, as well as schools, shelters, hospitals, public buildings, police and fire 

stations, PV arrays, and solar water heaters. The MAT visited coastal and riverine floodplains and 

urban, suburban, coastal, and mountainous areas. 

1.4.5 MAT Field Deployment

The MAT deployed to Puerto Rico in four sub-teams, with the first group deployed December 5, 

2017, and the rest deployed December 11. Each MAT sub-team consisted of 5-6 members, and each 

focused on specific items:
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 1-23

INTRODUCTION

● The Building Code, Permitting, and Residential Sub-Team (Dec. 5–9) met with 

Commonwealth and municipal officials involved with the building codes, floodplain 

ordinances, and local policies governing construction in various municipalities on the main 

island of Puerto Rico.

● The Coastal and Riverine Flooding Sub-Team (Dec. 11–15) met with municipal officials and 

observed coastal, riverine, and critical facility sites on the main island of Puerto Rico.

● The Wind Sub-Team (Dec. 11–15) met with Commonwealth and municipal officials, and 

reviewed wind performance of residences, schools, critical facilities, and PV systems on the 

main island and Vieques.

● The Support and Drone Sub-Team (Dec. 11-15) provided support for the flood and wind 

groups. It also provided drone reconnaissance to access sites and perspectives that were either 

unsafe or impractical to physically access.

As the MAT sub-teams performed site visits, additional or alternative sites were added after reviewing 

on-the-ground conditions or based on information from Commonwealth and municipal officials. 

Officials, facility operators, building owners, and residents were interviewed regarding specific local 

conditions experienced during the storms, performance of buildings, knowledge of mitigation 

actions, and progress of recovery. 

1.5 Summary of MAT Observations

Hurricane Irma resulted in damage to residential buildings and utility infrastructure throughout 

Puerto Rico, even though Irma did not make landfall in the Commonwealth. Two weeks later, 

Hurricane Maria made landfall, causing significant damage throughout Puerto Rico. The 

combination of high winds, heavy rainfall, and storm surge resulted in damage across a wide variety 

of building types. Levels of damage varied widely by building type, building construction quality, 

and geographical location.

1.5.1 Residential and Low-Rise Buildings

A wide range of construction quality was seen in residential buildings. In general, permitted wood 

and concrete homes with properly-detailed connections performed well. Informally constructed 

homes often performed poorly due to a combination of materials used, poor or nonexistent 

connections, and location. 

Many buildings, formal and informal, experienced large amounts of water infiltration due to 

damaged roof coverings, damaged openings (windows and doors), or wind-driven rain entering 

through unsealed openings. It was noted that many opening protection systems failed due to being 

in poor condition and being at the end of their useful life.

The MAT also noted wind damage related to topography. There were groupings of failures in larger 

residential settings where damage was likely caused or intensified by wind speed-up over topographic 

features. Failures due to rainfall and flooding were also noted. Buildings adjacent to channels or 
1-24 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

INTRODUCTION

ridges experienced failures due to stream bank erosion or landslides. There was damage noted 

from both inundation and velocity flooding. Buildings on the coast were damaged from both storm 

surge inundation and collapse due to coastal erosion.

1.5.2 Schools and Critical Facilities

Schools and critical facilities, including hospitals, generally performed well structurally during 

Hurricanes Irma and Maria. However, several common failures were observed and collectively these 

buildings performed no better than commercial buildings overall. Water intrusion into buildings 

from roof covering or rooftop equipment failures was a common observation. Additional water 

intrusion occurred due to failures of unprotected or inadequately protected openings and at 

unsealed openings. Water intrusion for these buildings was especially problematic, as it resulted in 

loss of use of portions of the buildings.

1.5.3 Photovoltaic Arrays and Solar Water Heaters

PV arrays and solar water heaters have become very common in Puerto Rico and play an important 

role in providing electrical service and hot water. Solar water heaters are required through the 

building code in new residential construction in the Commonwealth. The performance of solar 

equipment including ground-mounted and rooftop systems varied widely based on factors including 

type, attachment, and location.

1.5.4 Flood Zones

Flood risk in Puerto Rico varies widely with geographic location. Coastal areas are subject to storm 

surge flooding. These include VE Zones, which are coastal areas subject to high-velocity wave action; 

AE Zones, which are coastal areas subject to wave action that is less severe than in VE Zones; and 

Coastal A Zones (CAZs), which are portions of the AE Zone landward of the VE Zone and seaward 

of the inland limit of the 1.5-foot (0.5-meter) breaking wave height during the base flood event. 

For the first time in Puerto Rico, the CAZs have been depicted on post-storm Advisory Mapping, 

adopted on an emergency basis in April 2018. In addition to AE and VE Zones along the coast 

of Puerto Rico, there are inland riverine A and AE Zones. There are many areas not located in a 

designated flood zone that are nevertheless at high risk of localized flooding. These locations, which 

may be as small as a single property, may flood due to runoff from local terrain, poor building 

siting, or poor local drainage. Additionally, many buildings in mountainous regions are at risk from 

landslides in heavy rains. Many buildings sited on steep slopes were observed to be at risk of collapse 

from landslides.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 2-1

2

HURRICANES

IRMA AND MARIA

IN PUERTO RICO

MITIGATION ASSESSMENT TEAM REPORT

Building Codes, Standards, 

and Regulations

A combination of building codes and floodplain management 

ordinances determine the requirements that govern construction 

in the Commonwealth.

2.1 History of Building Codes in Puerto Rico 

Planning Regulation 7 was adopted by the Governor as Puerto Rico’s building code in 1968 

(Figure 2-1) under the authority of Law No. 168 of 1949. In 1975, a new agency, the Regulation and 

Permitting Administration (Adminstración de Reglamentos y Permisos), commonly referred to by 

its Spanish acronym, ARPE1, was created to regulate permitting in the Commonwealth. In 1987, 

ARPE amended Planning Regulation 7 to include provisions on requirements for minimum design 

loads acting on structures based on the 1982 Uniform Building Code (UBC), requirements for all 

new construction to be seismic-resistant, and a new basic design wind speed of 110 mph (177 kph) 

fastest-mile (125 mph [201 kph] 3-second gust).

1Puerto Rico’s building code is currently administered by the successor entity to ARPE, the Permits Management 

Office (Oficina de Gerencia de Permisos [OGPe]).
2-2 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

BUILDING CODES, STANDARDS, AND REGULATIONS

Figure 2-1: Timeline for the Puerto Rico Building Code.

After Hurricane Hugo in 1989, much of the reconstruction did not follow hazard-resistant practices, 

posing additional risk to structures in future storms (Rodriguez, Pesquera, and López 1991). Nine 

years later, after Hurricane Georges in 1998, although mandatory practices for different principal 

construction types were required by Planning Regulation 7, the guidelines for new construction, 

accounting for wind and seismic loads, had not been consistently followed or enforced. The BPAT 

concluded that a majority of the damage caused by Hurricane Georges was directly related to design 

inadequacies and deficient enforcement of Planning Regulation 7 and poor construction quality of 

informally constructed homes. 

Immediately following Hurricane Georges, ARPE initiated changes to increase public safety and 

reduce property damage. The first step took place in December 1998 when the Government of 

Puerto Rico passed an emergency regulation that repealed Planning Regulation 7 and replaced it 

with the 1997 UBC with local amendments. The 1997 UBC would serve as the Puerto Rico Building 

Code (PRBC) until 2011.

In January 1999, ICBO conducted a peer review of ARPE to assess the needs of the Commonwealth. 

ARPE requested the peer review to help respond effectively to post-storm reconstruction activity 

in the wake of Hurricane Georges, as well as anticipated future construction. The ICBO review 

provided recommendations for improved policies, procedures, and training.

Following the peer review, ARPE and FEMA established a comprehensive plan to provide necessary 

training and briefings for ARPE staff, design and construction groups, the banking and mortgage 

industries, and policymakers. The goal of the plan was to provide a smooth transition to updated 

building codes. ARPE prepared improved building and enforcement regulations for the Certification 

and Building Board of Puerto Rico which was under proposed legislation at the time. One of the 

Board’s projected responsibilities was to adopt updated building regulations, including the formal 

adoption of the 1997 UBC. The Board was never created, but in December 1999, Puerto Rico did 

adopt the 1997 UBC formally, with amendments revised by ARPE (FEMA 1999).
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 2-3

BUILDING CODES, STANDARDS, AND REGULATIONS

In 2007, Puerto Rico attempted to develop a process to update its building codes; however, the effort 

was unsuccessful, with no updates taking place. Two years later, a Construction Codes Committee, 

established by the Permits Office, reviewed and implemented a transition from the existing 1997 

UBC to a subset of the International Code series (I-Codes) published by the International Code 

Council (ICC©). The Committee was comprised of representatives from the construction industry, 

architects, engineers, and representatives of regulatory government agencies, who attended 

several seminars to become familiar with the 2009 I-Codes. The committee evaluated proposed 

amendments for three days with the goal of revising the PRBC based on the 2009 I-Codes.

In 2009, the Permits Management Office (Oficina de Gerencia de Permisos), commonly referred 

to by its Spanish acronym, OGPe, was created as the successor to ARPE to enforce regulations 

including those on land use planning, licensing, inspections, certification, and permitting. Besides 

assuming the duties of ARPE, OGPe took on a unifying, coordinating role to enforce permitting 

regulations developed by PRPB (PRPB Audit and Compliance Bureau 2017).

2.2 Puerto Rico Building Code 

The 2011 PRBC is a compilation of I-Codes adopted with local amendments. The I-Codes adopted 

include the 2009 editions of nine of the I-Codes:

1) International Building Code

2) International Energy Conservation Code

3) International Existing Building Code

4) International Fire Code

5) International Fuel and Gas Code

6) International Mechanical Code

7) International Plumbing Code

8) International Private Sewage Disposal Code

9) International Residential Code 

The PRBC is implemented to “provide minimum requirements to safeguard the public health, safety 

and general welfare of the occupants of new and existing buildings and structures” (PRBC 2011, 3). 

Local amendments included a municipality-based map for IBC© “1613.5 Seismic Ground Motion” 

that used the most conservative ground acceleration within the municipality. For the IRC©, a local 

amendment to “R301.2.12 Protection of Openings” expanded the design wind speed allowance for 

prescriptive-based wood structural panels for wind-borne debris region opening protection from 

130 mph (209 kph) to 145 mph (233 kph). This is a significant amendment, as all of Puerto Rico 

is within the 145 mph design wind speed for the 2011 PRBC. The 2011 PRBC became available for 

adoption and use in March of that year. 
2-4 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

BUILDING CODES, STANDARDS, AND REGULATIONS

According to the PRBC, the building codes are updated, and a new edition issued, every three years 

to incorporate new construction methods. However, no new edition of the building code has been 

adopted since the initial implementation of the code in March 2011, and it has only been amended 

once, in June 2012. Due to many advances since the 2009 I-Codes, the 2018 I-Codes incorporate 

the most up-to-date hazard-resistant provisions. In addition, Puerto Rico does not participate in 

The International Organization for Standardization’s (ISO’s) Building Code Effectiveness Grading 

Schedule (BCEGS) program, which tracks the adoption and enforcement of building codes, with 

emphasis on hazard resistance.

After the destruction of Hurricanes Irma and Maria, OGPe issued Administrative Order 2017-10 

(OGPe 2017) on December 26, which orders the establishment of a committee to revise and adopt 

the PRBC based on the 2018 I-Codes. The Committee’s focal responsibility is to “study, evaluate, 

and make recommendations regarding adopted building codes” (OGPe 2017, 2). The order allows 

for a maximum of 180 days from the Administrative Order’s issue date to establish the Committee 

and for the Committee to make the necessary recommendations. 

On May 30, 2018, the Commonwealth enacted Law 2018-109 (Law 2018-109 2018). This law directed 

the Construction Codes Review Committee to revise Puerto Rico building codes on a three-year 

cycle.

The final publication of the new PRBC is expected to occur on November 15, 2018, according 

to communications with the Puerto Rico Construction Code Adoption and Revision Committee 

(Comité para la Adopción y Revisión del Códigos de Construcción de Puerto Rico) in September 

2018. The codes proposed for adoption are the 2018 editions of 10 of the I-Codes (Planning 

Department 2018):

1) International Building Code

2) International Energy Conservation Code

3) International Existing Building Code

4) International Fire Code

5) International Fuel and Gas Code

6) International Mechanical Code

7) International Plumbing Code

8) International Private Sewage Disposal Code

9) International Residential Code

10) International Swimming Pool and Spa Code

2.3 Planning, Permitting, and Code Enforcement

Development in Puerto Rico is governed by several different bodies. The Puerto Rico Planning 

Board (PRPB; Junta de Planificación de Puerto Rico) guides development, and building permits 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 2-5

BUILDING CODES, STANDARDS, AND REGULATIONS

are administered by OGPe. Code enforcement is governed by the PRPB and some autonomous 

municipalities. 

Law 19-2017, the Permitting Reform Act, was enacted in Puerto Rico (Permitting Reform Act of 

2017). This Act consolidated Commonwealth and municipal permits in one online system to 

allow design professionals and contractors to follow a consistent set of procedures (Federal Affairs 

Administration 2017).

Puerto Rico’s floodplain management ordinance is Puerto Rico Special Flood Hazard Areas 

Regulation (Planning Regulation 13) effective January 7, 2010. Planning Regulation 13 enacted 

NFIP-compliant standards for floodplain management. Additional floodplain regulations were 

proposed by the PRPB in 2016 but not adopted; these included requiring 2 feet of freeboard for 

residential buildings and 1 foot for non-residential buildings, requiring compensatory runoff 

storage to offset losses in flood storage capacity due to development, and regulating the siting of 

critical infrastructure within the 500-year floodplain. Local floodplain management regulation in 

Puerto Rico requires a minimum of 1 foot of freeboard for residential structures. Per Planning 

Regulation 13, Section 7.03(b), non-residential structures currently have no freeboard requirement.

The 2018 I-Codes include a number of floodplain management provisions that have changed since 

Regulation 13 was issued in 2010. The two documents are currently not consistent. For example, 

Planning Regulation 13 has no freeboard requirement for commercial structures; however, 2018 

IBC© which references ASCE 24-14, requires a minimum of 1 foot of freeboard for commercial 

structures; more than 1 foot may be required, depending on the building’s Flood Design Class. 

Refer to Highlights of ASCE 24 Flood Resistant Design and Construction (FEMA 2015b) https://www.

fema.gov/media-library/assets/documents/14983 for more information.

2.3.1 Planning Board

The PRPB was created by Law No. 213 on May 12, 1942, during the governorship of Rexford G. 

Tugwell, to regulate development in the Commonwealth (PRPB Audit and Compliance Bureau 

2017). Originally known as “Puerto Rico Planning, Urbanization, and Zoning Board”, it established 

the means to systematize and organize planning. Today, the PRPB continues to guide development 

to meet current and future needs (PRPB 2010). It acts as an extension of the Governor “to design 

and formulate the short, medium and long term public policy of economic development, and the 

use of the resources of the Island” (PRPB 2017). The PRPB regulates construction, prepares maps 

of geographic limits of Puerto Rico municipalities and neighborhoods, and declares slum areas. Its 

authority allows it to address urban renewal and the elimination of slums.

Members of the PRPB are appointed by the governor of Puerto Rico and work in conjunction with 

OGPe, which issues construction permits throughout the Commonwealth. While the PRPB evaluates 

projects, including public and regional impact works, and changes in zoning classifications, OGPe 

evaluates variations in construction and use. The PRPB also serves as the lead for the NFIP State 

Coordinating Agency. 

Beginning in April 2017, the PRPB has had authority to “carry out compliance inspections and audits 

of permits granted by [OGPe] and the 17 permits office[s] of the [autonomous] municipalities” 

(PRPB Audit and Compliance Bureau 2017).
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2.3.2 Permits Management Office (OGPe)

In December 2009, the Puerto Rico Government created Act No. 161, the “Puerto Rico Permit 

Process Reform Act” as a response to the economic and fiscal crisis in Puerto Rico. The Act created 

OGPe to implement a new and efficient permit system that would boost the Puerto Rican economy 

by creating jobs in the construction industry and other sectors. OGPe replaced ARPE, which had 

governed the permitting process in Puerto Rico since its establishment in 1975.

OGPe is responsible for defining and enforcing Division I of the PRBC. This includes establishing the 

applicability of codes, defining the enforcement agencies, and processing construction documents. 

OGPe maintains the PRBC by reviewing proposed changes submitted by code enforcement officials, 

design professionals, industry representatives, and other interested parties. OGPe considers changes 

through an open code development process with updates to be promulgated every three years 

according to the PRBC.

OGPe handles permitting and inspections from a main office in San Juan and regional offices in 

Aguadilla, Arecibo, Humacao, and Ponce. Municipal officials have identified this as problematic, 

because staffing and office locations limit OGPe’s ability to inspect every project. 

2.3.3 Permitting and Enforcement at the Local Level 

While much of the permitting in Puerto Rico is done at the Commonwealth level by the PRPB 

and OGPe, municipalities may be granted a transfer of some powers to regulate construction. The 

Autonomous Municipalities Act of 1991 (“Autonomous Municipalities Act of the Commonwealth 

of Puerto Rico of 1991” 1991), since amended, defines the mechanisms by which municipalities 

may have degrees of fiscal autonomy and self-government. Section 13.012 of this Act defines five 

categories or tiers of delegation of authority. The autonomous municipalities are those at the highest 

tier, Tier 5, which have a Land Ordination Plan in effect; they may acquire powers for regulating 

construction that are otherwise reserved for the PRPB and OGPe (Puerto Rico Permit Process 

Reform Act 2009). Delegation of planning authority to a municipality requires that the municipality 

establish a Permits Office and have a territorial plan in effect, among other requirements. The 

agreement may set limitations to the delegated powers according to the municipality’s capacity. As 

of the time of preparation of this report, 18 municipalities have delegation agreements in place with 

permit offices (PRPB 2017), with some municipalities having consolidated permit offices (Table 2-1).

Table 2-1: Municipalities with Delegated Permitting Authority and Permit Offices

Aibonito * Carolina Guaynabo

Aguadilla Cayey** Humacao

Barranquitas* Cidra Ponce

Bayamón Comerío* San Juan

Cabo Rojo Coamo** Salinas**

Caguas Fajardo Villalba**

*Aibonito, Barranquitas, Comerío (ABC) Consortium, permit office in Barranquitas

** Cayey, Coamo, Villalba, Salinas (CCVS) Consortium, permit office in Cayey

Source: PRPB (2017), http://jp.pr.gov/Municipios-Tabla
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The transfer of powers to a municipality grants the power to handle, resolve, and process complaints 

and violations related to that power. It also grants the municipal agencies powers to promote 

compliance and implementation of regulations. However, the PRPB may determine that a project 

that has been referred to a municipality must be referred back to the PRPB due to possible regional 

impacts not accounted for in the plan.

As of December 2017, there were 11 Compliance Inspectors at the PRPB. These inspectors 

are responsible for compliance inspections throughout Puerto Rico. At that time, OGPe had 13 

inspectors and technicians assigned to Construction Permits and 12 to Uses Permits (PRPB Audit 

and Compliance Bureau 2017). The ICC© lists three ICC©-certified individuals in Puerto Rico 

on its website (ICC 2018), and the Association of State Floodplain Managers lists seven Certified 

Floodplain Managers (CFMs) for Puerto Rico. Most States have dozens to hundreds of CFMs 

(Association of State Floodplain Managers 2018), and more CFMs and ICC©-certified inspectors 

and technicians would be beneficial for Puerto Rico. As of the publication of this report, increasing 

the number and training of permitting staff is the goal of ongoing HMA-funded efforts in Puerto 

Rico.

2.3.4 Formal and Informal Construction 

Construction in Puerto Rico is commonly described as either formal or informal. Formal construction 

typically follows adopted building codes and standardized practices. It is officially permitted either 

by OGPe or by an autonomous municipality. Formal construction is overseen by, and requires final 

approval from, a professional engineer or registered architect. In contrast, informal construction is 

often “self-built” without proper permitting and without design professional supervision during the 

construction process. Nearly half of Puerto Rican homes were built or renovated through informal 

construction (PRDV 2018). In general, the prevalence of informal construction is a major challenge 

to the effective implementation and enforcement of building codes.

Based on data from the PRDOH, there are currently 1.4 million housing units in Puerto Rico, with 

1.1 million of these units occupied. A report for the PRDOH cited an estimate that 45–55 percent of 

all housing in Puerto Rico is informal (PRDV 2018). Only 1 percent of housing stock was built after 

2010, compared to a national average of 4.2 percent.

Reasons for the existence of informal construction prior to Hurricanes Irma and Maria included a 

lack of adequate resources to enforce and remediate unpermitted construction and OGPe’s current 

exemption from design professional certification requirements for certain projects less than $6,000 

(PRPB not dated).

Administrative Order 2017-07, issued on October 5, 2017 (OGPe 2017) enabled certain aspects 

of reconstruction, replacement, or repairs following Hurricanes Irma and Maria to commence 

without the requirement of a government-issued permit. The order was valid for 120 days from its 

issuance. While issued with the intent of encouraging rapid reconstruction and helping individuals 

reoccupy their homes and businesses after Irma and Maria, the order allowed unpermitted work to 

be performed and may have contributed to the continued prevalence of informal construction in 

Puerto Rico.
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Informal construction may be non-compliant with some or all of the building code, zoning, or title 

requirements. Aspects of informal construction practices may be additive; for example, a home with 

no title may have been built in a high-risk location in a manner not compliant with the building 

code. The discussion below is provided to clarify the use of the terms.

2.3.4.1 Informal Construction: Building Codes, Floodplain Management Ordinance, and Permitting

The building code provides the minimum design criteria for buildings and structures. The 2011 

PRBC requires that a building be designed by a qualified design professional to meet criteria set 

out in the code, be permitted, be built to the design, and be inspected. Informal construction with 

respect to building codes, floodplain management ordinance, and permitting does not meet the 

requirements of the PRBC and/or Planning Regulation 13 for design, permitting, construction, 

and/or inspection. Informal construction may have some code-compliant design features when 

builders have previous construction experience. However, building codes are amended and 

changed over time; therefore, building according to techniques learned by example is unlikely to 

produce buildings meeting modern standards for hazard resistance. Experience has shown such 

construction to vary widely in construction quality.

2.3.4.2 Informal Construction: Zoning

Informal construction that does not meet zoning requirements for the municipality will 

require either a variance to the zoning code or some form of remediation if it is to be brought 

into compliance. For example, residential buildings built too closely according to the code may 

be granted a variance if the spacing is determined to be acceptable or if some measure is taken 

to protect the two buildings. The municipality may require some adjustment in the buildings to 

maintain fire resistance, ensure privacy, or satisfy other requirements.

In the event a home has been built in an area where the risks of landslides or flooding is too great, 

issuing a variance may not be possible, as continued occupancy of a home in those areas places the 

residents at risk. In those cases, the municipality could condemn2 the property.

Effectively implementing zoning and land use requirements in a municipality requires the 

development and enforcement of a land use plan. Such an effort requires technically skilled 

planners as well as political support for enforcement of zoning, planning, permitting, design, and 

construction requirements. 

2.3.4.3 Informal Construction: Title

Informal construction that lacks title is possibly the most difficult issue to resolve, as the building 

owner may not have the legal right to occupy the underlying land. In those cases, the owner of the 

home would need to secure title to the land. This may require some type of subdivision of the land 

as there is little chance a single, platted lot was developed without title. In the case of land owned by 

2Condemnation is a process in which a structure is deemed unsafe for habitation. Residents are required to 

relocate from a condemned structure.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 2-9

BUILDING CODES, STANDARDS, AND REGULATIONS

the municipality or Commonwealth, there might be additional procedural requirements associated 

with transferring publicly owned land to private ownership.

Municipal officials told the MAT that Puerto Rico’s banking industry incentivizes homeowner 

compliance with the building code by requiring permit information for mortgages and mortgagebacked transactions, including home equity loans and reverse mortgages. These officials stated 

that the PRPB and OGPe have considered developing programs based on these industry practices 

to work with homeowners to retrofit existing informally constructed buildings and issue permits 

retroactively for those now in compliance with the building code. A building code inspector could 

inspect the property to identify the issues requiring correction and determine whether it would be 

feasible to bring the building into compliance.

2.4 Design Wind Speeds

In some areas of the Commonwealth, Maria’s wind speeds approached the prescribed wind speed 

design requirements of the 2018 International Building Code (IBC©) and 2018 International 

Residential Code (IRC©), which reference design wind speeds found in the ASCE standard Minimum 

Design Loads and Associated Criteria for Buildings and Other Structures (ASCE 7-16). 

Design winds speeds for Puerto Rico can be found on maps in ASCE 7. It should be noted that 

comparing design wind speeds used in building codes and standards with observed or estimated 

wind speeds from a hurricane is not straightforward. For a direct comparison of one wind speed 

to another, they must both have the same basis in terms of averaging time, height, and terrain. 

Because the wind speed definitions and related criteria used in the building codes and standards 

have undergone two major changes in recent decades, design wind speeds from older codes and 

standards cannot be directly compared to those in newer versions.

Hurricane wind speeds are often reported using the maximum sustained surface wind speed 

(peak 1-minute sustained wind) at the standard meteorological observation height of 33 feet (10 

meters) above ground over open water, although peak gusts and wind speeds at other heights 

are also reported. Prior to the publication of ASCE 7-95 (ASCE 1995), the ASCE load standard 

(referenced in the model building codes) and its predecessors used a fastest-mile wind speed at 33 

feet (10 meters) over flat, open terrain. In ASCE 7-95, the standard switched from the fastest-mile 

wind speed with its variable averaging time to a 3-second peak gust. Additionally, ASCE 7 editions 

prior to 2010 used a service level wind speed, but also included an importance factor and a load 

factor, which together had the effect of adjusting the return period of the design wind speed from 

a service level to a strength level. In ASCE 7-10 and subsequent editions, the standard has moved 

to a strength-level design wind speed (a simplification that eliminated the importance factor and 

reduced the load factor on wind from 1.6 to 1.0). In addition to other advantages, this change made 

it easier to compare design wind speeds given in the standard (referred to by ASCE 7 as Basic Wind 

Speeds) with observed or forecast hurricane wind speeds3 . 

3A detailed description of the relationship between wind speeds as defined by ASCE 7 and those in the Saffir 

Simpson hurricane wind scale used by the National Hurricane Center is provided in section C26.5.1 of the ASCE 

7-16 Commentary (ASCE 2017).
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Design wind speeds for buildings and other structures in the ASCE 7 standard are also a function 

of the assigned Risk Category, “based on the risk to human life, health, and welfare associated with 

damage or failure by nature of their occupancy or use” (ASCE 2017). Risk Categories range from I 

to IV, where Risk Category I buildings and structures represent low risk to human life in the event 

of failure. Risk Category III represents buildings and other structures that could pose a substantial 

risk to human life, and Risk Category IV includes buildings designated as critical facilities, such as 

hospitals and emergency operations centers. Risk Category II buildings are those not meeting the 

definition of the other three categories, which include most residential and commercial facilities. 

Prior to the ASCE 7-16 edition, there was no differentiation between Risk Category III and IV for 

determination of wind speeds.

The code currently in force in Puerto Rico at the time of preparation of this report references 

ASCE 7-05, which designates a basic wind speed of 145 mph (233 kph) island-wide. Wind speeds 

for different Risk Categories are accounted for indirectly through the importance factor. In later 

editions of ASCE 7, contoured wind speed maps are used, showing the variation of design wind 

speeds with location. The design wind speeds for Puerto Rico in ASCE 7-05, 7-10, and 7-16 are 

compared in Table 2-2 for the four Risk Categories. In ASCE 7-05, the basic (service-level) wind 

speed of 145 mph for the entire Commonwealth is shown in the second column. The third column 

provides equivalent strength-level wind speeds for ASCE 7-05, which can be directly compared with 

the wind speeds in ASCE 7-10 and 7-16. The strength-level wind speeds in Puerto Rico (and on 

the U.S. mainland) decreased in ASCE 7-10 compared to ASCE 7-05, resulting from advances in 

hurricane modeling4.

Table 2-2: Design Wind Speeds for Puerto Rico, in mph (kph)

Risk 

Category

ASCE 7-05 

Basic Wind 

Speed 

(Service Level)

ASCE 7-05

 Equivalent Wind 

Speed 

(Strength Level)*

ASCE 7-10 

Basic Wind 

Speed 

(Strength Level)

ASCE 7-16 

Basic Wind 

Speed 

(Strength Level)

I 145 (233) 161 (259) 140-160 (225-257) 140-160 (225-227)

II 145 (233) 183 (295) 150-170 (241-273) 150-170 (241-273)

III 145 (233) 197 (317) 160-180 (257-290) 160-180 (257-290)

IV 145 (233) 197 (317) 160-180 (257-290) 160-190 (257-306)

* Equivalent strength level wind speed = basic wind speed × square root (importance factor × load factor)

Speeds given represent 3-second-gust wind speeds at 33 feet (10.0 meters) above ground level for Exposure Category C (flat, open terrain), 

as described in ASCE 7.

Sources: ASCE 7-05 (ASCE 2005), ASCE 7-10 (ASCE 2010), ASCE 7-16 (ASCE 2017)

4References documenting the hurricane model improvements are provided in Commentary section C26.5.1 of 

ASCE 7-10 (ASCE 2010).
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BUILDING CODES, STANDARDS, AND REGULATIONS

Increasing wind speeds correspond to increasingly rare events; for example, all wind speeds for 

Risk Category II have an approximate mean recurrence interval of 700 years, equivalent to a seven 

percent probability of exceedance in any 50-year period. In contrast, speeds for Risk Category in 

ASCE 7-16 represent a mean recurrence interval of 3,000 years, equivalent to 1.6 percent probability 

of exceedance in a 50-year period (Table 2-3).

Table 2-3: Probability of Design Wind Speed Exceedance at Least Once in 50 

years.

Risk Category

ASCE 7-10 and Prior 

Editions ASCE 7-16

I 15% 15%

II 7% 7%

III 3% 3%

IV 3% 1.6%

Lastly, it should be noted that wind speeds are but one factor of many in determination of wind 

loads. For example, although the design wind speeds in ASCE 7-16 are slightly lower than the 

equivalent speeds in ASCE 7-05 for Puerto Rico, net uplift loads for the design of components and 

cladding on building roofs will often be greater under ASCE 7-16 than ASCE 7-05. This is due 

to a significant increase in roof pressure coefficients in ASCE 7-16 that resulted from extensive 

wind tunnel testing and was validated through wind load data collected from real buildings under 

straight-line and hurricane wind conditions. Many other changes to the ASCE 7 wind loading 

provisions have occurred between the 2005 and 2016 editions, based on improved understanding of 

the wind hazard and wind-structure interaction. Significant changes are typically described in the 

commentary to each edition of ASCE 7.

2.5 National Flood Insurance Program

Puerto Rico has participated in the National Flood Insurance Program (NFIP) since 1978. 

Development is governed by Puerto Rico’s floodplain management ordinance, Planning Regulation 

13. Building permits within the floodplain are the responsibility of OGPe. Puerto Rico has five NFIP 

communities that may adopt and enforce floodplain management regulations. These five NFIP 

communities encompass all 78 of the municipalities of Puerto Rico. The largest community is the 

Commonwealth of Puerto Rico, which includes 74 municipalities. The additional NFIP communities 

are the municipalities of Bayamón, Carolina, Guaynabo, and Ponce.

Only one community in Puerto Rico, Ponce, participates in the Community Rating System (CRS). 

CRS is an incentive program that encourages communities to develop more hazard-resistant 

building practices. Ponce is a Class 9 community under the CRS rating system, entitling residents in 

SFHAs to a 5 percent discount on their flood insurance premiums. The MAT observed interest in 

the CRS from municipal officials who wished to lower the cost of flood insurance.

The current effective Flood Insurance Rate Maps (FIRMs) for all municipalities in Puerto Rico 

are dated November 2009. Following Hurricanes Irma and Maria, these maps were reviewed to 

determine if the 1-percent-annual-chance flood event (the base flood or 100-year flood) shown on the 
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maps is accurate. Where appropriate, Advisory 

Base Flood Elevations (ABFEs), Advisory Flood 

Zones, and other Advisory Data were developed 

to update the flood hazard maps. On April 13, 

2018 Puerto Rico adopted on an emergency 

basis the ABFEs developed in the aftermath of 

Irma and Maria. The ABFEs were permanently 

adopted for new construction and substantially 

improved or substantially damaged buildings 

on July 11, 2018. The effective 2009 FIRMs shall 

be used to determine NFIP policy premiums 

until the ABFEs is formally adopted as the 

effective FIRMs.

The percentage of NFIP-insured households in 

Puerto Rico is very low compared to the United 

States as a whole. As of the end of 2017, there 

were approximately 44,200 flood insurance 

policies in effect in the Commonwealth. Of 

these, only 4,200 were NFIP policies, the 

remainder being private insurer policies 

(Kousky and Lingle 2018). In contrast, as 

recently as 2009, roughly 60,000 NFIP policies 

were in effect. The sharp decline in NFIP 

policies can be attributed to a few potential causes. From 2011 to 2012, private companies began 

offering flood coverage in Puerto Rico. These policies could potentially offer improved value 

compared to NFIP policies by bundling flood coverage with other coverage, such as vandalism. 

Additionally, only homes with a mortgage, and that are located within the 100-year floodplain, are 

required to carry flood insurance. As the Puerto Rican economy has weakened, many households 

voluntarily carrying coverage may have opted to drop their flood policies for financial reasons. Of 

total occupied housing units, approximately 58 percent are in mapped floodplains, underscoring 

the importance of flood insurance participation in Puerto Rico (Government of Puerto Rico 2017).

PRIVATE FLOOD INSURANCE IN PUERTO RICO

A recent study by the Risk Center at the Wharton 

School of the University of Pennsylvania (Kousky 

and Lingle 2018) highlighted the unique nature of 

private flood insurance in Puerto Rico. 

Overall, fewer than 5 percent of the homes in 

Puerto Rico have NFIP or private flood insurance. 

Approximately 90 percent of the flood insurance 

policies in Puerto Rico are private, compared to 

only 2 percent nationwide.

Private insurance tends to be less expensive 

than NFIP insurance in Puerto Rico. Different 

construction practices are one reason the private 

sector can offer less expensive flood policies.

The availability of private flood insurance in 

Puerto Rico has not led to greater demand. 

One contributing factor could be affordability 

challenges for roughly half of residents currently 

estimated to be living in poverty.

2.6 Standards for Solar Equipment

In Puerto Rico, the permitting of PV panels is managed by OGPe rather than the municipalities. 

Approval by the Puerto Rico Electric Power Authority (Autoridad de Energía Eléctrica), commonly 

known by its English acronym, PREPA, is also required for the system to be connected to the electric 

grid. Permitting of solar power and heating systems is covered under general building requirements, 

which call for a permit certified by a design professional for projects over $6,000. However, PV 

systems typically go through the permitting process regardless of cost according to municipal 

officials, because PREPA requires a permit showing the installation is code-compliant. Conversely, 

installation of a solar water heater on existing buildings typically falls under the $6,000 threshold 

for a certified permit and does not need PREPA review; therefore, solar water heater installations 

are typically unpermitted according to municipal officials. 
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BUILDING CODES, STANDARDS, AND REGULATIONS

The only specific design guidance for solar equipment wind speeds or pressures given in the 2011 

PRBC and its reference standards, including ASCE 7-05, is an amendment added to the IBC© that 

includes design pressures for components and cladding where solar water heaters and PV panels 

are mentioned. Other references appear in the PRBC for installation processes; however, these 

references are broad and primarily focus on the condition of the installation components. Another 

amendment included in the 2011 PRBC includes a requirement that all new houses and townhouses 

use only solar water heaters. Specific design guidelines are not provided. This lack of guidance 

is especially noteworthy given that local permitting does not review or inspect PV panels or solar 

heating system installations. Chapter 6 details the performance of ground-mounted PV systems and 

residential and non-residential rooftop solar equipment.

OGPe has begun a process of adopting the 2018 I- Codes (OGPe 2018), which reference ASCE 

7-16. The biggest improvement from ASCE 7-05 to ASCE 7-16, regarding solar equipment, is the 

addition of design wind loads for rooftop PV panels. Although ground-mount solar equipment has 

not been included in ASCE design standards yet, the addition of rooftop solar equipment design 

guidance will aid in a more complete design standard. With the growing use of solar water heaters 

and PV systems, the importance of appropriate design standards continues to increase, especially 

for locations exposed to extreme wind conditions. 

2.7 Safe Rooms and Storm Shelters 

Safe rooms and storm shelters are purpose-built structures that provide life-safety protection for 

people during hurricanes and tornadoes. Safe rooms provide near-absolute life-safety protection 

for their occupants against both wind 

pressures and wind-borne debris 

impacts associated with tornadoes and 

hurricanes. Design and construction 

criteria for storm shelters are detailed 

in the ICC© Standard for the Design 

and Construction of Storm Shelters (ICC 

500© 2008), which has been adopted 

by reference by the IBC since 2009. 

(The 2009 IBC© is incorporated by 

reference into the 2011 PRBC5.) Design 

and construction criteria for safe rooms 

are found in Safe Rooms for Tornadoes 

and Hurricanes: Guidance for Community 

and Residential Safe Rooms, 3rd Edition 

(FEMA 2015a). 

ICC 500© and FEMA P-361 provide 

the design and construction criteria 

for storm shelters and safe rooms, 

SAFE ROOMS AND STORM SHELTERS

FEMA defines “safe rooms” as buildings or portions 

thereof that comply with the criteria described in 

FEMA P-361, Safe Rooms for Tornadoes and Hurricanes: 

Guidance for Community and Residential Safe Rooms, 3rd 

Edition (FEMA 2015a) for providing near-absolute lifesafety protection from extreme wind events. The ICC© 

defines “storm shelters” as buildings or portions thereof 

that comply with the ICC and National Storm Shelter 

Association (NSSA) ICC/NSSA Standard for the Design and 

Construction of Storm Shelters (ICC 500©, 2014). All safe 

room criteria in FEMA P-361 meet or exceed the storm 

shelter requirements of ICC 500©.

The MAT was not made aware of and did not observe any 

storm shelters or safe rooms in Puerto Rico that met the 

ICC© or FEMA standard.

5The most recent version of ICC 500© is ICC 500-14©.
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respectively. However, neither document requires the construction of purpose-built structures for 

life-safety protection from wind events. Currently, the IBC has a requirement for some new buildings 

to include an ICC 500© storm shelter in tornado-prone regions of the country where the tornado 

hazard design wind speed is 250 mph (3-second gust) or greater. This information is presented in 

IBC 2018 423.3 and 423.4 for specific building uses identified within Risk Category IV and selected 

buildings under the Category E occupancy designation. Several states and local jurisdictions also 

have requirements for the design and construction of storm shelters in tornado-prone regions of 

the country. Florida is the only hurricane-prone state that has a shelter program with triggers that 

require some new facilities to include hurricane storm shelters (through the Enhanced Hurricane 

Protection Area provisions of the Florida Building Code).

While the 2011 PRBC does not mandate the construction of storm shelters or safe rooms, Puerto 

Rico has approved an amendment to the proposed 2018 PRBC that would require schools and 

critical facilities meeting certain criteria to provide storm shelters. The amendments modify IBC© 

2018 Sections 423.3 and 423.4 as follows:

423.3 Critical Emergency Operations. In areas where the shelter design wind speed for hurricanes 

is 190 mph or greater on island states or territories where vehicle access to the continental US by 

roadway is not available, 911 call stations, emergency operations center and fire, rescue, ambulance 

and police stations shall comply with Table 1604.5 as a Risk Category IV structure and shall be 

provided with a storm shelter constructed in accordance with ICC 500©. 

423.4 Group E Occupancies. In accordance with Figure 304.2 (2) of ICC 500©, all Group E 

occupancies with occupant load of 50 or more shall have a storm shelter constructed in accordance 

with ICC 500©.

2.7.1 Design Criteria for Safe Rooms and Storm Shelters 

Safe rooms are planned with one primary purpose: protecting the occupants from hurricanes and 

tornadoes. However, designers and decision-makers must plan for multiple hazards: FEMA P-361 

and ICC 500© criteria address wind as well as other hazards associated with hurricanes, such as 

storm surge, flooding, siting issues, collapse hazards, laydown hazards, and fire. 

Storm shelters are buildings or portions thereof that comply with the ICC 500© standard. All safe 

room criteria in FEMA P-361 meet the ICC 500© storm shelter standard, but FEMA P-361 includes 

recommended guidance that is more conservative than that in ICC 500©. These differences are 

outlined in a table at the beginning of each chapter in Part B of FEMA P-361, and summarized 

in Appendix D. For safe room projects built using FEMA HMA grants, the recommendations in 

Appendix D of FEMA P-361 become requirements. 

The level of protection provided by a safe room or storm shelter is a function of design wind speed 

(and resulting wind pressures) and wind-borne debris impact criteria. The FEMA safe room criteria 

and ICC 500© storm shelter standards are similar, with a few differences, such as siting with respect 

to flood hazards and using FEMA’s recommended guidance to use the 250 mph (402 kph) design 

wind speed for all residential safe rooms (regardless of their location). FEMA P-361 references ICC 

500 for much of the design and construction criteria of a safe room; it also has additional guidance 

on conducting risk assessments, benefit-cost analyses for constructing safe rooms, and guidance on 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 2-15

BUILDING CODES, STANDARDS, AND REGULATIONS

the operations and maintenance of safe 

rooms. 

Traditional buildings are designed to 

withstand a design wind speed, which 

determines the wind pressures the 

structure is designed to withstand. 

In Puerto Rico, the 2018 IBC© is in a 

process of being adopted by OGPe in 

response to the recent hurricanes. ASCE 

7-16 provides wind speed maps used 

for the design of buildings and other 

structures. This standard is referenced 

by the 2018 IBC©. It defines the design 

wind speeds for Puerto Rico in a range 

from 140 to 190 mph (225 to 306 kph), 

depending upon the building use and 

risk categorization.

Design wind speeds for storm shelters 

in hurricane-prone regions in ICC 

500© (referenced by the 2018 IBC©) 

are 190–235 mph (306–378 kph) along 

the Atlantic Coast and 200–250 mph 

(322–402 kph) for the Gulf Coast. ICC 

500©-2014 gives design wind speeds of 

200 mph (322 kph) for hurricanes and 

tornadoes in Puerto Rico. Structures designed to these higher wind pressures provide much greater 

resistance to wind loads than typical buildings and are less likely to be damaged or collapse from 

wind forces experienced during hurricanes.

Besides having a higher design wind speed, a safe room or storm shelter must also be resistant 

to wind-borne debris and falling debris from laydown and collapse hazards. Flood, landslide, and 

seismic hazards must also be considered when siting, designing, and constructing safe rooms and 

storm shelters. Consequently, the structural systems and envelope (building exterior) of a safe room 

or storm shelter, as well as the connections between the building elements, are very robust.

2.7.2 Operations and Planning for Safe Rooms and Storm Shelters

When developing plans for hurricane community safe rooms, designers and other stakeholders 

should consider hazard-specific constraints that may be governed by local emergency management 

or law enforcement requirements, mandatory evacuations, and other emergency plans that affect the 

movement of at-risk populations. For some communities, given sufficient warning of an impending 

hurricane, a large proportion of the population could be expected to evacuate and seek shelter 

outside the at-risk area. Only first responders and a small number of residents would not evacuate. 

In Puerto Rico, in contrast, it is not practical for residents to evacuate the islands, although it may be 

possible to travel within the main island when smaller storms threaten. The difficulty of evacuation 

RESIDENTIAL SAFE ROOMS

A residential safe room is defined in FEMA P-320 Taking 

Shelter from the Storm: Building a Safe Room for Your 

Home or Small Business (FEMA 2014) as a safe room 

serving occupants of a dwelling unit and having an 

occupant load of no more than 16. FEMA P-320 provides 

prescriptive safe room plans that comply with the criteria 

of FEMA P-361 and ICC 500©. These plans are intended 

for residential safe room use but can be used for small 

community safe rooms if the community safe room 

requirements are also met.

ICC 500© DESIGN WIND SPEEDS 

ICC 500-14© provides design wind speeds for tornado 

and hurricane shelters in Figures 304.2(1) and 304.2(2), 

respectively. The minimum design wind speed for 

hurricane and tornado shelters in Puerto Rico is 200 mph 

(322 kph) per ICC 500©. 
2-16 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

BUILDING CODES, STANDARDS, AND REGULATIONS

emphasizes the importance of having purpose-built safe rooms and storm shelters to provide lifesafety protection for residents of Puerto Rico during hurricanes.

FEMA SAFE ROOM GUIDANCE AND INFORMATION

For information on FEMA safe room guidance and programs, see the FEMA Safe Room Resources web page:

https://www.fema.gov/safe-room-resources

Specifically, the following information may be of most assistance to municipalities and entities considering 

a safe room:

• FEMA P-388, Safe Room Resources CD (FEMA 2015)

https://www.fema.gov/media-library/assets/documents/23315

• ICC 500©, ICC©/NSSA Standard for the Design and Construction of Storm Shelters (ICC© 2014)

https://codes.iccsafe.org/public/document/toc/565/

• FEMA P-361, Safe Rooms for Tornadoes and Hurricanes: Guidance for Community and Residential Safe 

Rooms, 3rd Edition (FEMA 2015)

https://www.fema.gov/media-library/assets/documents/3140

• FEMA P-320, Taking Shelter from the Storm: Building a Safe Room for Your Home or Small Business (FEMA 

2014)

https://www.fema.gov/media-library/assets/documents/2009

• FEMA P-341, Tornado Protection: Selecting Refuge Areas in Buildings, 2nd Edition (FEMA 2009)

https://www.fema.gov/media-library/assets/documents/2246
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-1

HURRICANES

IRMA AND MARIA

IN PUERTO RICO

MITIGATION ASSESSMENT TEAM REPORT

Performance of 

Low-Rise Buildings

This chapter describes MAT observations of residential and other 

low-rise buildings, defined as those up to four stories high. 

A description of general types and vulnerabilities of residential and low-rise buildings in Puerto 

Rico is followed by consideration of specific hazards. Finally, the performance of residential and 

low-rise buildings is considered with respect to previous mitigation programs.

In Puerto Rico, the most devastating impacts of Hurricane Irma and especially Hurricane Maria 

can be seen in the damage to residential and low-rise construction, because these are the most 

common type of building. According to a letter dated October 29, 2017, from Governor of Puerto 

Rico Ricardo Rosselló Nevares to Federal Coordinating Officer Michael Byrne, over 300,000 

homes are estimated to have been destroyed and many more damaged across the Commonwealth 

(Rosselló Nevares 2017). Other estimates have included 166,000 residential buildings damaged 

or destroyed (Puerto Rico Central Office for Recovery, Reconstruction, and Resiliency 2018) and 

472,000 housing units having received major damage or having been destroyed. By November 2017, 

there had been more than a million applications for FEMA Individual Assistance. (Government of 

Puerto Rico 2017). Of the homes damaged in Hurricanes Irma and Maria, an estimated 85,000-

90,000 were informally constructed (PRPB Audit and Compliance Bureau 2017).
3-2 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Most housing in Puerto Rico is 40–50 years old. As noted in Chapter 2, only 1 percent of housing 

stock was built after 2010, compared to a national average of 4.2 percent. (Resilient Puerto Rico 

Advisory Commission 2018). 

3.1 Summary of Building Performance 

Unlike most parts of the United States, in which the vast majority of residential units are of woodframed construction, Puerto Rico has a broad range of low-rise and residential construction types 

ranging from one-story, single-family wood-framed buildings with wood-framed metal roofs to twoto four-story, multi-family reinforced cast-in-place concrete-framed buildings with concrete roof 

decks.

The choice of residential construction materials is often driven by economic considerations and 

market availability. Residents with greater financial means tend to choose concrete buildings in 

developed neighborhoods that have been designed and built by professionals following the building 

code. Concrete buildings are more expensive to construct than wood; however, concrete buildings 

are often more flood- and wind-resistant, easier to permit, and less expensive to insure against fire 

and other hazards than wood buildings. Unfortunately, Puerto Rico’s ongoing economic difficulties 

have left 40-50 percent of the Commonwealth’s residents living in poverty (Kousky and Lingle 2018), 

and many residents live in wood-framed buildings.

In addition to the choice of materials, the level of design found in residential construction is also 

often driven by economic considerations. Residents with greater financial means tend to choose 

code-compliant buildings over those built informally. Code-compliant residences are more 

expensive to design and construct; they must be designed by a professional engineer or registered 

architect to comply with current building codes and standards, and construction permits must be 

acquired to ensure buildings comply with Commonwealth requirements. An advantage of codecompliant construction is that code-compliant residences are engineered and constructed to resist 

design flood, wind, earthquake, and other hazards. Because they are permitted and more likely to 

be properly connected to utilities, they are ultimately easier for homeowners to sell and insure.

Concrete buildings typically withstood the combined impacts of flood, wind, and wind-driven 

rain better than wood-framed buildings. The house shown in Figure 3-1 is an example of a type 

of construction that performed well in the hurricanes: Set on an open foundation, it is elevated on 

concrete columns and constructed of concrete, including its roof.

The majority of residential and low-rise buildings observed by the MAT that were destroyed by the 

storms were wood-framed buildings that collapsed from high-velocity flood forces or high wind 

pressures. The MAT observed that these buildings typically lacked a continuous load path to support 

all loads (lateral and vertical). Many wood-framed roofs were also damaged due to inadequate 

roof covering or attachment. Wood-framed buildings and buildings with wood-framed roofs that 

were observed to have proper load paths performed well in high winds. Concrete buildings with 

concrete roofs were generally observed to perform well in high winds; however, the MAT was unable 

to determine the load path connection details. Observations of proper load paths were used to 

distinguish informal from code-compliant construction. This was typically possible for wood-framed 

buildings but not possible with only visual observations for most concrete and concrete masonry 

unit (CMU) buildings.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-3

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-1: Elevated 

concrete house in Punta 

Santiago that performed 

well.

Most residential and low-rise buildings that were damaged, but not destroyed, were inundated by 

low-velocity flooding or experienced water intrusion through damaged roofs. Concrete buildings 

that were inundated or subjected to water intrusion performed better than wood-framed buildings. 

When buildings were inundated by water, the building performance was highly dependent upon the 

ability to rapidly dry the home. Where homes were flooded, they could be cleaned and reoccupied 

as many did not experience structural damage. Observations in this chapter are not intended to 

reject or endorse specific construction materials for residential and low-rise buildings in Puerto 

Rico, but rather to identify and highlight where construction methods (use of load path) or use 

of some materials with specific qualities (such as flood resistance) performed well in a variety of 

conditions.

Table 3-1 provides a summary of the major types of residential and low-rise building construction 

found in Puerto Rico. The table includes sample photos, typical features, and vulnerabilities 

observed by the MAT. Recommended improvements associated with each construction type are 

covered later in the report. In addition to the major types of residential and low-rise buildings listed 

in Table 3-1, Puerto Rico also has some historic buildings and other construction types. Historic 

buildings were typically located in historic urban centers or districts and constructed of wood or a 

combination of wood and concrete with good quality design and construction. Historic buildings 

have typically resisted multiple hurricanes for over 100 years, and most withstood Hurricanes 

Irma and Maria with little or no damage. Other construction types in Puerto Rico include some 

pre-engineered metal buildings and a small amount of manufactured housing. Several older preengineered buildings observed by the MAT were damaged or destroyed by high winds caused by 

key connections that failed due to improper construction detailing or corrosion. The MAT did not 

assess any manufactured housing.
3-4 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Construction 

Type

Typical Features Vulnerabilities Observed

Wood-Framed 

on Piers and 

Posts

● Structural system 

consisting of lumber wall, 

roof, and floor framing

● Elevated foundation on 

timber or concrete piers 

and posts

● Wood panel exterior wall 

covering and galvanized 

metal (zinc) panel roof 

covering

● Predominantly poor-quality construction subject to 

heavy damage due to poor-quality framing connections, 

materials, and structural systems

● Typical 28-guage metal roof covering has virtually no 

diaphragm strength (red circle) with high failure rates of 

gable style roofs

Wood-Framed 

on Slab on 

Grade

● Structural system 

consisting of lumber wall 

and roof framing. Slab-ongrade foundation.

● Wood panel exterior wall 

covering and galvanized 

metal (zinc) panel roof 

covering

● Subject to roof damage or loss due to poor quality 

construction and lack of proper connections to the roof 

and walls

● Slab foundations undermined due to storm surge

Table 3-1: Summary of Major Types of Residential and Low-Rise Construction in Puerto Rico
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-5

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Construction 

Type

Typical Features Vulnerabilities Observed

Concrete with 

Wood Roof

● Concrete block walls and 

wood framed roof with 

plywood deck

● Slab-on-grade or elevated 

concrete pier and beam, or 

pile foundations

● Stucco exterior wall 

covering, galvanized metal 

(zinc) panel or synthetic 

roof covering

● Roof deck and covering subject to wind damage to roof due 

to lack of proper anchor connectors

● Newer structures with hipped roofs sustained less damage 

than observed with gable roofs

All Concrete

● Concrete walls; concrete 

roof deck

● Slab-on-grade or elevated 

concrete pier and beam 

and pile foundations

● Stucco exterior wall 

covering with synthetic 

roof covering

● Many concrete houses in rural areas are informal 

construction and may lack seismic capacity

● Damage can occur when concrete walls are not reinforced, 

or openings are breached, or when subject to coastal storm 

surges forces

● Damage to awnings, clay tile roof accents (red oval) and 

jalousie windows observed
3-6 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Construction 

Type

Typical Features Vulnerabilities Observed

Wood-Framed 

over Concrete

● First-floor concrete wall 

structure with concrete 

roof deck

● Second floor wood-framed 

walls and wood roof built 

on top of concrete ground 

floor

● Stucco exterior wall 

covering and synthetic 

roof covering on concrete 

structures; wood panel 

siding and galvanized 

metal roof panels on wood 

framed structure

● Wood-framed second stories atop concrete ground floor 

structures are typically informal construction built without 

analyzing the additional structural loads imposed on the 

first-floor house

● This typically results in an elevated light wood roof 

structure that cannot resist hurricane winds

● Loss of the wood-framed second floor can lead to water 

infiltration through first-floor roof and create windborne debris damage to the ground floor and surrounding 

buildings

Concrete 

or WoodFramed, 

Supported by 

Columns

● Concrete or wood-framed 

structure over column/pier 

foundation

● Foundations and column/

pier materials vary 

between wood and 

concrete (often matching 

frame construction 

materials)

● Sizes and lengths of 

columns/piers depend on 

site topography

● Observed many foundation failures due to column 

slenderness and poor-quality materials without adequate 

lateral reinforcement

● Columns are in danger of failure during flood/erosion/

earthquake events, leading to structural collapse
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-7

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Construction 

Type

Typical Features Vulnerabilities Observed

Low-Rise 

Construction

● Concrete or wood-framed 

structures with high-end 

wall and roof covering 

materials, like stucco and 

clay tile roofing

● Foundations types include 

slab-on-grade and pier

● Designed and constructed 

in accordance with building 

codes and permitting 

process

● Severe damage to glass windows, glass sliding doors, 

interior gypsum board walls and the exterior wall finishes

● Wind damage to clay roof tile coverings (red circle) and 

rooftop waterproofing systems allowed for rainwater 

intrusion

● Buildings built in coastal zones subject to erosion, storm 

surge, and corrosion damage
3-8 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

3.2 Performance Relative to Flood

MAT observations related to residential and low-rise building performance relative to flooding may 

be grouped broadly by whether they occurred along the coast or in inland areas with heavy rainfall. 

Along the coast, impacts on buildings were primarily caused by forces from coastal flood hazards 

such as inundation, waves, and coastal erosion. Inland flood and rainfall impacts on buildings were 

primarily related to the building type and elements or systems exposed to flooding and rainfall.

FEMA FLOOD RISK TERMINOLOGY

Flood Insurance Rate Maps (FIRMs) delineate flood hazard areas using zone designations that reflect the conditions expected during the base flood. Some flood hazard terms are defined below:

Base Flood. The flood with a 1-percent-annual-chance of occurrence. It is sometimes referred to as the 100-

year flood. (Likewise, the 0.2-percent-annual-chance flood is sometimes called the 500-year flood.) 

Base Flood Elevation (BFE). The elevation of the base flood, usually rounded to the nearest foot. The “E” in a 

zone designation such as “AE” means that a BFE has been established for this zone.

Special Flood Hazard Area (SFHA). The area subject to inundation from the 1-percent-annual-chance flood. 

The SFHA also encompasses areas that are prone to more frequent flooding, for example, flooding from the 

2-percent- or 10-percent-annual-chance event. Subsurface building areas such as basements are subject to 

flooding at a water surface elevation less than the BFE.

VE Zone. 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 or higher) from storms or seismic 

sources. The VE Zone is sometimes called the Coastal High Hazard Area.

AE Zone. The portion of the SFHA not mapped as a VE Zone. Although FIRMs depict AE Zones in both riverine 

and coastal floodplains (as Zones A, AE, and AO), the flood hazards and flood forces acting on buildings in those 

different floodplains can be quite different. In coastal areas, the AE Zone is subject to wave heights less than 3 

feet and wave run-up depths less than 3 feet.

Coastal A Zone (CAZ). Shown on newer FIRMs and the Puerto Rico Advisory Data, CAZs are referenced in ASCE 

24-14 and ASCE 7-16. These are portions of an AE Zone where breaking wave heights are 1.5–3 feet during base 

flood conditions. Flood forces are not as severe as in VE Zones but are still capable of damaging or destroying 

buildings on shallow foundations. 

Limit of Moderate Wave Action (LiMWA). The inland limit of the CAZ, shown as a line on newer FIRMs. For 

more information about the CAZ and LiMWA, see the LIMWA and Higher Construction Standards Fact Sheet 

(FEMA 2018c), https://www.fema.gov/media-library/assets/documents/96413

B, X, and C Zones. These zones identify areas outside of the SFHA. The B Zone and shaded X Zone identify areas 

subject to inundation by the 0.2-percent-annual-chance flood (the 500-year flood). The C Zone and unshaded 

X Zone identify areas of areas unknown flood risk that are above the level of the 0.2-percent-annual-chance 

flood. The NFIP has no minimum requirements for buildings in these zones.

For a listing of NFIP flood zone designations, refer to 44 CFR 59.1. For more on the flood zones, see Answers to 

Questions about the NFIP (FEMA 2011a), https://www.fema.gov/media-library/assets/documents/272
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-9

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

3.2.1 Coastal Flood Impacts

The MAT observed direct coastal flood impacts to buildings by inundation and waves as well as 

damage from erosion that undermined foundations. 

3.2.1.1 Coastal Flood Forces

The MAT observed many low-lying areas along the coast of Puerto Rico that were subjected 

to inundation by coastal storm surge. These areas saw approximately 2-6 feet (0.6-1.8 meters) of 

flooding depth. The buildings in coastal areas are predominantly concrete, which usually survived 

inundation well. However, structural damage was observed when the storm surge also brought waves 

inland and caused coastal erosion.

The MAT observed that there were few buildings elevated in areas subjected to coastal flooding. In 

northern Mayaguez, one home (Figure 3-2, left) was elevated on piles and did not get inundated, 

while the surrounding homes that were not elevated had approximately 4 inches (10 centimeters) of 

storm surge flooding from Hurricane Maria, damaging belongings and utilities. Because the walls 

of the non-elevated buildings were concrete (Figure 3-2, right), no visible flood damage was done 

to the buildings themselves However, submergence of concrete structures in salt water can expose 

internal rebar to chloride intrusion, causing long-term weakening of the structure.

Figure 3-2: Elevated house (left) and non-elevated house (right) in northern Mayaguez, Zone AE.

Punta Santiago took a direct hit from Hurricane Maria, experiencing high winds, storm surge, and 

large waves. Much of Punta Santiago had been mapped in the high-risk flood hazard area on the 

2009 effective FIRM as well as previous FIRMs. In one area of Punta Santiago, where the storm 

surge from Maria was 7-9 feet (2.1-2.7 meters), a multi-story apartment building (Figure 3-3) had 

been built to the most recent FIRM (2009) by elevating on fill to the BFE and did not flood. In 

contrast, many pre-FIRM buildings built at ground level did flood. 
3-10 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-3: Apartment 

building in Punta Santiago, 

Humacao, elevated on 

fill. Adjacent buildings 

experienced significant 

damage from coastal storm 

surge. Effective FIRM: Zone 

AE. Advisory Data: CAZ.

On the previous FIRM, dated 2005 (Figure 3-4, top), the area containing the apartment building 

was shown in a VE Zone. As a result, many buildings in the area were elevated on piles. On the 2009 

current effective FIRM, the area is an AE Zone (Figure 3-4, bottom); however, the BFE is higher on 

the current effective FIRM than on the 2005 FIRM. Therefore, buildings may now be built on fill, 

but they must be elevated to a higher elevation. Due to the higher BFE on the 2009 FIRM compared 

to the 2005 FIRM, the homes elevated on piles to the 2005 FIRM may not have been elevated high 

enough to avoid damage.

Since the location is in an AE Zone on the current effective FIRM, and the Coastal A was not 

previously identified and adopted for VE Zone building requirements, the apartment building shown 

in Figure 3-3 could be elevated on fill for structural support. Because the building was elevated on 

fill to the effective FIRM BFE, 11.1 feet (3.4 meters), and flooding during Hurricanes Irma and 

Maria did not reach the level of the 1-percent-annual-chance flood event shown on the FIRM, the 

building was not inundated. The building is included in the recently developed CAZ in the Advisory 

Data (Figure 3-5); therefore, structural fill will no longer be allowed due to the potential for erosion 

and damaging waves during the 1-percent-annual-chance event. In this neighborhood, many of the 

first row of homes from the shoreline, which were elevated on piles, did not flood and were not 

damaged. However, some buildings elevated on piles were poorly constructed and may not have 

been elevated high enough when built to the 2005 FIRM or older FIRMs (Figure 3-6). Buildings not 

elevated on piles or fill experienced inundation and may have been impacted by damaging waves.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-11

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-4: Top, 2005 superseded FIRM for an area in Punta Santiago; bottom, a portion of the 2009 effective 

FIRM. The apartment building shown in Figure 3-2 is in the VE Zone on the 2005 FIRM and AE Zone on the 

2009 effective FIRM.
3-12 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-5: A portion of the Advisory Data for an area in Punta Santiago. The apartment building shown in 

Figure 3-3 is shown in the CAZ in the Advisory Data.

Figure 3-6: Poorly constructed elevated buildings in Punta Santiago.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-13

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Before Hurricanes Irma and Maria, Punta Santiago had a wide and heavily vegetated beach that 

was stable without a history of shoreline recession. During Hurricane Maria, the area’s beaches 

experienced significant erosion. The Advisory Data highlights this area as one that is at risk from 

storm-induced erosion, and reconstruction or new construction in this area should consider the 

impact of storm-induced erosion to properties (Figure 3-7). Also, because the Advisory Data now 

includes the CAZ, buildings within the CAZ will have to build to V Zone standards with the adoption 

of the 2018 IBC and IRC in Puerto Rico.

Figure 3-7: Left, storm-induced beach erosion in Punta Santiago. Right, the location (red box) of the 

apartment building shown in Figure 3-3 overlaps a region of Hurricane Maria beach erosion (yellow shading) 

identified in the Advisory Data.

Overall, concrete construction in coastal areas resisted minor coastal forces, and elevated coastal 

concrete buildings withstood wave impacts. Wood construction in coastal areas subject to waves was 

observed to sustain major damage or complete destruction. Areas observed in which flood depths 

and conditions from Hurricane Maria could have supported damaging 1.5-foot (0.5-meter) waves 

were limited to the first several rows of buildings from the coastline. In most of these areas, these 

first rows were not elevated, but many had concrete walls. Most buildings sustained only minor 

damage. Figure 3-8 (left) shows a house in Fajardo built at grade with concrete walls. Based on 

estimated Maria flooding depths and the house’s location along the first row of buildings, it would 

have been subject to wave heights 1.5 feet (0.5 meters) or greater, implying that the house is in a 

CAZ. This house had minor damage from waves. By contrast, Figure 3-8 (right) shows an area in 

Punta Santiago where there is an eroded beach and lower ground elevations. This area was subject 

to larger storm surge and wave heights, and more evidence of wave damage can be seen; wood 

homes built on piles, while not inundated by storm surge, appear to have been impacted by waves 

and wind and were destroyed, however, the concrete buildings built at ground level or on piles and 

impacted by the same wind, depth of flooding, and wave heights performed well (Figure 3-9).
3-14 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-8: Left, concrete house in Fajardo subject to 1.5-foot (0.5-meter) wave heights. Current FIRM and 

Advisory Data: VE Zone. Right, elevated beachfront house in Punta Santiago, Humacao subjected to wave 

heights greater than 1.5 feet (0.5 meters). Current FIRM: AE Zone. Advisory Data: CAZ.

Figure 3-9: Left, an 

elevated wood-framed 

house in Punta Santiago 

was destroyed, right, an 

elevated concrete house 

withstood wind and coastal 

wave forces. Current FIRM: 

VE Zone.

I-CODE REQUIREMENTS FOR COASTAL A ZONES

The current PRBC incorporates the 2009 IBC and 2009 IRC, which reference ASCE 24. Under the IBC, buildings 

in a Coastal A Zone (CAZ) must be designed to V Zone standards; however, CAZ buildings subject to the IRC, including detached one- and two-family dwellings, among others, can be designed to less stringent requirements 

that comply with ASCE 24 while not meeting V Zone standards. The 2018 IBC and IRC, which are expected to be 

adopted by Puerto Rico in 2018, both require all CAZ buildings to be designed to V Zone standards.

To reduce vulnerability to future flood damage and increase disaster resilience, FEMA recommends that all 

structures in a CAZ be designed to V Zone standards regardless of whether this is required by code.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-15

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

There were some elevated buildings in the area that were destroyed, but these were wood-framed 

buildings damaged by the high winds when Hurricane Maria made landfall. Property owners in 

low-lying coastal areas with homes severely damaged by Hurricanes Irma and Maria should consider 

determining whether they are in a CAZ and rebuilding appropriately to help minimize future 

damage.

At Playa Cortada, Santa Isabel, storm surge and waves battered the shoreline. Storm surge in 

this area ranged from 4-6 feet (1.2–1.8 meters), inundating the coastal community and allowing 

damaging waves to impact the buildings along the shoreline. Several homes built at grade along the 

shoreline at Playa Cortada suffered major damage from the storm surge and waves. The building 

shown in Figure 3-10 is a one-story home built at grade that experienced major damage. Based on 

a high-water mark, the storm surge reached a maximum depth of 26 inches (66 centimeters) in 

the interior of the home. The surge and waves also eroded sand and rocks from the shoreline and 

deposited them in and around homes along with rubble from broken-up concrete perimeter walls 

(Figure 3-11). This depth would have allowed at least 1.5-foot waves, the wave height criterion for a 

CAZ, to impact the homes in the area. A water depth of approximately 2 feet is all that is necessary 

to support 1.5-foot waves.

Figure 3-10: Left, house in Playa Cortada subject to damaging storm surge and waves; right, high water mark 

from storm surge 2.2 feet (0.66 meters) above the floor.

The 2009 current effective FIRM for the area, as well as the Advisory Data, identifies at least the 

first row of buildings from the shoreline in the VE Zone (Figure 3-12). Most of the homes in Playa 

Cortada are currently not elevated on piles. At least the first row of homes from the shoreline will 

be required to be rebuilt to VE Zone standards and elevated on piles for new construction or for 

existing homes that are substantially damaged or substantially improved1 .

1NFIP regulations define substantial improvement and substantial damage in Title 44 of the Code of Federal 

Regulations Section 60.3. Briefly, substantial damage is damage for which the total cost of repairs is 50 percent or 

more of the structure’s market value before the disaster occurred, regardless of the cause. Likewise, substantial 

improvement is any reconstruction, rehabilitation, addition, or other improvement of a structure, the cost of 

which equals or exceeds 50 percent of the structure’s market value before the start of construction.
3-16 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-11: Shoreline at 

Playa Cortada where 

sand, rock, and brokenup debris covered the 

ground.

Figure 3-12: A portion of the 2009 current effective FIRM for Playa Cortada.

While Playa Cortada did not experience a large amount of storm erosion to the shoreline, it is an 

area subject to long term erosion and shoreline recession. For rebuilding and new construction 

along the shoreline, planners, developers, designers, owners, among other stakeholders, should 

consider the impacts of long-term erosion as presented in the Advisory Data for 30-year and 60-year 

shoreline positions (Figure 3-13) when siting buildings on properties and constructing homes to 

minimize their risk.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-17

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-13: An example of 

projected future shoreline 

positions after long-term 

coastal erosion, Playa 

Cortada, Santa Isabel.

3.2.1.2 Coastal Erosion

Another major cause of damage to residential and low-rise coastal buildings during Hurricane Irma 

and Maria was erosion that undermined foundations. While many houses may have had a wide 

beach in front of them at one time, many years of erosion have placed them precariously close to the 

water line and they are now at higher risk of damage or destruction by erosion and undermining 

of their foundations from storm surge and waves. The MAT observed many residential buildings 

that were spared from significant damage during Irma and Maria but lost their ocean-facing 

decks because of the storm-induced erosion. The MAT also observed many protective walls and 

buildings that were damaged or destroyed by Irma and Maria, leaving the loose ground behind 

them susceptible to erosion. Because many of the houses in these areas were not identified as being 

in a coastal flood hazard area on the existing FIRMs, they were not required to be built to withstand 

coastal erosion impacts with deep/pile foundations. Owners of new construction or buildings being 

rebuilt in highly erosive areas should consider relocating from the coastline toward the inland edge 

of their property line where feasible and constructing to V Zone standards that account for erosion 

and scour as part of their deep foundation design. Hurricane Maria Advisory products for longterm erosion and storm erosion impacts are available and should be used to help identify areas 

vulnerable to erosion. Table 3-2 provides examples of many of the buildings observed by the MAT 

that were damaged by coastal erosion. 

The home in Rincón shown in Figure 3-14 is located along Corcega Beach. This area has been 

known for chronic storm-induced erosion of its beaches. The building is a multi-level residence 

with a deck facing the water and porches on the side. Hurricanes Irma and Maria caused significant 

erosion in the area. Any pre-existing sandy beach fronting the building was lost, and the ground was 

eroded out from under the deck and building causing failure and collapse of the deck and porches.
3-18 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-14: Multi-story 

residence in Rincón that 

partially collapsed due to 

coastal erosion.

Table 3-2: Examples of Coastal Erosion Damage Observations

Home in Rincón undermined by longterm erosion

Current FIRM VE Zone, BFE 3.4 m

Advisory Data VE Zone, BFE 3.4 m

Protective walls and decks in Rincón 

damaged by erosion

Current FIRM Unshaded Zone X

Advisory Data Shaded Zone X

Home in Rincón undermined by 

long-term erosion

Current FIRM Unshaded Zone X

Advisory Data Shaded Zone X

Homes in Rincón built too close to 

shoreline, subject to severe wave 

action and erosion of pile foundations

Current FIRM VE Zone, BFE 4.6 m

Advisory Data VE Zone, BFE 4.6 m

Homes in Shacks Beach, Isabela 

built on top of sandy coastal dune, 

subject to erosion

Current FIRM Unshaded Zone X

Advisory Data Unshaded Zone X

Homes in Shacks Beach, Isabela 

built on top of sandy coastal dune, 

subject to erosion

Current FIRM Unshaded Zone X

Advisory Data Unshaded Zone X
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-19

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Protective wall failure due to lack 

of tie-back rods to prevent seaward 

slumping of wall due to erosion

Current FIRM Unshaded Zone X

Advisory Data Shaded Zone X

Beach erosion in Luquillo exposing sheet pile (red arrow) protecting 

road.

Current FIRM AE Zone, BFE 2.4 m

Advisory Data AE Zone, BFE 2.4 m 

Parking area behind house in 

Luquillo undermined by erosion

Current FIRM VE Zone, BFE 4 m

Advisory Data VE Zone, BFE 3 m

*Zones AE and VE are in the SFHA. Zone X is outside of the SFHA and represents an area of minimal flood hazard. 

In addition to storm-induced erosion, Rincón has been experiencing long-term erosion and 

shoreline retreat (Thieler, Rodriguez and Himmelstoss 2007). The area also experienced significant 

erosion from hurricane Matthew in 2016 even though the storm tracked far to the south and west 

of Puerto Rico (Aponte-Bermúdez, et al. 2017). Figure 3-15 shows several aerial photographs taken 

over time. In the 1930s, there was a wide natural sandy beach and no development in the area. Since 

the 1930s, the area was developed and homes built. However, without consideration of the longterm erosion impacts, the buildings were built at an elevation and a distance from the water that 

were thought safe. Over time, that beach has eroded, leaving the homes at a greater risk to damage 

from coastal storms. Before the 2017 hurricanes, the beach in front of this building had already 

been eroded away, leaving the building vulnerable to undermining by storm surge and waves.

As part of the Puerto Rico Advisory Data effort, long-term erosion rates were estimated, and 30-year 

and 60-year future shoreline positions were estimated (Figure 3-16). These Advisory products show 

areas, such as in Rincón, which are potentially subject to long-term and storm-induced erosion risks 

to guide smarter siting and design decisions.
3-20 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-15: Aerial photographs of a beach in Rincón showing the residence pictured in Figure 3-14 (red box). 

Left, 1930s aerial showing wide natural beach with no development. Source: López Marrero, et al. (2017). 

Center, pre-Irma and -Maria aerial. Source: ESRI, Digital Globe, GeoEye, Earthstar Geographics, CNES/Airbus 

DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community. Right, post-Irma and -Maria aerial showing 

storm-induced erosion of the narrow beach. Source: NOAA 2017.

Figure 3-16: An example of 

projected future shoreline 

positions after long-term 

coastal erosion, showing 

the residence pictured in 

Figure 3-13 (red box).
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-21

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

The 2005 FIRM for the area did not show the beachfront houses to be in the SFHA. In 2009, a 

new coastal flood risk study was performed, and a new FIRM was released. The 2009 FIRM and 

the Advisory Data show the buildings in the area in the VE Zone (Figure 3-17) partly due to storminduced erosion risk having been considered in the 2009 coastal study. There is no AE Zone mapped 

in this area, as the 100-year floodplain terminates with the limit of the VE Zone. Because this area 

was developed before the 2009 FIRM, the buildings would not have had to comply with VE Zone 

building requirements. Now that the effective FIRM and Advisory Data show the area in a VE Zone, 

any new construction or reconstruction for existing homes that are substantially damaged or are to 

be substantially improved must be built to VE Zone standards. 

Figure 3-17: Outdated 2005 FIRM versus current effective 2009 FIRM with updated coastal analysis that includes 

storm erosion in Rincón around the house shown in Figure 3-14 (red box).

3.2.2 Inland Flood Impacts

Inland flood and rainfall impacts include riverine and sheet flow inundation and impacts from 

intrusion of wind-driven rain.

3.2.2.1 Building Performance

Concrete and concrete-framed buildings observed by the MAT performed better than wood-framed 

buildings under most inland flood and rainfall conditions. This was because most concrete buildings 

in Puerto Rico used either uninsulated concrete or CMU infill walls, both of which are classified 

in NFIP Technical Bulletin 2 Flood Damage-Resistant Materials Requirements (FEMA TB-2 2008) as 

flood-damage-resistant materials. The higher hydrostatic and hydrodynamic load-bearing capacity 

of concrete and concrete-framed buildings, especially reinforced concrete systems, contributed to 

their good performance.
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PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Additionally, most concrete-roofed one- and two-family dwellings used moisture-resistant materials 

to manage water intrusion and damp/wet island conditions. The preferred materials included 

plaster, masonry, tile, and stone finishes that are less likely to absorb moisture and are generally 

considered flood-damage-resistant per FEMA TB-2. Figure 3-18 shows typical flood-damageresistant interior finishes for a concrete residence under construction in Yabucoa.

Figure 3-18: Painted 

concrete, a typical flooddamage-resistant interior 

finish, in a concrete house 

under construction in 

Yabucoa.

One homeowner in Humacao showed the MAT a list with all the items needing replacement after 

his concrete house was inundated; the list included possessions and appliances but no supplies 

for rebuilding or renovating. Although the first floor was flooded, the house was still habitable, 

with only the contents needing to be replaced. The use of flood-damage-resistant materials greatly 

reduced the time and expense of reoccupying this home.

Unlike concrete buildings, most wood-framed buildings used wood panels or other cladding 

materials that are not considered flood-damage-resistant per FEMA TB-2, resulting in greater flood 

damage and cleanup costs associated with floodwater inundation and rainwater intrusion (Figure 

3-19).
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-23

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-19: Wood roof in 

Toa Alta that failed due 

to insufficient design and 

detailing, allowing rain to 

enter the building. It was 

constructed with wood 

panels or other materials 

that were not considered 

flood-damage resistant.

Although concrete roofs performed much better than wood-framed roofs, the MAT observed water 

ponding on some flat concrete roofs of residential and low-rise commercial buildings (Figure 3-20). 

Most of the flat concrete roofs observed by the MAT where ponding as a result of the extreme rainfall 

from Hurricane Maria was observed had inadequate roof drainage with too few and undersized 

roof drains (1.5–2-inch [3.8–5.1-centimeter] diameter instead of 4-inch [10.2-centimeter]) and 

inadequate roof slope toward the drains (less than 1/8-inch per foot [1:96]) or a lack of roof 

maintenance, with drains clogged by debris or vegetation. Other flat concrete roofs experienced 

water ponding due to deformation of the roof slab leading to low spots, which tended to occur more 

in low quality mass-produced housing developments or informal construction.

Figure 3-20: Water ponding on flat concrete roof of a residence in 

San Juan.
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PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-21: Wood framed 

residence in Toa Baja 

neighborhood pushed 

off its foundation by high 

velocity riverine flooding.

Most inland flood and rainfall damage to residential and low-rise buildings observed by the MAT 

were the result of inundation from local drainage or low-velocity riverine flooding or rain intrusion 

from roof damage or wind-driven rain. However, the MAT did observe some inland flood damage 

apparently caused by sheet flow and high-velocity riverine flooding. Figure 3-21 shows a wood-framed 

residence in one neighborhood of Toa Baja pushed off its foundations by high-velocity flooding, and 

Figure 3-22 shows a concrete residence in Utuado that was impacted by sheet flow flooding, with 

minimal structural impact.

Figure 3-22: Concrete house in 

Utuado impacted by sheet flow 

flooding.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-25

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

3.2.2.2 Foundation Performance

The MAT observed very few residences or low-rise buildings with basements, defined by the NFIP 

as any area of a building having its floor subgrade (below ground level) on all sides (FEMA 2014), 

but did observe other foundation types throughout the Commonwealth. In flood-prone areas, the 

MAT observed more houses elevated over columns. However, these buildings often closed the semiopen space underneath the building with CMU walls that were rigidly attached to the columns to 

create more living space, rather than keeping the area free of obstructions or adding hydrostatic 

openings. Unfortunately, this approach not only increases vulnerability to inundation from shallow 

flood events, it also increases the risk of the walls collapsing under hydrostatic and/or hydrodynamic 

forces in larger flood events, which could lead to a failure of the columns and complete structural 

collapse. Figure 3-23 shows a failed CMU wall attached to columns that contributed to a residential 

deck collapse in Isabela. 

Figure 3-23: Failed CMU 

wall (red circle) attached 

to columns at a house 

in Isabela. The failure 

contributed to the collapse 

of a residential deck 

supported by the columns. 

Current FIRM: Unshaded 

Zone X. Advisory Data: 

Unshaded Zone X, Erosionimpacted area.

3.2.2.3 Mechanical, Electrical, and Plumbing System Performance

Protecting mechanical, electrical and plumbing (MEP) system equipment and components in 

residential and low-rise buildings from natural hazards is important for ensuring the speedy recovery 

of homes and small businesses that survived the storms. Not surprisingly, the MAT observed that 

elevated or rooftop building MEP equipment experienced less flood damage than MEP equipment 

placed at grade. This was especially true for residential and low-rise buildings with concrete roofs, 

where MEP equipment is easier to secure against wind and seismic hazards by anchoring into the 

roof deck (Figure 3-24).
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PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-24: Solar water 

heater and cistern on a 

residential concrete roof 

in Rincón.

MEP equipment located on elevated cantilever structures observed by the MAT typically performed 

well (Figure 3-25). However, many concrete houses in Puerto Rico have aleros, overhangs above 

their windows (Figure 3-26), and some homeowners may not understand that the structural 

capacities of the overhangs are not the same as cantilever structures. This can lead to the collapse 

of the overhangs and potential injuries to residents. Therefore, although locating MEP equipment 

over an elevated cantilever structure can be an effective flood mitigation strategy, it is important 

to differentiate cantilever structures from existing overhangs and carefully consider the placement 

and the weight of the equipment.

Figure 3-25: Typical 

overhangs (aleros) above 

the windows of a concrete 

residence.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-27

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-26: Air

conditioning equipment 

elevated on a cantilever at 

a concrete house in Punta 

Santiago, Humacao. This 

means of elevating 

equipment typically 

performed well, as here.

Supporting frames can also be used to elevate MEP equipment when properly designed and 

constructed. However, as with cantilever structures, supporting frames must consider the MEP 

equipment weight and bracing. Figure 3-27 shows a supporting frame for an elevated residential 

cistern that does not appear to have been professionally designed or inspected to ensure it can 

handle the weight of the tank or lateral forces on the tank or the frame. Lacking bracing in the 

vertical plane of the columns, it appears seismically vulnerable.

Figure 3-27: This frame supporting a 

residential cistern did not appear to be 

professionally designed.
3-28 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Many low-rise residential and commercial property owners had water intrusion problems through 

air conditioning (AC) unit drainage lines and windows due to improper installation of rooftop or 

window-mounted AC units. Residential concrete buildings experienced problems related to water 

damage on wood doors, while commercial buildings exhibited damage and mildew on gypsum 

board wall partition and floor materials including tile.

3.3 Performance Relative to Wind 

The MAT observed varied performance of low-rise buildings and one- and two-family dwellings. 

Material selection, the presence of a continuous load path, and protection for openings (windows 

and doors) all played a part in whether a building performed well. While building successes were 

observed in wood-framed, reinforced concrete and reinforced CMU homes, the MAT observed that 

the reinforced concrete and CMU homes with concrete roof decks exhibited the best performance 

resisting wind loads. 

Informal construction observed by the MAT was missing critical connections to hold structural 

members together. As a result, many roof structure and wall failures were observed; these were the 

most catastrophic of the observed failures. When some load paths were present, damage was often 

extensive but did not result in the failures of the main wind force resisting system (MWFRS). The 

most common structural failures were partial failures of the MWFRS and failures of components 

and cladding systems. 

Overall, the most common damage type observed was water intrusion. Window damage was often 

the cause.

MAIN WIND FORCE RESISTING SYSTEM

The MWFRS is “an assemblage of structural elements assigned to provide support and stability for 

the overall building or other structure. The system 

generally receives wind loading from more than 

one surface” (ASCE 7-16, 26.2).

CONTINUOUS LOAD PATH

The structural condition required to resist loads 

acting on a building. The continuous load path 

starts at the point or surface where loads are applied, moves through the building, continues 

through the foundation, and terminates where the 

loads are transferred to the soils that support the 

building (FEMA 2011).

3.3.1 Main Wind Force Resisting System 

The MWFRS is defined in ASCE 7-16 as the “assemblage of structural elements assigned to provide 

support and stability of the overall building” (ASCE 7-16). The MWFRS is a critical portion of a 

continuous load path that carries loads acting on buildings from the building envelope into the 

structural elements of the MWFRS, into the foundation, and finally into the ground. If there is a 

break or missing element in the continuous load path in the building when lateral or uplift loads 

occur from a flood, wind, or seismic event, then a failure in some or all the building’s structural or 

envelope system usually occurs. Figure 3-28 gives an example of how a continuous load path carries 

loads through a home.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-29

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-28: Example 

of a continuous load 

path in a concrete 

building with 

masonry infill.

Low-rise and residential buildings observed by the MAT exhibited varied performance in the winds 

associated with Hurricane Maria. Many of the buildings where roof deck, roof structure, and wall 

failures occurred were lacking the continuous load path at specific connection points. The most 

common failure points in the load path were observed at the following locations:

● Roof deck to roof framing or purlins (typically observed as a metal panel roof covering with no 

plywood or slat board decking present below the metal panels)

● Roof framing connection at the top of the wall (to wood-framed, concrete, or CMU walls)

● Lower wall to upper wall connections

● Overhangs and cantilevered or lightly supported roofs (deck roofs, carports, and other 

awnings)
3-30 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

3.3.1.1 One- and Two-Family Residential Buildings

The MAT observed some wood-framed buildings that were well-constructed and experienced only 

minor damage. In these houses, the load path was established throughout the buildings using a 

combination of metal connectors and bolted or screwed connections between wood members. While 

the house in Figure 3-29 was a success, many wood-framed buildings did not perform well. As noted 

earlier, the primary factor contributing to the poor performance of wood-framed buildings was the 

lack of continuous load paths. When there were not continuous load paths within the MWFRS, the 

building would experience partial or complete failure in the wood roof or wood wall framing. Based 

on field observations, the MAT observed the following key causes of failure:

● The buildings were never designed to resist high wind loads, and a continuous load path with 

engineered connections between structural members was not provided.

● The buildings are older and were constructed prior to the residential design criteria which 

specified requirements for wind resistant construction.

● The buildings were informally constructed.

Figure 3-29: Example of a 

wood-framed home in 

Vieques that performed 

well during Hurricane 

Maria.

Figure 3-30 and Figure 3-31 illustrate failures in the continuous path in one- and two-family houses 

with wood-framed walls and roofs or with wood-framed roofs with concrete wall framing. The 

common use of large metal panels as roof coverings atop lightly constructed wood-framed roof 

systems with no structural deck between the panels and the supporting frame exposed many homes 

to rain and wind, causing significant damage. Figure 3-31 shows the most frequently observed 

failure type in buildings with wood-framed roofs: damage to some or all of the wood-framed roof 

system. For both houses, wind forces removed a portion of the metal panel roof covering. With 

the loss of the roof covering, the roof structure became unstable, because the metal panel was the 

only element of the roof system providing lateral load support. As the roof lost support, some or all 

of the roof system failed, because there was no roof deck below the roof covering. This probably 

contributed to the complete destruction of the wood-framed house in Figure 3-30 and structural 

damage to as well as significant water intrusion into the concrete house with wood-framed roof in 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-31

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-31. Had roof decking been present and a proper load path provided, the building would 

have performed much better, minimizing or eliminating exposure of the interior of the home to 

rain or debris from its own failed elements.

Figure 3-30: Wood-framed 

house in Toa Baja. With 

the loss of the roof and 

wood-framed structural 

walls, the elevated living 

space was completely 

destroyed.

Figure 3-31: Concrete 

house with major damage 

to wood-framed roof 

system.
3-32 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-32 shows an example of an informally constructed wood-framed addition to a home. This 

addition, on the second story of the home was on top of the reinforced concrete roof of the first 

floor of the home. At this home, there was no structural deck below the metal panel roof covering, 

roof rafters were not connected to the top of the wall framing with connectors capable of resisting 

uplift loads, and there was no lateral support for the roof rafters.

Figure 3-32: Informally 

constructed second story 

wood-framed addition in 

Loíza with partial loss of 

metal panel roof covering 

and wood-framed roof 

system.

Additions to existing houses were frequently of wood-framed construction. These additions were 

second stories atop a concrete or CMU home or additions to the side of the home. Most of these 

additions were informally constructed, with little to no engineering design, and these structures 

performed poorly, with loss of roof covering, roof structure (no deck was present) and wall failures. 

Figure 3-33 shows a wood-framed, second story addition that lost its entire wood-framed roof 

structure.

Figure 3-33: Second story 

wood-framed addition 

in Canovanas which lost 

the entire wood-framed 

roof on the second story 

addition.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-33

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Many homes were constructed from reinforced concrete frames or walls, reinforced CMU, and 

reinforced concrete roof decks. These buildings exhibited the best performance and resistance to 

damage from high winds. Figure 3-34 shows two homes in Caguas; the beige home on the left with 

the reinforced concrete roof deck experienced no structural damage, while the light blue CMU 

home on the right lost most of its wood-framed roof and metal panel roof covering. Most of the 

homes with concrete roof decks visited by the MAT were observed to have little or no structural 

damage from the hurricanes (Figure 3-35). This was true for homes on the coast near landfall and 

those inland. Some of these homes experienced minor damage due to failed opening protection or 

roof coverings. The MAT was not able to confirm whether all the reinforced concrete and reinforced 

CMU homes observed during site visits had approved permits and were formally constructed. 

Figure 3-34: Comparison 

of two homes in Caguas: 

Left, the beige house had 

a reinforced concrete roof 

deck and experienced no 

structural damage; right, 

the blue CMU home lost 

most of its wood-framed 

roof and metal panel roof 

covering.

Figure 3-35: Concrete residences in, left, Palmas del Mar; right, Loíza, that performed well with no structural 

damage.

Homes with reinforced concrete roof decks did experience failures and damage during the 

hurricanes. The home in Figure 3-36 lost a portion of its reinforced concrete roof deck. This home 

in Yabucoa, near where Hurricane Maria made landfall, was located on a bluff overlooking the 

ocean. Wind forces coming up the hillside from the water caused a failure in the concrete roof deck 

over the porch. The damage observed at this location appeared to be caused by a lack of adequate 

reinforcing steel in the connection between the roof deck and the supporting beam. As a result, 

the roof deck was peeled back by the wind when the reinforced concrete was not able to resist wind 

loads. 
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PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-36: Failure of 

reinforced concrete roof 

deck over garage. Source: 

Héctor J. Cruzado, PhD, PE 

and Gustavo E. PachecoCrosetti, PhD, PE.

It is common practice in Puerto Rico to build homes with steel reinforcing bars protruding through 

the roof, so that the homeowner may add an upper floor in the future. The MAT observed such 

staged construction practices throughout Puerto Rico (Figure 3-37). However, steel rebar that is left 

unprotected for months or years can corrode and weaken, making it unsuitable for its intended use.

Figure 3-37: This home 

in Vieques had rebar 

exposed on the roof (red 

circles), indicating that 

the homeowner planned 

to add a second story 

sometime in the future.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-35

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

3.3.1.2 Low-Rise, Multi-Family Residential Buildings

In addition to one- and two-family dwellings, the MAT visited low-rise buildings used for multi-family 

residential and light commercial use. These buildings were observed to be of load-bearing-wall 

construction or multi-story framed construction. The buildings were likely all professionally

designed and engineered to resist wind, flood, seismic, and gravity loads. The MAT observed that 

very few of these buildings experienced structural failures of the MWFRS due to wind forces alone. 

In general, these larger buildings had a continuous load path that resisted wind loads without failure. 

Exceptions to this good performance occurred when building materials were in poor condition 

or where the building was impacted by falling or wind-borne debris. Figure 3-38 shows a low-rise 

building on the coast in Palmas del Mar, Humacao that had no damage to its structural systems. 

However, high winds, wind-driven rain, and wind-borne debris caused damage to roof coverings 

and windows, displacing residents from this building complex after the storm.

Figure 3-38: Low-rise 

building on the coast in 

Palmas del Mar that lost 

tile roof coverings.

3.3.2 Windows

Window damage is very common following hurricanes. The MAT observed both glazed (made of 

glass) and non-glazed window systems. Glass casement and glass jalousie windows were the most 

commonly observed glazed window systems, and metal panel jalousies were the most commonly 

observed non-glazed window systems. Performance of window systems varied depending on

material type, quality of installation, condition of the window system, and the framing or structure 

supporting the window opening. Water intrusion occurred due to window systems having poor seals 

or seals that were never designed or intended by the manufacturer to be watertight, or when window 

systems were impacted and damaged by wind-borne debris impact. Water was also observed to have 

blown in under doors, leading to property damage. 
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PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

In addition to keeping wind-driven rain and water out of a building, window systems can affect the 

performance of a building during a hurricane or high wind event. Window systems can be designed 

to resist wind pressures and prevent wind forces from entering a building, and the proper design 

of the building itself must consider whether the window system allows wind to enter the building 

(a partially-enclosed condition) or keeps wind out of the building (an enclosed condition). Older 

buildings and informally constructed buildings were not designed to withstand the increase of wind 

pressures within the buildings due to the use of window systems that allowed wind pressures to 

enter the buildings (the partially-enclosed condition). This contributed to increased pressures on 

roof systems from within the buildings, precipitating the failure of roof decking, roof framing, and 

entire roof systems.

3.3.2.1 Jalousie Windows

The most common window system observed in residential buildings in Puerto Rico is the jalousie 

window system (Spanish: ventanas de celosia). These window systems allow natural ventilation to 

help control the temperature inside the building while also limiting sunlight into the building 

and providing visual privacy. However, they are not air- or watertight and allow air to flow through 

the building. Jalousie window systems contain panels (louvers) made of metal, glass, or wood that 

are typically opened or closed by turning a handle. Figure 3-39 shows an elevated single-family 

residential building with metal jalousie windows. Figure 3-40 shows a close-up view of a metal 

jalousie window. 

Figure 3-39: Elevated 

concrete residential 

building with glass jalousie 

windows.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-37

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-40: Close-up of jalousie windows 

with metal louvers on a residential 

building.

Jalousie window systems are typically used because they are 

an affordable window option with a number of practical 

benefits. However, because they are inherently “open,” nonsealed systems, they allow the passage of wind-driven rain, 

water, and air into buildings, which can lead to damage 

of the interior walls, interior floor, and building contents 

due to wetting. It also can lead to damage or failure of 

the building’s structural systems (most commonly the 

roof systems) because wind pressures allowed within the 

building overload the roof structure; the wind loads within 

the building were probably never considered in the design. 

The common use of metal panel jalousie window systems 

in informally constructed homes contributed to the failure 

of many roof systems in the residential buildings the MAT 

observed.

Although the louvers of jalousie windows are commonly 

made of metal, or occasionally wood, they may also be 

made of glass; however, observations on the performance 

of glazed windows are presented in the next section of this 

report. Traditional glazed window systems, whether they 

are fixed or operable, are typically more air- and watertight than jalousie window systems, which are inherently 

difficult or impossible to seal.

3.3.2.2 Glazed Windows

Glazed windows are a popular window type for buildings with central air conditioning, as they 

allow openings to be sealed, preventing airflow and moisture from entering the building under 

normal conditions. Glazed windows are common although not as popular in Puerto Rico as in most 

other parts of the United States. Glazing in many observed homes did not appear to be adequately 

secured to resist failure from wind pressures, regardless of the age of the home. The PRBC requires 

that glazing in wind-borne-debris regions and hurricane prone regions, which include all of Puerto 

Rico, to be either adequately rated for impact resistance or have hurricane shutters. 

The most common damage observed for glazed windows was damage from wind-borne debris and 

water intrusion at gaps in window sills. Pressure from high winds forced water through poorly sealed 

openings, around window frames, and into the building, even if the glazing was closed and locked. 

Windows that are not adequately attached to a building can become a hazard. Glazing, particularly 

those covering large openings, must be adequately anchored to the building. The structure 

surrounding the opening needs to be adequately designed, or strengthened if necessary, to handle 

the load transferred by the window or its covering.
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In Figure 3-41, a large window was blown into the building, and the glazing broken, which could 

have injured any occupants of the building. There are no signs of anchors having been pulled out of 

the block or causing widespread damage to the edges of the opening, which indicates the fasteners 

that attached the glazing frame to the opening were inadequate.

Figure 3-41: Low-rise 

residential building with 

large glazed windows 

blown in (yellow arrows) 

and windows broken (red 

arrow).

The homes in Figure 3-42 and Figure 3-43 utilized impact-resistant glazed casement windows. 

These windows are very popular in Puerto Rico, as they can be opened wide to allow circulation 

and airflow. The glazed doors and windows on both homes performed well during these storms and 

did not suffer breakage of glazing during either hurricane. Water intrusion and damage from winddriven rain was minimal due to excellent seals around the windows and doors. Figure 3-42 shows 

a close-up view of the double-glazed casement windows and seals. Seals around the glazing help to 

prevent water intrusion when the windows are closed and locked.

Water intrusion was also observed where glazing was broken due to wind-borne debris, often where 

no shutters or plywood covering were installed prior to the storm.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-39

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-42: Concrete singlefamily home with casement 

windows. Windows seal 

around opening (red 

arrows) and lock from 

inside to prevent water 

intrusion.

Figure 3-43: Concrete 

single-family home with 

impact-resistant glazing 

covering windows and 

doors (red arrows).

3.3.2.3 Opening Protection

Buildings with opening protection generally fared better than buildings without opening protection 

during Hurricane Maria. Buildings with opening protection suffered less damage from wind-borne 

debris and wind-driven rain. Common opening protection types observed during MAT assessments 

included metal panel hurricane shutters, accordion-style hurricane shutters, and plywood panels. 
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PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Hurricane shutters offer excellent protection from wind-borne debris and are designed to prevent 

debris from penetrating openings and entering the building. Properly specified and installed 

hurricane shutters reduce the likelihood of breakage to glazing or jalousie windows. The effectiveness 

of shutters is dependent on the quality of the shutter system, proper specification for the given 

application, adequate attachment to the window frame studs, and the ability of the structural wall 

to handle the design loads. Shutter systems can be installed either during construction of the home 

or as a retrofit. 

In either case, it is important to evaluate the main building to ensure it can accommodate the 

load from the shutter system. Also, a shutter must be properly specified for its given application. It 

must be able to withstand the design pressure and debris impact forces, and it must have sufficient 

separation from the window to allow it to flex under load without breaking the window it protects.

The PRBC, and standards it references, identify the geographic areas where opening protection 

systems are required to protect glazed openings. Sections 1609.1.2 and R301.2.1.2, of the 2018 

editions of the IBC and IRC, respectively, address the Protection of Openings. These sections state 

that in wind-borne-debris regions, glazing in buildings shall be impact-resistant or protected with 

an impact-resistant covering that meets the requirements of an approved impact-resistant standard 

or the American Society of Testing and Materials (ASTM) standards ASTM E 1996 and ASTM E 

1886. Wood structural panels could be used as an alternative to provide protection so long as they 

meet local building code requirements. 

Panel attachments for residential construction in Puerto Rico are required to be designed to resist 

the component and cladding loads determined in accordance with either the 2009 IRC Table 

R301.2(2) or ASCE 7-05, with permanent corrosion-resistant attachment hardware provided and 

anchors permanently installed on the building. An amendment to the 2011 PRBC increases the 

design wind speed VASD, such that attachment in accordance with the 2009 IRC Table R301.2.1.2 

is permitted for buildings with a mean roof height of 33 feet (10.1 meters) or less where the design 

wind speed, VASD, is 145 mph (233 kph) or less, rather than 130 mph (209 kph) or less as given in the 

model code table.

The 2009 IRC references ASTM E 1996 and ASTM E 1886. Section R301.2.1.2 of the 2009 IRC states 

the following:

Glazed opening protection for windborne debris shall meet the requirements of the Large Missile Test of ASTM 

E 1996 and ASTM E 1886 referenced therein. Garage door glazed opening protection for windborne debris 

shall meet the requirements of an approved impact resisting standard or ANSI/DASMA 115.

Figure 3-44 shows impact-resistant glazing at a newer low-rise restaurant in Bayamón visited by the 

MAT, which was impacted but performed well and likely reduced further damage. Although the 

restaurant has some siding failures, it was operational and serving food at the time of the MAT visit.

While shutters perform well under ideal situations, it is important to make sure systems are well 

maintained and components are checked regularly to ensure systems remain functional. Corroded 

fasteners should be replaced, damaged rails or connection should be repaired or replaced, and 

panels should be checked for corrosion or damage. Panels are typically replaceable and may need 

to be replaced following strong storms if damaged. Figure 3-45 shows a glazed window with metal 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-41

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

panel hurricane shutters. The shutters protected the glazing; however, the window AC unit was not 

protected and allowed water to enter the building just below the window sill.

Figure 3-44: Newer low-rise 

restaurant in Bayamón with 

impact-resistant glazing 

panel (red inset) that 

performed well after being 

impacted, likely reducing 

further damage.

Figure 3-45: Metal 

hurricane shutter over 

glazed opening, (yellow 

arrow). Window unit air 

conditioner below window 

was not protected (red 

arrow) and became a 

source of water intrusion.

The residential building shown in Figure 3-46 used accordion-style shutters for the glazing on 

the second floor and traditional metal panel shutters for glazing on the first floor. Damage to the 

exterior finish of the building indicates high winds and possible debris impacts. This home was 

located near landfall of Hurricane Maria, yet all glazing remained intact.
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PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-46: Residential 

building with accordionstyle shutters (yellow 

arrows) on second 

story over glass jalousie 

windows and metal panel 

shutters (blue arrow) 

on first floor. Glass was 

protected by shutters, and 

no windows were broken. 

Exterior finish was 

damaged (red arrows).

Figure 3-47 shows a residential building near the location of Hurricane Maria’s landfall with 

hurricane shutters protecting glazed windows. Damage to exterior finish is visible, however, the 

shutters protected the glazed windows from wind-borne debris and water intrusion.

The MAT observed successful uses of plywood as protection for openings. Plywood panels offer 

considerable protection against wind-borne debris and protection for glazing or jalousie windows. 

Plywood panels may also reduce water intrusion through window openings from wind-driven rain. 

Figure 3-47: Residential 

building with metal 

panel shutters over 

windows and exterior 

doors (blue arrows). 

Damage is visible on 

exterior finish (red 

arrows).
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PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

In many cases, residents attached hurricane shutters or plywood by screwing into framing studs. 

Attaching shutters directly to window frames is strongly discouraged, because window frames are 

not designed to resist these additional loads. Rather, shutters or plywood should be installed into 

the building’s framing around window openings.

The low-rise residential building shown in Figure 3-48 has several units with different owners. The 

unit on the left used roll-down hurricane shutters to protect glazing. The unit on the right had no 

glazing protection (red arrows). Plywood was installed following Hurricane Irma. The glazing was 

broken during the hurricanes due to high winds and debris impact, damaging the contents of the 

building. This is a good example of the effectiveness of shutters to protect openings and glazing and 

what can happen when large glazed windows are not protected.

Figure 3-48: Residential 

windows, protected on 

the left (yellow arrow) 

and unprotected on the 

right, (red arrow) in Loíza. 

The unprotected windows 

were damaged and 

subsequently boarded up.

3.3.3 Roof Systems 

There was widespread roof covering damage throughout Puerto Rico. The typical failure points of 

roof coverings were from insufficient attachment of the roof covering to the roof structure (in the 

absence of a roof deck) or inadequate attachment to the roof decking. It was commonly observed 

that there was no roof decking or sheathing installed below the roof covering. Damage to roofing 

systems was widespread. The roof covering is missing entirely on the concrete building in Figure 

3-47.

The MAT observed that buildings with concrete roofs generally experienced less damage from 

wind-driven rain than buildings with wood roofs. The primary reason for this is that most buildings 

with concrete roofs observed by the MAT were constructed with sufficient mass and strength to 

withstand the wind forces, so they were less likely to be damaged or blown off. Additionally, based 

on discussions with local experts, the MAT understands that residential and low-rise buildings with 

concrete roofs in urban areas were typically professionally designed and permitted in accordance 

with building code requirements. By contrast, most wood houses observed by the MAT were built 

without input from design professionals: Wood trusses for roofs appeared to have been estimated 

and were mostly nailed, sheathing was rarely 3/4-inch (1.9 centimeters) thick, spacers and nailers 

were not used, gable ends were not braced, and any metal decking was nailed to the sheathing with 

no consideration of higher wind pressures at ends, ridges, or corners. 
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PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-49: Residential 

building missing entire roof 

covering.

Figure 3-19 showed a typical wood roof observed by the MAT that was destroyed by high winds in 

Toa Alta, allowing wind-driven rain into the building. Wood roofs attached to concrete or CMU 

walls typically have an 8-inch (20.3-centimeter) concrete beam at the top of the wall with four 

reinforcing bars placed in the concrete beam with inadequate consideration of the loading and 

poor anchorage. Wood roofs attached to wood walls frequently use hurricane clips, but with little or 

no anchorage of the wall to the floor or foundation. 

3.3.3.1 Metal Roof Covering

Many older homes in Puerto Rico have a roof covering consisting of thin corrugated metal panels 

with no structural deck beneath (Figure 3-50). These systems were often of an insufficient gauge 

(thickness) and were fastened to 2-inch-thick nailers with spans and spacing too wide to meet code 

requirements and best practices in hurricane-prone regions. 

Figure 3-50: Metal roof 

covering with no structural 

decking.
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PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

The metal roof coverings typically performed poorly and were ripped from supporting structural 

members. The connection between the panels and the building below was observed to be inadequate 

due to several factors. Improper fasteners and thin metal coverings create weak connection points. 

There was also a lack of redundancy with the connections to adequately resist the uplift forces due 

to missing or sparse decking and framing members. It appears that edge, eave, corner, and ridge 

zones did not have reinforced connections. These areas experience higher wind pressures and are 

therefore more susceptible to damage if not adequately connected. Once these areas have sustained 

damage, further roof damage often progresses that may result in the entire roof cover failing. 

In Figure 3-51, the metal roof covering and nailers have pulled away from the supporting roof 

structure. Metal roof covering panels were also often heavily corroded (Figure 3-52), resulting in 

connections weakening over time, thereby also reducing the roof’s ability to protect the buildings 

and their contents from wind-driven rain. This corrosion can be due to improper coatings, 

inadequate material selection, and age. In addition, the majority of the damaged buildings lacked 

structural decking and blocking that would provide a robust connection for the metal coverings as 

well as lateral stability, lateral load path, and secondary protection from rain.

Figure 3-51: House with 

metal roof and nailers 

pulled from its roof 

structure with no structural 

decking.

Typically, metal roof systems that performed well were those with structural decking beneath the 

corrugated panels. Figure 3-53 shows a house with a metal roof covering that sustained damage, even 

while structural decking beneath the metal protected the integrity of the roof support structure and 

the house’s contents. Small adjustments to the system used here could further strengthen the roof, 

including using a metal roof covering of sufficient gauge and using proper fasteners at a reduced 

spacing.
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PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-52: House with a 

corroded metal roof (red 

circles).

Figure 3-53: Residence 

with metal roof covering 

damage.

3.3.3.2 Tile Roof Covering

There are many types of tile roof styles, including clay, concrete, plastic, and even metal panels made 

to look like tile roof. Many older homes in Puerto Rico used traditional clay tile roofs. Tile roof 

covering performed inconsistently along the coastal areas of Puerto Rico. Some tile roofs remained 

in place, while other roofs experienced significant tile loss.

Tile roof covering is susceptible to damage and breakage from wind-borne debris. In high-wind 

regions, tiles should be mechanically fastened to the roof deck with screws; however, in many cases 

in Puerto Rico, tiles were glued using adhesive that weakened with time (Figure 3-54). 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-47

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-54: Clay roofing 

tiles inadequately attached 

to a roof with glue in 

Palmas del Mar, Humacao.

Satisfactory performance of the connections of tile roof coverage depends on using proper design 

edge, corner, overhang, and ridge wind pressures and designing the roof elements and their 

attachments to those design pressures. These areas are particularly vulnerable, and, when they have 

been compromised, the remaining areas of the roof become more susceptible to damage. 

Clay tile roof covering was often installed on wood-framed roof structures that used a wood deck 

with roofing felt beneath the nailers (Figure 3-55). This roof deck is decaying due to moisture 

infiltration at the edges and missing or inadequate flashing. 

Figure 3-55: Tiles installed 

on felt over a wooden roof 

deck. Tiles were removed, 

but the deck remained in 

place.

The presence of a roof deck helps prevent direct exposure of the building interior to water, but the 

roof deck itself is also susceptible to water intrusion and must be protected by waterproof barriers 

such as felt and flashing. While the roof deck in Figure 3-56 provided a water intrusion barrier, 

adequate fastening of the roof tiles would have alleviated some of the risk to the secondary barrier. 

Once blown off, loose tiles may themselves become debris capable of damaging other elements, 

including glazing. 
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PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-56: Tile roof 

performance with 

secondary protection from 

decking system. Tiles were 

removed, but the decking 

remained in place.

3.3.4 Topographic Effects on Wind Forces 

Many houses and other low-rise buildings constructed along hillsides and on hilltops of the 

mountainous terrain previously discussed also experienced increased wind forces during the 

hurricanes. During wind events such as hurricanes, winds associated with those storms are 

directed and channeled through mountainous terrain. As the wind moves over hills, ridges, 

bluffs, escarpments, or other topography, and up mountain valleys, the storm-induced winds often 

increase as the topography rises; much like the speed of water through a pipe increases when a 

nozzle constricts the flow. The ASCE 7 design standard provides guidance on how to account for 

this wind speed-up to determine wind loads acting on buildings. 

The MAT observed residential building damage caused by wind speed-up effects at abrupt changes 

in topography. These situations occurred on the upper one-half of hills, ridges, and escarpments. 

ASCE 7 provides design formulas and commentary which describes the situation as one in which 

the speed-up effects increase with increasing topographic feature height. As the slope becomes 

steeper, the wind speed-up also increases until it is maximized at a rise:run of 1:2. The greatest wind 

speed-up exists at the crest of the topographic feature and decreases with building height above 

ground and distance from the crest. As stated in ASCE 7-16, “Buildings sited on the upper half of an 

isolated hill or escarpment may experience significantly higher wind speeds than buildings situated 

on level ground.” (ASCE 7-16, 744).

The MAT observed buildings with significant damage likely generated by the higher wind speeds 

occurring at topographic features. In Figure 3-57, the black portions of the roofs indicate areas 

where the wind lifted clay tile roofing off the home. The roof damage became more pronounced 

proceeding up the hill. Since the homes indicate similar construction types, these residential 

buildings likely experienced greater damage because of the wind speed-up effects.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-49

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-57: Roof damage 

from wind speed-up effects 

in Palmas del Mar in 

Humacao along the eastern 

coastline.

In some situations, topographic wind speed-up on buildings can contribute to damage or even 

catastrophic failure; however, the MAT was not able to confirm the specific impacts of topographic 

effects and their quantitative contribution to these failures. Figure 3-58 shows images of a 

neighborhood atop a ridge in the mountainous region of Cayey. The strongest winds came from 

the bottom right of the aerial. Two adjacent homes (blue box) experienced significant damage, 

with one losing all four walls and the entire roof, and the other losing one wall and a good portion 

of its roof. Another home (red box) lost most of its roof covering and wood roof structure. A metal 

building system (MBS) (yellow box) was pushed over by wind forces.
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PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-58: Top, overhead view of neighborhood atop a mountainside in Cayey after Hurricanes Irma and 

Maria, showing locations of damaged buildings; below, street-level views of homes (red and blue boxes) and 

collapsed MBS (yellow box) shown in overhead. (Source: Aerial image taken October 4, 2017 [NOAA 2017]).
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-51

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Homes with informal construction appeared to suffer more extensive damage from wind speed-up. 

A home set on a hillside in Camino Nuevo, Yabucoa (Figure 3-59) experienced complete failure of 

the upper floor structure.

Figure 3-59: Complete 

failure of informal 

construction of upper floor 

structure in Camino Nuevo, 

Yabucoa.

Some residential construction performed well despite the wind speed-up effects. A cast-in-place 

concrete home in Jajome Alto, Cayey (Figure 3-60) demonstrated good performance in high winds 

even though it is located on the side of a steep slope. 

Figure 3-60: Good 

performance of cast-inplace concrete house set 

along the steep hillside of 

Jajome Alto, Cayey.
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PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

The main structure of other formally constructed houses in the vicinity demonstrated commendable 

performance in high winds. Some of these homes had informally constructed additions that did not 

withstand high winds as well. In Figure 3-61, the MAT observed partial failure of a metal canopy 

which appeared to be informally constructed. 

Figure 3-61: Hillside 

house in Jajome Alto, 

Cayey. The main building 

demonstrates good 

performance under wind 

speed-up effects, while 

the informally constructed 

canopy suffered partial 

failure (canopy debris, red 

circles).

3.4 Performance Relative to Geology (Landslide)

The MAT observed residential and low-rise buildings located in inland areas near the center of the 

Commonwealth where the topography was steeper and more mountainous. Many of the buildings 

in areas such as Utuado and Ciales are placed along roadside developments that were either carved 

into the natural slope of the existing hillside or placed on fill materials used to build up the outside 

edge of the existing hillside (Figure 3-62), resulting in a developed slope that is steeper than the 

natural slope. As the developed slope naturally weathers over time, erosion gradually occurs that 

may ultimately impact structures or roadways. In the event of a landslide, the developed slope – 

particularly one that is excessively steep – experiences a partial or complete collapse, damaging the 

roadway and other buildings on the developed slope.

Furthermore, the MAT met with local geotechnical experts and reviewed information published by 

the United States Geological Survey (USGS) in the geologic map quadrangles for San Sebastian, 

Utuado, Florida, Jayuya, Ciales, and Corozal. Based on a review of the data collected, the MAT 

found that many hillsides along Puerto Rico’s Cordillera Central, which extends from the west to 

the east-southeast on the interior of the island, tend to be formed of residual deposits from the 

weathering of intrusive rocks, metamorphic volcanic rocks, or sedimentary rocks.
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PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-62: Sample building 

placement along hillside 

development, showing 

angles of the natural 

slope and the developed 

slope. Slope angles are 

exaggerated.

Figure 3-63 and Figure 3-64 show the USGS geologic map quadrangles for the municipalities of the 

Utuado and Ciales, respectively, which the MAT visited. USGS geologic maps for other municipalities 

of Puerto Rico can be downloaded from the National Geologic Map Database, https://ngmdb.usgs.

gov/ngmdb/ngmdb_home.html.

The intrusive rocks consist mainly of (1) rocks from the Utuado pluton, composed of massive 

granodiorite, including quartz diorite, quartz monzonite, diorite and gabbro; and (2) dikes of 

granodiorite and some diorite. These intrusive rocks can be quite hard initially, but over time these 

rocks weather into more erodible materials such as sand and silt.

The volcanic metamorphic rocks include, among others, sandstones, siltstones, breccias, tuffs, and 

lava flows. These rocks tend to weather into fine soils which lose their strength with time, becoming 

unable to withstand the bedrock slope angles or the slopes provided to the cuts performed for 

development and/or road construction. 
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Figure 3-63: USGS geologic map of Utuado with location of hillside residence in Figure 3 65 (blue square). 

Modified from Nelson (1967).

Similar conditions occur with the sedimentary limestone formations prevailing alongside and 

north of the Cordillera Central. Because of these conditions, many hillside buildings were at risk 

of damage or collapse from landslides induced by heavy rainfall from Hurricanes Irma and Maria 

(Figure 3-67 and Figure 3-68).

Many homes built along the outside edge of hillsides that appear to be one- or two-story buildings 

from the road are actually two- or three-story buildings, with one or more lower levels constructed 

as walk-out basements facing out toward the hillside that are used for an additional residential 

unit. Unfortunately, this type of building is often of informal construction and does not have the 

proper supervision and guidance from geotechnical engineers who can assess the stability of the 

site or from appropriate design professionals who can provide the necessary construction details. 

As shown in Figure 3-65 and Figure 3-66, the resulting deficiencies can increase the vulnerability of 

structural failures from landslides–such as the ones that occurred during Hurricane Maria–as well 

as earthquakes.
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PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-64: USGS geologic map of Ciales, with location of hillside residence shown in Figure 3 66 (blue 

square). Modified from Berryhill (1965).
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Figure 3-65: Hillside 

residence in Cerro Gordo, 

Utuado that failed due to 

poor siting on unstable 

slope and poor connection 

of wood foundation to 

building.

Figure 3-66: House that 

failed due to landslide 

in Utuado. Source: NWS 

(2017)
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-57

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-67: Hillside house 

in Ciales at risk of landslide 

failure. The house was 

occupied despite the 

apparent risk.

Figure 3-68: Hillside mixeduse building in Ciales 

with extensive lowerlevel additions at risk of 

landslide failure.

As shown in Figure 3-69, The MAT did observe hillside residences that performed well when 

properly sited away from potentially unstable slopes and properly designed to resist potential design 

flood and wind forces. 
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Figure 3-69: Hillside 

residence in Utuado that 

was sited away from the 

edge of the slope and 

designed to resist potential 

flood and wind forces.

3.5 Successes Due to Previous Mitigation 

Puerto Rico has been impacted by many hurricanes over the decades, including Hurricanes Hugo 

in September 1989, Marilyn in September 1995 and Georges in September 1998. Several mitigation 

projects after past disasters have improved disaster resistance of residential construction in Puerto 

Rico.

3.5.1 Successes Related to Hurricanes Hugo and Marilyn Programs

June 1998, FEMA designated Culebra as the first Project Impact community in Puerto Rico. FEMA 

first introduced Project Impact in 1997 as a national initiative to help build disaster-resistant 

communities by forming public-private partnerships, assessing risks and developing action plans 

for implementing mitigation measures. In 1998, shortly before Hurricane Georges, 124 homes 

received wind retrofits from trained volunteers (FEMA 1998a). In August 2000, FEMA prepared 

a Project Impact Culebra multi-hazard risk assessment and vulnerability study (FEMA 2000). The 

study included risk assessments, vulnerability analyses, hazard maps, and recommendations to 

address flood, landslide, hurricane wind, and earthquake hazards. The recommendation that was 

given the highest priority by the study was implementing wind hazard retrofit measures for singlefamily homes in Culebra, but the MAT could not find any records that any retrofits were carried out 

by Project Impact. The MAT visited Culebra following Hurricane Maria and observed residential 

buildings that were retrofitted for wind (Figure 3-70). The Hurricane Georges BPAT (FEMA 1999) 

observed some older residences on Culebra that had been retrofitted for wind, with roof-to-wall 

metal framing connectors, but the retrofit measures were found to have not been completed within 

the few buildings observed. 
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PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-70: A homeowner 

in Culebra attempted to 

increase the resistance 

of the roof to wind uplift 

forces by means of a steel 

cable (red arrow) wrapped 

over roof members and 

anchored to a column. Such 

an addition should consider 

the design loads.

The MAT also observed several houses (Figure 3-71) that appeared to be constructed according 

to guidelines developed for a program in the U.S. Virgin Islands (USVI), the Home Protection 

Roofing Program (HPRP). The HPRP was an HMGP-funded program following Hurricane Marilyn 

in 1995 to develop wind-hazard-resistant prescriptive residential roof designs. Two HPRP solutions 

were developed, one to improve the attachment of corrugated metal roofs, the other to build roofs 

by applying a liquid-applied membrane over plywood. Both options included design solutions 

for improving the wind resistance of the joists or beams. The MAT was not able to verify that the 

observed homes in PR were constructed in accordance with HPRP guidelines, but homes that 

appeared to make use of the membrane-over-plywood construction were observed to perform well.

Figure 3-71: This home on Culebra had 

a plywood roof with a liquid-applied 

membrane consistent with the Home 

Protection Roofing Program in the 

USVI. The roof performed well.
3-60 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

3.5.2 Floodplain Acquisitions in Villa Monseratte

In 1996, after Hurricane Hortense, an HMGP-funded acquisition and relocation grant purchased 

vulnerable floodplain structures in Villa Monseratte in Arenas, Toa Baja. In Hurricane Maria, 

buildings in Villa Monseratte were flooded as high as 10 feet (3 meters), with significant wind 

damage to elevated wood-framed buildings and wood-framed upper levels of concrete buildings 

(Figure 3-72). The MAT was unable to determine if specific buildings flooded in Hurricane Maria 

were included in previous HMGP projects.

Figure 3-72: Elevated 

concrete house in 

Monseratte, Toa Baja 

subjected to flooding and 

high winds.

3.5.3 Successes Related to Hurricane Georges MAT Recommendations 

After Hurricane Georges struck Puerto Rico in September of 1998, FEMA deployed a BPAT to 

the Commonwealth to assess the storm’s impact. The Hurricane Georges BPAT Report included 

several important recommendations to reduce future building damage to residential and low-rise 

buildings in Puerto Rico. The most important of these recommendations was for “final adoption” 

and “aggressive enforcement” of a building code for the Commonwealth pertaining to residential 

construction (FEMA 1999). In 2011, Puerto Rico succeeded in adopting the 2011 Puerto Rico 

Building Code (PRBC), which references the 2009 I-Codes, including the 2009 IRC© and the 2009 

IBC©, with no weakening amendments. Unfortunately, this code adoption success has been limited 

by inadequate code enforcement, especially for residential and low-rise construction. Previous poststorm observations by MATs throughout all parts of the U.S. have consistently demonstrated that 

buildings constructed in accordance with the I-Codes and inspected for compliance perform better 

than buildings that are not code-compliant. However, the large amount of informal construction 

observed by the MAT in Puerto Rico indicates that many residential and low-rise buildings are not 

code-compliant due to a lack of professional design input and construction inspections to verify 

compliance. The Commonwealth of Puerto Rico understands the importance of this issue, as 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-61

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

evidenced by the recent passage of the Permitting Reform Act (Law 19-2017) in April 2017, which 

created the Unified Information System to streamline the permit application process.

In addition to code adoption and enforcement, the Georges MAT also recommended education 

and outreach to homeowners on the risks of building in flood-prone areas. Although the FEMA 

Region II Coastal Outreach Advisory Team provided some floodplain education in Puerto Rico in 

2013, the success appears to have been limited in communicating the risk to residents. This is shown 

by the large amount of residential and low-rise commercial development observed by the MAT in 

coastal and riverine floodplains throughout the Commonwealth. Additionally, recent studies have 

shown that despite the widespread availability of flood insurance in Puerto Rico, mostly from 

private insurers, fewer than 4 percent of households in Puerto Rico have flood insurance (Kousky 

and Lingle 2018). By contrast, the percentage of U.S. homeowners overall having flood insurance is 

approximately three times greater (Insurance Information Institute 2016).

The New Secure Housing Program (NSHP), established in 1998, replaced vulnerable buildings 

in 15 municipalities with concrete houses, ultimately building 1,647 housing units. The MAT 

and Pre-MAT visited several of the NSHP communities, including Campanilla (Figure 3-73) and 

Brisas De Campanero in Toa Baja, Riberas Del Bucana in Ponce, Villa Alegria in Vega Alta, and 

Santo Domingo y Pellejas in Morovis. The NSHP housing units at these locations were typically 

one- and two-story reinforced concrete residential houses with concrete roofs, such as the house 

in Campanilla shown in Figure 3-74 and Figure 3-75. The NSHP buildings observed by the MAT 

performed well and resisted flood and wind damage from Hurricanes Irma and Maria better than 

most of the residential and low-rise buildings surrounding them. However, some of the Campanilla 

buildings experienced flooding depths of 1-3 feet (0.3-0.9 meters) above grade during Hurricane 

Maria (Figure 3-73). The community was elevated on fill to the BFE but experienced flood levels 

exceeding the 500-year flood (Figure 3-76). The community was isolated after roads flooded. 

Additional freeboard could have mitigated damage to these buildings. A minimum of one foot (0.3 

meters) of freeboard is required for residential buildings in the SFHA by Planning Regulation 13. 

Some NSHP houses in Campanilla suffered damage to aesthetic components including clay tile 

roof coverings blown off by wind (Figure 3-74). One NSHP house had an informally constructed 

addition that lost its roof covering (Figure 3-75) due to wind. Some NSHP houses in Santo Domingo 

y Pellejas suffered minor roof leaks due to heavy rainfall and improperly maintained rooftop drains. 
3-62 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

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Figure 3-73: Aerial image of Campanilla NSHP community, Toa Baja. The community was elevated on fill, 

resulting in isolation of properties during Hurricane Maria due to flooding of surrounding areas. Homes on the 

southern portion of the community experienced shallow flooding. Zone AE. Inset, NSHP home in Campanilla 

showing approximate inundation depth (yellow line).

Local officials in Toa Baja told the MAT that some buildings acquired in previous Hazard Mitigation 

Assistance (HMA) acquisitions had later been reinhabited. While the MAT was unable to confirm 

this statement, it is possible that some homes were not razed or properties not deed-restricted per 

grant requirements. A 2015 audit report by the Department of Homeland Security Office of the 

Inspector General found that the PRDOH “did not complete the demolition and/or deed restriction 

requirements for 309 of the 1,364 [NSHP] off-site program participants who received replacement 

housing under the award” (Department of Homeland Security Office of Inspector General 2015). 

It is not known whether the problems identified in the 2015 report were successfully addressed. 

Reoccupation of acquired homes exposes the occupants to continued flood risk. 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 3-63

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-74: This NSHP 

house in Campanilla Toa 

Baja suffered damage to 

aesthetic components 

including clay tile roof 

coverings and decorative 

eaves blown off by wind.

Figure 3-75: NSHP house 

in Campanilla has an 

informally constructed 

addition which lost its 

entire roof covering.
3-64 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF RESIDENTIAL AND LOW-RISE BUILDINGS

Figure 3-76: A Portion of the 2009 effective FIRM for Campanilla, Toa Baja, with locations of NSHP homes 

shown in Figure 3-73 (orange box), Figure 3-74 (red box), and Figure 3-75 (yellow box).
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 4-1

4

HURRICANES

IRMA AND MARIA

IN PUERTO RICO

MITIGATION ASSESSMENT TEAM REPORT

Performance of Schools and 

Shelters

School facilities were heavily impacted and damaged by 

Hurricanes Irma and Maria.

Damage to public schools was reported to be as high as $8.4 billion across Puerto Rico (Brown 

2018). Prior to the landfall of Hurricanes Irma and Maria, the Puerto Rico Department of Education 

(PRDE; Departamento de Educación) was responsible for the management of almost 1,200 schools, 

supporting approximately 350,000 students, across 78 municipalities. Public schools are under the 

jurisdiction of PRDE, but the public schools are maintained by a combined effort from PRDE, the 

Puerto Rico Public Buildings Authority (Autoridad de Edificios Públicos de Puerto Rico) and the 

local municipalities. 

4.1 Summary of School and Shelter Performance

On September 21, the day after Hurricane Maria made landfall, all school buildings were closed 

except those being used as shelters, and impacts to school facilities were widespread. While this was 

not unexpected based on the magnitude and intensity of the hurricane, the ability of schools to 

reopen after the storm was more difficult than many had anticipated. By mid-October, 98 schools 

had reopened, or roughly 9 percent (Alvarez 2017), but it was not until early December that 1,075, 

or more than 90 percent, of the schools reopened. During that time, many schools opened with 

water and basic school services, but a number of buildings were reopened without power, or without 
4-2 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF SCHOOLS AND SHELTERS

full power, limiting some of the activities at the schools. PRDE reported that 38 schools have been 

identified as unable to be reopened due to building damage that they would not repair. 

The MAT visited several schools across the Commonwealth (Figure 4-1). Most of the schools visited 

had a core (primary) building that was constructed of multi-story reinforced concrete-framed or 

CMU walls with reinforced concrete roof decks. Additional buildings for supplemental classrooms 

or administrative office functions were of multiple construction types, including concrete or 

masonry buildings with steel-framed roof systems, metal building systems (MBSs), and other lightframed construction.

Figure 4-1: Schools visited by the MAT and discussed in this report. Schools with an asterisk were designated 

for use as shelters.

The most commonly observed impacts to schools, including those used as shelters, were the 

following:

● Water intrusion through the roof and windows (openings)

● Loss of power and communications, with the resulting loss of HVAC systems support, due to

■ Loss of grid power

■ Lack of backup/emergency generator power on-site

■ Damage to the backup/emergency generator on-site
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 4-3

PERFORMANCE OF SCHOOLS AND SHELTERS

The additional impacts below were observed at a number of school buildings but were not as 

common as those notes above:

● Significant damage to building envelope (roof, wall, and window systems and assemblies)

● Site and facility flooding

● Significant structural damage to facilities (due to flood and wind impacts)

● Facility access problems

The following sections present MAT observations related to flood and wind impacts to school 

facilities. The last section of the chapter presents information on the Puerto Rico Department of 

Housing (PRDOH; Departamento de Vivienda) program to manage shelters before, during, and 

after a hurricane makes landfall. 

4.2 Effect of Siting on the Performance of School Buildings

While the majority of damage to school facilities was caused by wind and wind-borne debris, some 

schools were damaged by floodwaters from storm surge, localized flooding from rainfall in lowlying areas, and riverine flooding in mountain areas. 

In support of the MAT, FEMA was provided information on damage to a number of school and 

municipal buildings. Based on the damage reported to FEMA and the reported information on 

flooding and damage, the MAT visited a number of schools in support of this assessment. The MAT 

did not visit all damaged schools, however. 

The damage and observations for the schools 

presented in this section, and throughout 

this chapter, are presented to provide an 

understanding of typical impacts to school 

buildings and to highlight successes and failures 

of building performance. 

The MAT did not observe siting problems 

related to landslide or slope stability hazards for 

schools. These buildings are typically located 

on larger parcels and as a result are not located 

on hillsides or escarpments1. The MAT also did 

not observe any schools in coastal flood zones.

A program administered by PRDOH evaluates 

buildings, including schools, for use as shelters/

refuge areas pre-event, during the event, and 

REOPENING OF PUERTO RICO SCHOOLS 

POST-MARIA

After Hurricanes Irma and Maria, the U.S. Army 

Corps of Engineers (USACE) performed assessments of the more-than-1,100 schools across 

Puerto Rico in support of the Government of 

Puerto Rico and PRDE. Public schools were not allowed to reopen unless they were assessed and 

given approval to reopen by PRDE. These assessments were performed independently of FEMA’s 

MAT efforts. This section focuses on MAT observations of building performance and impacts to 

school buildings from the flood and wind events. 

1Although the structures were not impacted by landslide, Escuela Juan D. Stubbe school in Cidra did lose part of its 

perimeter fence and part of a running track to landslide.
4-4 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF SCHOOLS AND SHELTERS

post-event. PRDOH informed the MAT that no public schools used as shelters were in a mapped 

Special Flood Hazard Area (SFHA). 

Prior to the 2017 hurricanes, due to efforts by PRDE and PRDOH, the number of schools in SFHAs 

was reduced, but some schools are still located in flood-prone areas. The MAT visited the Luis M. 

Santiago School in Toa Baja, a combined elementary, junior high, and special education school 

shown in Figure 4-2. Prior to Hurricanes Irma and Maria, this was one of three schools in Toa 

Baja Pueblo (Old City/Downtown) that were chosen as the sites for school consolidation. The three 

schools chosen to remain open were Jose Robles Otero Elementary School, the Luis M. Santiago 

School, and Adolfina Irizarry de Puig School, the latter two of which are located in the mapped AE 

Zone on the portion of the FIRM shown in Figure 4-3. 

Figure 4-2: Mud remains 

in a classroom that was 

flooded (yellow line) at the 

Luis M. Santiago School, 

located in Zone AE.

Schools in other locations throughout Toa Baja closed, and many of their students were consolidated 

to schools in Toa Baja Pueblo. However, the MAT could not determine if the flood, wind, or seismic 

vulnerabilities of the schools were criteria in this consolidation effort. This contrasts with the 

municipality’s approach to the repetitive flood issue at the old Toa Baja Municipal Building (Figure 

4-3). In 1995, when a new building was needed, the municipality moved operations to a new building 

in a location that was believed to be less vulnerable to flooding. Although it is partially in the SFHA 

on the effective FIRM (Figure 4-4), the building is elevated on fill.

Schools located toward the central portion of the island of Puerto Rico were protected from 

storm surge but not from flooding related to site drainage or rising waters along tributaries. At 

the Eduardo Garcia Carrillo High School in Canóvanas (Figure 4-5), the river in the forefront of 

the photo overflowed its banks and flooded the roadway in front of the school and its parking lot. 

Fortunately, floodwaters did not enter the school itself, as it is constructed atop a small rise on the 

site. The extent of the flooding (the edge of the parking school lot) is at the AE Zone boundary. 

Thus, the flood was exactly the base flood in this location, and a small increase would have flooded 

the school.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 4-5

PERFORMANCE OF SCHOOLS AND SHELTERS

Figure 4-3: A portion of the effective 2009 FIRM showing the old Toa Baja Municipal Building (upper yellow 

box) and Luis M. Santiago School (lower yellow box).

Figure 4-4: A portion of the effective 2009 FIRM showing the new Toa Baja Municipal Building. The facility 

was relocated in 1995 to reduce flood risk; however, it is partly located inside the SFHA.
4-6 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF SCHOOLS AND SHELTERS

Figure 4-5: Floodwaters 

from the stream under this 

bridge rose to the edge 

of the mapped Zone AE 

(yellow line) in the parking 

lot immediately adjacent to 

the school. The floodwaters 

did not enter the school.

4.3 Performance Relative to Flood

The majority of damage at schools observed by the MAT was wind-related damage. However, some 

schools are still located within SFHAs and are vulnerable to flooding during hurricanes and other 

severe rain events. The majority of the schools visited by the MAT were located outside of the SFHA 

and did not experience flooding or flood damage within the school buildings. However, a few 

schools were in areas with poor site drainage or were within the SFHA itself. Most of the schools that 

were in the SFHA experienced some level of flood inundation during Hurricanes Irma and Maria.

4.3.1 Elevation and Freeboard

Two of the schools visited by the MAT were located within the SFHA and were flooded during 

Hurricane Maria. Luis M. Santiago School in Toa Baja includes one- and two-story slab-on-grade 

concrete buildings built in 1950 and has a student population of approximately 350. During Maria, 

the school buildings were flooded inside to a depth of approximately 4–5 feet (1.2–1.5 meters) above 

grade, judging from high-water marks (Figure 4-6 and Figure 4-7). Flood damage was widespread 

across all classrooms on the ground level.

This school was constructed long before the development of the FIRMs. The hazard information 

available at that time, perhaps limited to some information on historical storms, probably explains 

why the buildings were not elevated to provide some level of protection against expected floods. 

There was no significant elevation of the buildings above the adjacent grade.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 4-7

PERFORMANCE OF SCHOOLS AND SHELTERS

Figure 4-6: Luis M. Santiago 

School with location of high 

water mark (yellow line) 

from Maria.

Figure 4-7: Classroom at 

Luis M. Santiago School 

with high-water line 

indicated (yellow line).

Adolfina Irizarry de Puig School in Toa Baja also experienced flooding. The school accommodates 

approximately 600 students and is located adjacent to the La Plata River. The main building, built in 

1978, is the three-story concrete building shown in Figure 4-8. The building is elevated and appears 

to have been retrofitted for earthquakes; however, there was one set of rooms below the elevated 

main floor. 
4-8 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF SCHOOLS AND SHELTERS

During Maria, the river overflowed its banks and the areas beneath the elevated school experienced 

2.5–3 feet (0.8–0.9 meters) of flooding. The flooding resulted in several feet of water, mud, and 

sediment being deposited into the non-elevated student center (Figure 4-9) underneath the elevated 

building. At the time of the MAT visit, the facility was not able to reopen due to flood damage, lack 

of power, and lack of fresh water at the site. In addition to flood damage at the site, wind and winddriven rain damage included HVAC equipment damage and water damage (infiltration) on the 

third floor from roof leakage. The water intrusion problem occurred when water trapped on the 

roof (ponding) leaked into upper floor classrooms, damaging accounting and computer equipment.

Figure 4-8: Adolfina Irizarry de Puig 

School building partially elevated with 

bracing added as seismic retrofitting. 

Wind damaged these HVAC units. The 

school received 2.5 - 3 feet of flooding 

(yellow line).

Figure 4-9: Toa Baja High School 

building student center area 

underneath the elevated building 

that flooded during Maria. The school 

received 2.5- 3 feet of flooding (yellow 

line).
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 4-9

PERFORMANCE OF SCHOOLS AND SHELTERS

4.3.2 Mechanical, Electrical, and Plumbing Systems Performance

The flood damage at the Luis M. Santiago School also included flooding of electrical equipment at 

the school (Figure 4-10). Because the flooding in the buildings was over 4 feet (1.2 meters) in depth, 

the flooding impacted the electrical system across the first floor.

Figure 4-10: High water 

mark on wall (red arrow) 

and electrical panel at the 

Luis M. Santiago School. 

Flooding of the electrical 

panel impacted the 

electrical system across 

the first floor.

4.4 Performance Relative to Wind

The MAT visited over a dozen schools in the mountains, the coastal areas, and foothills to observe 

their performance during the hurricanes. At the sites visited by the MAT, no school building was 

observed to have experienced complete structural failures, with one notable exception: There were 

several partial to complete collapses of MBSs used as covered basketball courts and athletic areas. 

Most of the schools visited were constructed from reinforced concrete or reinforced CMU, with 

concrete roof decks. Some schools had concrete or CMU walls with metal roof decks, and some were 

steel-framed. Some schools employed MBSs as additional buildings on school campuses.

The good structural performance of these buildings contrasted in some cases with the poor 

performance of lighter structural components or building envelopes due to wind pressures or windborne debris from Hurricanes Irma and Maria. The poor performance or failures of components 

and cladding led to widespread water intrusion at school facilities. Water intrusion usually began at 

roof coverings which appeared to be older and past their design life or at window assemblies that 

were not designed or rated to resist wind-driven rain or wind-borne-debris impacts. 

Windows at school buildings varied in type, glazing, and debris impact resistance. The most common 

window systems were metal panel jalousie windows which had not been tested for debris impact 

resistance and are not rated for resistance to water intrusion. Where glazed windows systems were 
4-10 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF SCHOOLS AND SHELTERS

used, it did not appear the windows were rated to resist wind pressures associated with the design 

wind speed or for water intrusion resistance. Additionally, most of the glazed window systems were 

not observed to use impact-resistant glazing and were not protected with an impact-resistant shutter 

system.

Significant water intrusion from the window and roof covering failures, combined with the lack of 

grid power or backup/emergency power at the facilities, was the primary reason most schools took 

weeks or months to reopen after the storms. The ability to keep water out of the buildings and the 

power on are vital for rapid recovery. 

4.4.1 Main Wind Force Resisting System

Newer schools constructed of reinforced concrete performed well with only minor water intrusion 

through windows. However, some newer facilities experienced more significant water intrusion when 

roof coverings or roof-mounted equipment (including exterior mounted ductwork) did not perform 

as designed. These buildings were observed to be load-bearing or shear wall construction or multistory framed construction. The buildings were likely all professionally designed and engineered, 

and those constructed within the last 20 years appeared to have been designed with consideration 

of gravity loads as well as wind, flood, and seismic loads. The MAT observed that these buildings did 

not experience structural failures within the MWFRS due to wind forces alone. In general, these 

larger buildings had a continuous load path that resisted wind loads without failure, as was the case 

at Loíza Vocational High School (Figure 4-11). Exceptions to this good performance were observed 

in MBS buildings used for athletic facilities.

Figure 4-11: Loíza 

Vocational High School 

was constructed in 2010 

and did not experience 

structural damage to the 

MWFRS from Hurricanes 

Irma and Maria.

 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 4-11

PERFORMANCE OF SCHOOLS AND SHELTERS

The MAT also visited roughly a dozen older school buildings constructed from the 1950s to the 1990s. 

Eduardo Garcia Carrillo High School, constructed in 1988 in the lower elevations of Canóvanas, a 

mountainous region, performed well with no damage to the reinforced concrete buildings at the 

site (Figure 4-12). Storm impacts to these buildings comprised water intrusion through jalousie 

window assemblies and water intrusion from clogged drainage elements of the roof. Large roof 

drainage troughs around the perimeter of the school backed up and filled with water when drains 

were clogged by wind-borne debris. This school also had two metal buildings used for vocational 

classrooms. The MWFRS performed well without damage, however, both buildings experienced 

ridge cap loss and wind-borne-debris impacts leading to significant water intrusion in these building 

areas. 

Figure 4-12: Eduardo Garcia Carrillo High School, left, did not experience structural failures to reinforced 

concrete classroom buildings. Damage at these buildings was due to water intrusion from the roof, right, and 

through windows.

BACKUP AND EMERGENCY POWER AT 

SCHOOL BUILDINGS

Most of the schools visited by the MAT had no 

generator for emergency power or backup power. This included some school buildings that were 

identified by PRDV for use as shelters. 

The lack of backup and emergency power impacted the ability of the municipalities and PRDE to 

reopen schools after Irma and Maria; especially 

when the school buildings were unable to receive 

primary power from the grid. With no ability to 

provide power for lighting, water and sewer services, and air conditioning (where present), school 

reopenings were delayed. 

The most notable failure of the MWFRS 

observed at school buildings were at one- and 

two-story buildings that had roof systems 

constructed of materials other than reinforced 

concrete. Several examples of partial roof 

failures in steel-framed roof systems with metal 

roof decks were observed. While the rest of the 

MWFRS performed well, some of these lighter 

roof decks experienced uplift failures (at corner 

and edge zones where wind loads are highest). 

Figure 4-13 shows the interior and exterior of 

the Gutierrez Elementary School in Canóvanas. 

The school buildings were single-story 

reinforced concrete buildings constructed in 

the 1950s. In the 1970s, several of the buildings 

received second-floor additions. The MWFRS 

of the first- and second-floor walls and roofs 

performed well structurally, with no observed damage to reinforced concrete classroom sections, 

although water intrusion from wind-driven rain through jalousie window assemblies was observed. 
4-12 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF SCHOOLS AND SHELTERS

However, some roof deck damage was observed to one portion of the second-story classrooms 

(Figure 4-13, right). Some metal purlins were damaged and displaced, and the metal roof deck 

failed from wind uplift. 

Figure 4-13: Gutierrez Elementary School experienced loss of metal roof deck panels and some purlins from 

wind uplift.

The MAT observed that many MBS buildings performed well, with no structural damage to the 

MWFRS and little or no damage to the metal panel upper wall and roof covering systems. At a 

vocational school in Loíza, two of these MBS facilities were located next to each other and performed 

well with no observed damage from the hurricanes (Figure 4-14). However, others failed due to wind 

pressures. These include the Felix Pedraza Athletic Complex in Ceiba (Figure 4-15). Parts of the 

MWFRS of this MBS were damaged as a result of high winds, as steel girders exhibited deformation 

of the flanges, a column was twisted, and the CMU infill wall partially collapsed. The building also 

lost much of its wall cladding and metal roof paneling. 

Figure 4-14: Two MBSs 

used as athletic facilities 

at Loíza Vocational High 

School that performed 

well and were not 

observed to have wind 

damage from Hurricane 

Maria.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 4-13

PERFORMANCE OF SCHOOLS AND SHELTERS

Figure 4-15: The Felix 

Pedraza Athletic Complex 

in Ceiba experienced 

cladding failures and 

partial failure of its 

MWFRS.

By contrast, several MBS athletic buildings were observed to have failed due to section loss from 

corrosion near the base plates of the framed buildings. (Figure 3-58, Figure 4-16). The MBS athletic 

facility shown in Figure 4-16, located at the high school in Ceiba, experienced a failure of part of 

the MWFRS at the end bay of the building. The base of the end column experienced significant 

section loss and failed as result. The section failed at the bolted connection, but the section also had 

completely lost additional web material that was observed as a hole in the web of the steel section 

(red arrow).

Figure 4-16: Left, the end bay of this MBS athletic facility failed when it could not resist wind pressures during 

Hurricane Maria. Corroded structural members, right, likely contributed to the failure. In this column, a hole 

had formed in the web (red arrow).

When the bases of framed buildings are not properly designed and constructed, materials can 

be exposed to standing water and other environmental conditions that result in degradation of 

structural properties. When structural members corrode or are compromised by other types of 

damage, they lose their ability to perform as designed and may fail.
4-14 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF SCHOOLS AND SHELTERS

4.4.2 Building Envelope Damage to Windows and Openings

The building envelope consists of the non-structural (components and cladding) elements of a 

building, including infill walls; wall cladding; roof coverings; windows; doors; and small structures 

attached to the building, such as penthouses and awnings. This section presents MAT observations 

on the performance of windows, window assemblies, and openings in school facilities. 

In all schools observed by the MAT, some or all openings were designed to be less than fully 

enclosed, meaning they were not air- or watertight. Sealed window assemblies tested and rated to 

resist wind pressure and water intrusion were observed only in some portions of school buildings or 

not at all. The most commonly observed window systems were metal panel jalousies (Figure 4-17). 

The MAT observed that, in the classrooms and large open spaces of the schools, the metal panel 

jalousies typically had screens behind the louvers. However, in administrative offices, libraries, 

computer rooms, and other areas requiring air conditioning, plexiglass or plastic panels were 

installed on the inside of the jalousie assemblies for better control of moisture and temperature 

in the air-conditioned spaces. The windows along the first floor of the school shown in Figure 4-18 

were backed with plexiglass panels for benefit of the laboratory classrooms. This school was used as 

a shelter during both Irma and Maria despite not being equipped with backup power. The school 

lost power during Irma and was still without power when the MAT visited in October 2017.

Figure 4-17: Metal panel 

jalousies at this school 

were backed with screens 

across the second-floor 

classrooms and with 

plexiglass panels on the 

first-floor laboratory 

areas.

At the schools visited by the MAT, none of the jalousie assembles had been blown out of their 

anchorages in the walls, although some glazed windows experienced that failure mode in both 

residential buildings and critical facilities. Some of the jalousies had damage from wind-borne 

debris impacts, but no complete failures of the jalousie assemblies were observed; this was observed 

even though none of the metal panel jalousies appeared to be rated for debris impact resistance 

(there was no testing or approval label on the assemblies). Rather, damage was primarily due to 

water intrusion through the jalousie panels and into the classroom, office, library, or laboratory 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 4-15

PERFORMANCE OF SCHOOLS AND SHELTERS

spaces. Secondary damage was observed to the jalousies themselves; many were inoperable due to 

being bent or damaged from wind pressures or wind-borne debris impacts during the hurricanes. 

Figure 4-18: Metal panel 

jalousie windows at 

Georgina Baquero High 

School, constructed in 

1989. These windows are 

used across the entire 

exterior for classrooms 

and offices. This wing of 

the school was used as a 

shelter during Hurricanes 

Irma and Maria.

Rooftop skylights were observed by the MAT at several schools. Failures observed were both from 

wind pressures removing the windows from the roof as well as glazing breakage from wind-borne 

debris (Figure 4-19). 

Figure 4-19: Broken 

skylight glazing at a high 

school in Canóvanas.
4-16 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF SCHOOLS AND SHELTERS

4.4.3 Roof Coverings

A variety of roof coverings were observed at the schools visited by the MAT, including metal 

panels, liquid-applied membrane over concrete roof deck, and single-ply and modified bituminous 

membranes. Metal panels included exposed fastener systems (corrugated metal panels and 

R-panels). The most common observed roof covering was modified bitumen.

Performance of the roof coverings was generally poor. While widespread delamination or blow-off was 

not observed, many of the roof coverings were old and at or past their design life. Old roof coverings 

had shrunk and separated from the roof deck and other roof materials, peeling up in multiple 

small areas, and had punctures from wind-borne debris. Figure 4-20 shows two views of the roof 

covering at the Georgina Baquero High School. This roof had a modified bitumen covering that was 

only two years old, according to school staff. The roof covering performed well and was reported 

to have no water intrusion. This was the only roof that the MAT observed that was less than 8 years 

old. The hot-applied flashing (Figure 4-20, right) extended from the roof surface up and over the 

parapet. Note the water tanks (Figure 4-20, left, red circle); wind forces broke these tanks free, and 

they were no longer secured to the roof structure or the piping systems of the building. 

Figure 4-20: Modified bitumen roof covering at a school in Canóvanas. Left, water tanks (red circle) broke free 

of their attachments. Right, the roof covering is terminated and flashed on the backside of the parapet. This 

roof was approximately 2 years old and performed well during both Irma and Maria.

Figure 4-21 shows the roof covering at Loíza Vocational High School. This covering was eight years 

old and had experienced performance problems during the storm. The roof covering was punctured 

and had areas of separation at joints, resulting in some water intrusion through the covering. Note 

in Figure 4-21 (right) that the roof flashing is on the back of the parapet versus over the top of the 

parapet in Figure 4-20. The flashing in Figure 4-20 and Figure 4-21 remained in place during the 

hurricanes.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 4-17

PERFORMANCE OF SCHOOLS AND SHELTERS

Figure 4-21: Modified bitumen roof covering at a high school in Loíza.

Figure 4-22 shows Jose Robles Otero Elementary School in Toa Baja. Roof damage at this school was 

primarily due to the loss of roof flashing (red circle). Water damage was observed related to roof 

flashing loss. The roof flashing was mechanically secured at the top edge of the roof and appeared 

to lack adequate fasteners to resist wind uplift. School staff indicated there was no flood damage 

to the school during Irma nor Maria, but the facility did lose power. Additional roof damage at the 

school included the failure of a metal awning (Figure 4-23). 

Figure 4-22: Jose Robles Otero Elementary School. Left, façade; right, roof with lost flashing (red circle).
4-18 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF SCHOOLS AND SHELTERS

Figure 4-23: Collapsed 

awning from wind uplift 

at Jose Robles Otero 

Elementary School

Several campuses visited by the MAT had buildings with metal panel roof coverings. These coverings 

were observed to be part of MBS used at the sites. These panel roof systems performed reasonably 

well when properly secured to the roof purlins or roof decking. Figure 4-24 shows MBS buildings 

used for classrooms at Eduardo Garcia Carrillo High School in Canóvanas. The panels at this school 

were well secured; however, trim and ridge caps were not (red circle). In several locations these 

ridge caps blew off, leading to significant water intrusion into the classrooms below.

Figure 4-24: Older MBS at 

Eduardo Garcia Carrillo 

High School in Canóvanas. 

These roofs performed 

well except for ridge cap 

loss and damage from 

falling trees.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 4-19

PERFORMANCE OF SCHOOLS AND SHELTERS

Culebra Ecological School also used a metal panel roof system (Figure 4-25). While most of the roof 

was not damaged, several areas did experience damage. This school, constructed after Hurricane 

Georges on Culebra, is located within 1,500 feet (460 meters) of the coast and exhibited notable 

corrosion that affected roof performance. In addition to the weakening of roof elements due to 

corrosion, the metal panel roof covering experienced damage at some locations along the edge 

zones of the roof. This roof damage appeared to be because of inadequate fasteners on the roof. 

Figure 4-25 (left) shows where the roof performed well and where the edges of the roof panels were 

secured by two rows of fasteners (blue arrows). In contrast, Figure 4-25 (right) shows where the roof 

panels failed, resulting in water intrusion and damage to the adjacent photovoltaic (PV) panels. 

The roof panels in this location had only one row of fasteners along the roof edge (red arrow). This 

school also functioned as the main shelter in Culebra and was used during both Irma and Maria. 

Figure 4-25: Roof covering with two rows of connections near edge of roof covering, left, performed better 

than roof covering with only one row of connections near edge, right.

The Palmas Academy in Palmas del Mar (Figure 4-26) was the only school the MAT observed with 

a tile roof covering. This school had a combination of tile roof coverings and modified bitumen on 

the flat roof sections. The tile roof covering did not perform well, and in many locations the tile 

covering was lost; however, the MAT could not determine if the tile failed from wind pressures or 

wind-borne debris impact. 

Figure 4-26: Tile roof failure at The Palmas Academy in 

Palmas del Mar.
4-20 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF SCHOOLS AND SHELTERS

4.4.4 Rooftop Equipment

The MAT observed that rooftop equipment had variable performance. While some systems were 

anchored and remained in place during the hurricanes, many equipment pieces did not. Failures 

of three types were observed: failure of the equipment itself, failure of support stands or curbs, and 

failure of guy wires. Failure of the equipment itself caused not only loss of the mechanical units but 

water intrusion into the building from the failed equipment. This type of failure was observed at 

The Palmas Academy (Figure 4 27, left) and Loíza Vocational High School (Figure 4-27, right).

Figure 4-27: Two examples of rooftop equipment failure that allowed water to enter the building. Left, wind 

removed an HVAC unit access panel at The Palmas Academy. Right, a toppled vent stack (yellow arrow) 

allowed water intrusion into the building (red arrow) at Loíza Vocational High School.

Many rooftop equipment units were observed to have blown off their curbs or stands on the roof. 

Figure 4-28 (left) shows parapet walls at Jose Robles Otero Elementary School that were meant to 

block the wind and help protect this rooftop unit; however, most units at this school did not have 

parapet walls and were simply blown off curbs and stands to which they had been inadequately 

secured. 

Figure 4-28: Left, Jose Robles Otero Elementary School had concrete walls that may have shielded rooftop 

equipment from wind. Right, small rooftop equipment at Eduardo Garcia Carrillo High School in Canóvanas 

was not properly secured and was displaced by wind forces from Maria.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 4-21

PERFORMANCE OF SCHOOLS AND SHELTERS

Some schools provided additional tie-downs for rooftop equipment with guy wires (Figure 4-29). 

The failed connectors can be seen at the bottom left of the photo. The fasteners used on the guy 

wires were not stainless-steel connectors. While these connectors were less than 10 years old, they 

failed due to corrosion. Building materials, especially connectors, are vulnerable to corrosion 

and premature failure when used near the coast. This school is located less than one mile (1.6 

kilometers) from the ocean.

Figure 4-29: Vent stacks 

secured with guy wires 

at Loíza Vocational High 

School were toppled by 

high winds when the 

threaded adjustment 

connectors failed due to 

corrosion, leading to water 

intrusion in the building.

4.5 School Facilities Used as Event-Specific 

and Post-Event Shelters

The PRDOH manages and maintains the primary program for identifying and managing 

hurricane evacuation shelters across the Commonwealth. The program evaluates and tracks 

buildings and facilities to be used as “event-specific” shelters and post-event shelters. Assessments 

are conducted on a yearly basis by representatives from PRDOH, PRDE, and the Puerto Rico State 

Agency for Emergency and Disaster Management (Agencia Estatal para el Manejo de Emergencias 

y Administración de Desastres, informally the Puerto Rico Emergency Management Agency 

[PREMA]). Prior to Hurricanes Irma and Maria, PRDOH evaluated 499 buildings and facilities 

for use as event-specific and post-event shelters. From this group of identified buildings, 383 school 

buildings had been evaluated and identified for use as event-specific shelters. These event-specific 

shelters or hurricane evacuation shelters are buildings, or portions thereof, to be used during a 

storm to provide refuge for the residents of a municipality during a hurricane or major storm event. 

However, of all the buildings in the PRDOH shelter inventory, none of the shelter facilities (or 

portions of facilities) were purpose-built safe rooms or storm shelters defined by the FEMA P-361 

criteria or the ICC 500© standard, respectively. 
4-22 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF SCHOOLS AND SHELTERS

4.5.1 School Shelter Performance

The MAT visited three schools that were used as shelters or were on a primary or secondary shelter 

list maintained by PRDOH:

1) Georgina Baquero High School, Canóvanas (constructed in 1989)

2) Culebra Ecological School, Culebra (constructed in the early 2000s after Hurricane 

Georges)

3) Vocational High School, Loíza (constructed in 2010)

SHELTERS AND AREAS OF REFUGE

Chapter 2 presented the terms Safe Rooms and Storm Shelters to refer to purpose-built buildings (or portions 

thereof) designed to provide life-safety protection during hurricanes. However, there are different uses of the 

word “shelter” in emergency preparedness and emergency response. In Puerto Rico, PRDOH works with PRDE 

and the municipalities to identify school buildings to be used by residents who do not want to stay in their 

homes during a storm event and to come to after a storm event if their homes have been damaged.

While these buildings provide an organized location to take refuge from the storm with some emergency services such as food, water, and cots to sleep on, it should be noted that the buildings identified as shelters were 

not designed or constructed to provide life-safety protection from flood or wind events. Further, these facilities are assessed for the ability to support the operations, the facilities in the DOH shelter program are only 

evaluated with a minimal assessment, and in most cases, the structural systems and the building envelope systems have not been evaluated for their vulnerability or susceptibility to damage from flood waters, extreme 

winds, or wind-borne debris. The presumption that these larger buildings, or public buildings, will perform 

better during hurricanes and tropical storms may be incorrect for several reasons. If the building has not been 

evaluated for its ability to resist flood and wind loads without damage or collapse, the ability of the shelter to 

provide a safe area of refuge cannot be defined or confirmed prior to a storm event. 

These emergency shelters, recovery shelters, and post-event shelters are simply a place of refuge and should 

not be considered to be able to provide the same level of protection as a FEMA 361 Safe Room or an ICC 500 

©compliant storm shelter. Guidance from FEMA can be applied to evaluate buildings proposed for use as shelters or at least to provide a best available refuge area when a storm approaches.

4.5.1.1 Georgina Baquero High School, Canóvanas

Numerous classrooms at this high school in Canóvanas were designated for shelter use by PRDOH 

and used during both Hurricanes Irma and Maria (Figure 4-30). While the concrete walls and roof 

of this building provided some level of protection for the occupants, the facility was not designed 

for life-safety protection and was not supported by a backup or emergency generator. No generator 

was present on-site, and there is no pre-wired connection panel to connect to a temporary backup 

generator. Power was lost during Hurricane Irma, and despite this, the school was operated as a 

shelter during both events. The metal panel jalousies on all exterior windows were not designed or 

rated to provide debris impact protection and were also the failure points for the building envelope 

that allowed water intrusion into the shelter spaces. 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 4-23

PERFORMANCE OF SCHOOLS AND SHELTERS

Figure 4-30: Exterior view 

of classrooms used for 

shelters at the high school 

in Canóvanas.

4.5.1.2 Culebra Ecological School, Culebra

This school (Figure 4-31) was constructed after Hurricane Georges and was designated for use as a 

shelter by PRDOH. Its identified shelter space was used during both Irma and Maria. This facility 

was also used as a medical shelter, although critical and pregnant patients were evacuated to the 

island of Puerto Rico prior to the hurricanes. Several classrooms were used as shelter areas, but the 

large gymnasium was not. 

Figure 4-31: Left, multiple rooms within the gym building was used for sheltering during both Hurricane Irma 

and Maria.
4-24 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF SCHOOLS AND SHELTERS

On September 5, before Irma’s landfall, PRDOH representatives surveyed the school and designated 

five classrooms and one room in the gym building for shelter use. One classroom was utilized for 

hospital patient sheltering. The shelter received an additional backup generator from the U.S. Army 

Corps of Engineers (USACE), as it was known to be the only community shelter on Culebra. A 

portable generator from Culebra Community Health Center was brought to the school to provide 

power for medical equipment. The original generator installed during construction for water and 

waste water was not operational during the hurricanes, although it was operational during the 

October MAT site visit. 

While the school was able to reopen two days after Hurricane Irma, it had not yet reopened after 

Hurricane Maria when the MAT visited in October. Water intrusion through jalousie windows were 

observed in designated shelter areas.

4.5.1.3 Loíza Vocational High School, Loíza 

This school (Figure 4-11), constructed in 2010, was designated a second-tier shelter and was not 

utilized during Irma or Maria. The school consists of two-story reinforced concrete-framed 

buildings, and the classrooms have been identified by PRDOH for shelter use should the school 

be activated for such purposes. During the site visits, the MAT was informed that the school has a 

generator but that it is managed by the municipality and it was not used since Maria made landfall. 

At the time of the site visit in October, the generator was not working. It had been turned on to 

provide power to the school so that the school could reopen for class but failed the first day it was 

operating. It is unclear why the generator was not used prior to that point so the facility could have 

been used as a shelter during the hurricanes. 

4.5.2 Department of Housing Shelter Program

When a storm threatens, PRDOH, PRDE, and PREMA work together to confirm the designations of 

event-specific shelters and post-event facilities; municipalities then open and operate the facilities. 

After Hurricane Maria made landfall, 257 event-specific shelters were open and in operation across 

all 78 municipalities. 

While none of these facilities were designed to meet the FEMA P-361 criteria or ICC 500 standard 

for life-safety protection, residents who chose to evacuate their homes took refuge in these facilities 

during the storm. While the best solution is to direct residents seeking shelter during storms to safe 

rooms and storm shelters specifically designed and hardened to provide life-safety protection from 

wind, wind-borne debris, flooding, and other hazards, the current program identifies available 

public buildings for use as refuge areas.

4.5.3 Considering Sheltering During School Consolidation

The Government of Puerto Rico, PRDOH, and PRDE are evaluating a number of facility programs 

after the 2017 hurricane season. One of these programs is related to the inventory of school buildings 

across Puerto Rico. The government has stated that it is considering a consolidation (PRDE 2018a) 

that would reduce the number of schools from its current total of approximately 1,100 to 855 to 

address population changes and financial challenges (PRDE 2017, PRDE 2018b). This presents an 

opportunity to consider flood, wind, and seismic vulnerabilities when choosing schools to close. 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 4-25

PERFORMANCE OF SCHOOLS AND SHELTERS

Understanding the effects that floods, hurricanes, and earthquakes can have on public school 

facilities can also help guide other decisions related to future building use. School districts can use 

these assessments to close highly vulnerable schools through consolidation, then determine what 

grant programs may be available for mitigation projects on remaining schools to reduce the impacts 

from natural hazards and allow schools to reopen sooner after major events. 

THE BEST AVAILABLE REFUGE AREA CONCEPT

The term “best available refuge area” (BARA) refers to 

an area in an existing building that has been deemed by 

a registered design professional to be likely to protect 

building occupants during an extreme-wind event better than other areas in the building when a safe room 

is not available. The BARA should be regarded as an interim measure to be used until a FEMA-compliant safe 

room or ICC-500 compliant storm shelter can be made 

available.

FEMA developed the Best Available Refuge Area (BARA) 

concept and checklist for the first edition of FEMA P-361 

to use in assessing a building’s susceptibility to damage from extreme-wind events such as tornadoes and 

hurricanes. The checklist evaluation process guides registered design professionals (architects and engineers) 

in identifying potential refuge areas at a site with one or 

more buildings.

In addition, some school facilities could 

be identified as BARAs or retrofitted 

to meet the requirements of ICC 500© 

for a storm shelter providing life-safety 

protection for residents during storms. If a 

school building can be retrofitted to meet 

ICC 500© storm shelter requirements, 

or an addition or new building can be 

constructed on an existing campus, 

it will provide a great service to the 

municipality. The municipality, PRDOH, 

and PRDE could work together to best 

judge the needs and resources of specific 

municipalities and whether a building 

is best suited as a dual-use school and 

shelter or if it could be used as a multi-use 

public building and shelter.

4.6 Residential Safe Rooms and Storm Shelters

The only residential (in-home) safe rooms observed by the MAT in Puerto Rico were identified 

on the island of Culebra; no other residential safe rooms meeting FEMA P-361 criteria were 

made known to the MAT. FEMA records indicate that five detached, residential safe rooms were 

constructed in 2004. These safe rooms were designed and constructed using funding from the 

FEMA Hazard Mitigation Grant Program (HMGP) after Hurricane Georges. 

The MAT observed no damage to any of the residential safe rooms on Culebra following Hurricanes 

Irma and Maria. However, some had been extensively modified to allow for air ventilation for 

sleeping and cooking, modifications which increased the vulnerabilities of the buildings. Although 

no damage was observed, these buildings no longer comply with FEMA P-361 and cannot perform 

the intended purpose of near-absolute life-safety protection of its occupants. Some safe rooms 

were in locations with heavy vegetation and appeared poorly maintained. In Figure 4-32, the home 

around the safe room was damaged.
4-26 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF SCHOOLS AND SHELTERS

Figure 4-32: This detached 

residential safe room 

funded through HMGP 

in Culebra was modified 

into a studio/efficiency 

apartment and no longer 

complies with FEMA P-361 

criteria. Modifications 

included additional 

openings which reduced 

the level of protection 

provided by the building.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-1

HURRICANES

IRMA AND MARIA

IN PUERTO RICO

5

MITIGATION ASSESSMENT TEAM REPORT

Performance of Hospitals, 

Public Buildings, and MidRise Buildings

This chapter provides the MAT’s observations on a variety of lowand mid-rise public buildings. Buildings in this chapter, including 

police stations, fire stations, other government buildings, and 

hospitals, are often of vital importance to communities affected by 

a disaster.

The facilities discussed in this chapter are shown in Figure 5-1. The figure includes four fire stations, 

three police stations, six public facilities, and five hospitals.
5-2 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

(

(

(

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P U E R T O R I C O

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CULEBRA

ISLA

VIEQUES

C a r i b b e a n S e a

A t l a n t i c O c e a n

Arecibo

Fajardo

Guayama

Ponce

Mayagüez

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#*3

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Fire Stations

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4

")Palmas del Mar Fire Station

#*1 Toa Baja Police Station

#*2 Corozal Police Station

#*3 Culebra Police Station

Hospitals

Culebra Community Health Center

Susana Centeno Family Health Center

Pavia Arecibo Hospital

San Juan University Pediatric Hospital

")1 Dr. Ramon Ruiz Arnau University Hospital

")2

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Public Buildings

!(6 Puerto Rico Department of Justice Building

!(5 Bayamón Municipal Building

!(4 Vega Alta Municipal Building

!(3 Culebra Municipal Building

!(2 New Toa Baja Municipal Building

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!(6

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0 20 40 10

Figure 5-1: Fire stations, police stations, other public buildings, and hospitals visited by the MAT and discussed 

Miles μ

in this report.

 5.1 Hospitals

Hospitals played a critical role while facing major challenges in response to Hurricane Maria. Even 

as businesses and other public facilities closed ahead of the storm, demand for healthcare services 

continued. Because Hurricane Maria affected nearly all of Puerto Rico, individual hospitals did not 

have the option to relocate their patients to other facilities until the storm passed. Yet, hospitals 

often suffered the same types of damage that affected other buildings. High-speed winds and 

wind-driven rain damaged hospital facilities, while prolonged power outages impeded services and 

threatened stores of medicines. Many hospitals suffered extensive physical damage that resulted in 

complete loss of function. Others worked to continue life-saving care in the face of frequent power 

outages, limited supplies, and limited usable space. The MAT visited several hospitals and healthcare 

facilities shortly after the storm to observe facility performance and assess lessons learned for future 

mitigation.

In October and December 2017, the MAT visited five hospitals in Puerto Rico to evaluate damage 

and gather information, three on the north side of the island of Puerto Rico, one on the island of 

Vieques, and one on the island of Culebra:

● Pavia Arecibo Hospital, Arecibo

● Dr. Ramon Ruiz Arnau University Hospital, Bayamón (University Hospital)
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-3

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

● San Juan University Pediatric Hospital, San Juan

● Susana Centeno Family Health Center, Vieques

● Culebra Community Health Center, Culebra

Hospitals are unique critical facilities that generally require some level of continuous operation. 

During storms, the buildings function not only to allow treatment of patients but to protect valuable 

equipment, supplies, and medicines needed during recovery. Some facilities can scale down 

operations ahead of time by cancelling elective procedures, limiting non-emergency cases, and 

sheltering patients and equipment in place. These strategies only apply to specific levels of service, 

however. Other functions, such as critical patient care, continuous treatment, and preservation of 

temperature-dependent medicines, cannot be stopped entirely without severe consequences. The 

MAT recognizes these inherent complexities and strives to best evaluate building performance, 

vulnerabilities, and damage along with related infrastructure challenges that can prevent a hospital 

from completing its mission. The MAT’s goal is to provide information on building limitations and 

vulnerabilities to hospital operators, administrators, and medical staff so that they understand how 

their operations may be impacted and can plan and execute accordingly.

5.1.1 Summary of Building Performance

Overall, the hospitals in Puerto Rico experienced high levels of roof membrane failures, building 

envelope failures, wind-driven water intrusion, rooftop equipment damage, and wind-borne debris 

failure. Much of this affected the usage of space and systems, prompting temporary closures and 

operational workarounds. Access to stable electrical power became a major challenge for most 

facilities. Infrastructure damage was widespread, and its lasting impacts became apparent in the 

weeks and months following the storm. Most hospital facilities were not outfitted with emergency 

and backup generators designed to provide power for full facility operation for extended periods 

in the order of months. As time progressed, hospitals lost main, standby, and backup power as 

equipment became stressed beyond its duty cycle. Fuel demand also became a limiting factor, with 

full demand consumption rates requiring fuel deliveries as often as every four days. Without power, 

many critical functions of the hospitals were only intermittently available. Physical damage and the 

lack of electricity also limited the use of elevators, which are essential for treatment and evacuation 

of patients who cannot walk. Such limits to mobility further hindered the efforts of hospital staff 

who may already have been limited to using some portion of a facility. 

While damage was often severe, the MAT also observed successful practices that mitigated impacts 

and assisted in recovery. The following section highlights instances when preparatory steps, 

operational planning, siting, design, and due diligence in construction helped facilities continue 

their care. The comparison of these relatively successful and unsuccessful practices can inform 

ongoing rebuilding efforts and long-term investment strategies. 

The most common impacts to hospitals were as follows:

● Water intrusion through the roof, windows and rooftop equipment

● Damage to rooftop equipment
5-4 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

● Loss of power with loss of supported equipment due to 

■ Loss of grid power

■ Failure of the hospital’s backup and emergency generators

■ Failure of externally supplied emergency generators

● Loss of vertical transportation due to

■ Water intrusion into the mechanical penthouses and controls

■ Water intrusion into the elevator cab and the cab controls

■ Damage to elevator motors and controls from power surges

5.1.2 Performance Relative to Flood

Most of the observed damage to hospitals was from wind and wind-driven rain. The hospitals were 

typically well sited outside of floodways and SFHAs shown on FIRMs. Of the four hospitals assessed 

by the MAT, none are in an SFHA according to the effective FIRM nor the Advisory Data, and none 

were impacted by coastal flooding during Irma or Maria. There were instances of poor site drainage 

at hospitals that lead to local flooding of areas of their campus, such as at Dr. Ramon Ruiz Arnau 

University Hospital, where the loading dock was inundated to a depth of 4 feet when area drains 

were overwhelmed.

5.1.2.1 Coastal Flood Impacts

None of the hospitals visited by the MAT were impacted by coastal flooding during Hurricanes Irma 

and Maria. The closest hospital to the coast, Pavia Arecibo Hospital (Figure 5-2), is 0.4 miles (0.8 

kilometers) south of the north shore of the island of Puerto Rico and 0.25 miles (0.4 kilometers) 

west of an advisory floodplain drainage basin for a portion of the Arecibo River, as noted on the 

effective FIRM (Figure 5-3). This places the hospital outside the effective and advisory flood zones 

and away from storm surge effects while giving access from major roads to the south and west. The 

hospital did not receive coastal or stream flooding from Irma or Maria.

Figure 5-2: Pavia Arecibo Hospital.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-5

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Figure 5-3: A portion of the effective 2009 FIRM showing Pavia Arecibo Hospital in Zone X, an area of minimal 

flood hazard.

5.1.2.2 Inland Flood Impacts

Dr. Ramon Ruiz Arnau University Hospital is located 6 miles (10 kilometers) south of San Juan Bay 

and is well inland (Figure 5-4). The hospital is located approximately 120 feet (37 meters) above 

sea level and is outside the effective and advisory flood zones. It did not receive coastal or stream 

flooding from Irma or Maria. 
5-6 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Figure 5-4: A portion of the effective 2009 FIRM showing Dr. Ramon Ruiz Arnau University Hospital, Bayamón, 

in Zone X.

The generator and fuel tanks for Dr. Ramon Ruiz Arnau University Hospital are behind the 

building (Figure 5-5). This area is in a depression below the surrounding grade, and storm water 

must be collected by drains and moved through storm sewer pipes to be removed from the dock 

area. During the hurricane, surface runoff overwhelmed the area’s drains (Figure 5-6) and piping 

capacity. Water flooded the loading dock to a depth of 4-5 feet (1.2-1.5 meters), reaching the bottom 

of the generator frame and fuel storage tank.

Figure 5-5: Dr. Ramon Ruiz Arnau 

University Hospital lower loading 

dock, which flooded from surface 

runoff, showing approximate high 

water level (red line), backup 

generator (red arrow), fuel tank (blue 

arrow), trailer mounted generator 

(yellow arrow), and propane tank 

(green arrow).
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-7

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Figure 5-6: The loading 

dock area at Dr. Ramon 

Ruiz Arnau University 

Hospital flooded when the 

area drains (red arrow) 

were overwhelmed by 

surface runoff.

San Juan University Pediatric Hospital (Figure 5-7 and Figure 5-8) is located well inland, 3 miles 

(4.8 kilometers) southeast of San Juan Bay and 4 miles (6.4 kilometers) south of the island’s north 

shore. This places the hospital outside the effective and advisory flood zones, and it did not receive 

coastal or stream flooding from Irma or Maria. The hospital is approximately 80 feet (24 meters) 

above sea level. 

Figure 5-7: Location of San Juan University Pediatric Hospital in Zone X, an area of minimal flood hazard, on the 

effective FIRM.
5-8 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Figure 5-8: View of the 

front entrance of the San 

Juan University Pediatric 

Hospital.

Susana Centeno Family Health Center is roughly in the center of the island of Vieques, in an X Zone 

(Figure 5-9). This places the hospital outside the effective and advisory flood zones, and it did not 

receive coastal or stream flooding from Irma or Maria. 

Figure 5-9: A portion of the effective 2009 FIRM showing Susana Centeno Family Health Center in an X Zone.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-9

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

5.1.3 Performance Relative to Wind

Building performance in high winds depends on the performance of the MWFRS and the building 

envelope, the latter including openings and the roof covering.

5.1.3.1 Main Wind Force Resisting System 

The main structural systems of hospitals performed well during the hurricanes with no observed 

damage or failures of elements of the MWFRS. Based on the visual assessments conducted by the 

MAT in October and December 2017, there was no structural damage to the roof decks or any 

structural elements from the wind events.

5.1.3.2 Openings

Building openings suffered in varying degrees from modest to severe damage. Nearly all the 

hospitals had some window damage, with San Juan University Pediatric Hospital and Culebra 

Municipal Health Center having the least. Pavia Arecibo Hospital had several windows breached 

and blown in, Dr. Ramon Ruiz Arnau University Hospital had an entire row of windows pulled out 

of the building, and the Susana Centeno Family Health Center had substantial water enter through 

windows and roof leaks (Figure 5-10). 

Figure 5-10: Susana 

Centeno Family Health 

Centers in Vieques.

Pavia Arecibo Hospital has a tower section to the north and a low-rise section to the south. The tower 

section saw window damage from pressure on the sixth floor. Combined with roof covering damage, 

this led to water intrusion that damaged sections of the drop ceilings on the fourth and sixth 

floors. In the fourth-floor intensive care unit, a portion of the drop ceiling collapsed, a window was 

breached, and glass doors that served the helipad were blown out. Some of the first-floor windows 

and shutters were damaged. Some windows had no glazing protection (Figure 5-11). The first-floor 

medical records department lost entire windows when wind pressure forced glazing out of window 

frames and the window frames out of their rough openings in the wall (Figure 5-12). Wind-driven 

rain entered the mechanical penthouse through ventilation louvers; this water intrusion caused the 

elevators to fail. 
5-10 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Figure 5-11: This view of Pavia Arecibo Hospital 

shows that some windows had glazing protection 

(red arrow) while others did not (green arrows).

Figure 5-12: At Pavia Arecibo Hospital, a window 

frame was pulled out of the building (green circle). 

The frame was inadequately anchored to the wall 

opening.

Figure 5-13: Rain water 

from the fourth floor of 

Dr. Ramon Ruiz Arnau 

University Hospital, 

Bayamón, migrated to 

the lower floor through 

floor penetrations and 

inundated numerous 

systems including 

electrical conduits and 

communications boxes 

(green arrow).
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-11

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Figure 5-14: Water infiltrated the floors below and was 

captured to minimize further damage at Dr. Ramon Ruiz 

Arnau University Hospital.

Dr. Ramon Ruiz Arnau University Hospital had numerous wind failures during the storm, 

introducing wind and wind-driven rain into the building. While the fourth floor was out of service 

at the time of the storm, water that reached the fourth floor was able to leak into the operational 

third floor through floor penetrations (Figure 5-13 and Figure 5-14). Rainwater entered the hospital 

through gaps around the window frames and through poor window-to-frame connections which 

led to entire window frames being pulled out of the wall (Figure 5-15 and Figure 5-16). Only two 

fasteners could be seen restraining the missing 25-foot (7.6-meter) section of a lower window frame 

(Figure 5-17).

Figure 5-15: View of central 

section of Dr. Ramon Ruiz 

Arnau University Hospital 

showing broken windows 

as well as entire window 

and frame missing from 

wall (red circle).
5-12 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Figure 5-16: A 25-foot (7.6-meter) section of 

window and frame are missing from the fourthfloor wall of Dr. Ramon Ruiz Arnau University 

Hospital (red arrow).

Figure 5-17: Only two fasteners were observable 

restraining the lower section of the missing 25-foot 

(7.6-meter) section of window system at Dr. Ramon 

Ruiz Arnau University Hospital (red arrows).
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-13

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

At San Juan University Pediatric Hospital, debris impacts broke several windows, and several others 

leaked. None of the windows have storm shutters. It is not known if the windows are impact-rated. 

The windows flexed and moved, breaking the seals with the frames and walls and allowing winddriven rain to enter the building. The building’s stucco coat was also compromised, allowing water 

to enter the envelope through cracks and spalls. Broken stucco also became debris for lower floors.

The Susana Centeno Family Health Center did not appear to experience structural failures in the 

walls or roof deck. However, there was significant water intrusion through windows and through 

the roof deck after the built-up roof covering was damaged and punctured by wind-borne debris. 

While all glazed windows and doors had window shutters installed, several windows and doors were 

damaged or broken because of improper deployment of the shutter systems.

The exterior walls of the Susana Centeno Family Health Center appeared to weather the storms 

with minimal damage from wind pressure and debris impact. The windows and doors of the facility 

had variable performance: Most were not broken or damaged, as all glazed windows and most 

glazed doors were protected by accordion shutter systems. However, there were problems with the 

installation and maintenance of the shutter systems. Figure 5-18 illustrates several problems related 

to the deployment and maintenance of storm shutter systems. Note also the metal panel jalousie 

window in the center of the wall that is not protected against water intrusion or debris impact. 

Proper maintenance and operations procedures, including periodic shutter deployment exercises, 

could have proactively identified these problems that prevented full deployment of the building’s 

shutters. 

Figure 5-18: Successes 

and problems related to 

installation of shutter 

systems over glazed doors 

and windows, including a 

shutter system properly 

installed (green arrow), 

a shutter system with a 

track missing at a glazed 

door (red arrow), a window 

air conditioning unit 

preventing a shutter being 

deployed (orange arrow), 

and a pair of glazed doors 

without glazing protection 

(yellow arrow). 
5-14 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

The windows and doors around the facility allowed entry of wind-driven rain, which wetted the 

interior of the building. This wetting combined with a loss of power after the hurricanes resulted in 

mold and poor air quality throughout the facility. 

5.1.3.3 Roof Coverings

Failures of roof coverings and resulting water 

intrusion were primary causes of severe 

damage and loss from the hurricanes. The 

MAT encountered membrane roof systems as 

well as single-ply and modified bitumen roof 

membranes. Performance of the roof coverings 

was typically poor, with some hospitals 

experiencing near complete blow-off, while 

other experienced multiple punctures. 

The roof covering at San Juan Pediatric Hospital 

had minor damage and was essentially intact 

but developed leaks during the extended period 

of heavy rainfall and high winds. 

Pavia Arecibo Hospital suffered roof damage 

that caused interior ceilings to collapse. Damage 

included lost roof sealant/membranes, roof and 

window damage on the sixth floor, and damage 

to sections of drop ceilings on the fourth and 

sixth floors. In the fourth-floor intensive care unit, a portion of the drop ceiling collapsed, and a 

window was breached from wind pressure. Also, one HVAC unit was displaced by the high winds 

partially as a result of salt spray and corrosion damage. 

Dr. Ramon Ruiz Arnau University Hospital performed well structurally, but the building envelope 

suffered substantial breaches, including roof breaches. The membrane covering the central section 

peeled off, exposing most of the cap sheet and allowing water to infiltrate the floors below (Figure 

5-19). The single-ply membrane tore free from its mechanical fasteners (Figure 5-20). At the time 

of the MAT visit in October, the hospital was waiting for emergency roof coverings to be deployed. 

DESIGNING SAFER HOSPITALS

FEMA 577 Design Guide for Improving Hospital 

Safety in Earthquakes, Floods, and High Winds: 

Providing Protection to People and Buildings 

(FEMA 2007) has information on the variety of 

vulnerabilities faced by hospitals exposed to 

earthquakes, flooding, and high-winds risks, as well 

as the best ways to mitigate the risk of damage and 

disruption of hospital operations caused by these 

events. Although not a comprehensive mitigation 

design manual, it introduces the fundamental 

principles of natural hazard risk reduction, with 

an emphasis on mitigation planning and the 

design of hospital buildings. The guide is available 

at https://www.fema.gov/media-library/assets/

documents/10672

Figure 5-19: The roof membrane over the 

central section of Dr. Ramon Ruiz Arnau 

University Hospital peeled off over most of 

the roof, allowing water intrusion into the 

floors below.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-15

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Figure 5-20: The roof 

membrane at Dr. Ramon 

Ruiz Arnau University 

Hospital tore free from its 

mechanical fasteners.

The Susana Centeno Family Health Center’s roof covering appeared to be the original roof coverings 

installed during construction. The roof covering stayed in place but developed leaks from a number 

of punctures across the roof likely caused by debris. Some of the debris may have come from failure 

of a solar array on the east corner of the roof (section 6.2.3.1). However, much of the debris was likely 

generated from homes on the hillside above the facility that were damaged during the storm. While 

the roof covering did not peel away, it was punctured and damaged. The built-up roof materials 

had large impact holes through the roof cover and the supporting insulation. This resulted in the 

insulation becoming exposed and saturated by the rain from the event. Figure 5-21 shows one of the 

larger holes in the roof covering caused by wind-borne debris. The hospital staff stated there were 

multiple roof leaks (with additional water infiltration through the windows and doors), but no tarps 

or patches were observed covering the holes in the roof during the December site visit (Figure 5-22). 

Rapidly repairing this type of damage is vital for disaster recovery and preventing further damage.

Figure 5-21: Roof covering puncture at 

Susana Centeno Family Health Center.
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PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Figure 5-22: View across 

the roof of Susana Centeno 

Family Health Center, 

looking south.

Culebra Community Health Center had two wings, each with a metal gable roof. The roof of the 

surgery wing experienced some water intrusion (Figure 5-23).

Figure 5-23: Interior of the 

Culebra Community Health 

Center, which experienced 

water intrusion through 

the roof.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-17

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

5.1.3.4 Rooftop Equipment 

Rooftop equipment was commonly damaged by the high winds, frequently when it was tipped over or 

otherwise displaced. Connectors that secured equipment were often broken. Some connectors had 

been weakened by corrosion. Using more and larger fasteners and connectors, and using fasteners 

and connectors made from corrosion-resistant materials, can reduce this kind of damage. Greater 

numbers of fasteners will assure redundancy, while larger fasteners will provide more sacrificial 

material as the elements are consumed by the environment. Using corrosion-resistant materials such 

as stainless steel, brass, or silicon bronze will slow the rate of corrosion, though they will not stop it.

Pavia Arecibo Hospital is relatively close to the coast (0.4 miles [0.6 kilometers]) and had considerable 

corrosion of rooftop equipment and connectors. Proximity to the coast exposes the hospital to 

salt spray. The aggressive environmental effects had pronounced impacts on rooftop structures 

including vents, frames, and rooftop mounted air conditioning units (Figure 5-25). Several pieces of 

rooftop mechanical vents and equipment were blown off their mountings during the storm (Figure 

5-24 and Figure 5-25), including two 7.5-ton-capacity vents and one 5-ton-capacity HVAC unit 

with two complete condensers. The connections to their mounts were inadequate and weakened 

by corrosion. These fasteners and connections failed after being overstressed. The rooftop HVAC 

serving the lower section was also damaged, as were rooftop vents. Lightning protection systems and 

antennas found on the roof appeared to be undamaged from the winds.

Figure 5-24: Damage to 

rooftop HVAC equipment 

at Pavia Hospital Arecibo.
5-18 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Figure 5-25: Damaged 

rooftop HVAC unit at Pavia 

Arecibo Hospital showing 

extensive corrosion. The 

unit is upside down and is 

missing side panels. The 

anchorage points on the 

bottom (now facing up) are 

rusted through and torn 

out.

The Pavia Arecibo Hospital signage was also blown off (Figure 5-26). The sign backing and armature 

were not able to withstand the forces generated by the high winds. Roof vent coverings were 

damaged or lost, and the roof covering was damaged. All building components must be designed 

for the forces presented by high winds, including appurtenances and signs. 

Figure 5-26: Loss of signage 

at Pavia Hospital Arecibo. 

The sign frame or armature 

was inadequately attached 

to the parapet, and the 

fasteners failed.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-19

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Dr. Ramon Ruiz Arnau University Hospital had damage to rooftop equipment as well as roof 

coverings. Exhaust fans on the central tower section of the hospital were moved off their mounting 

pads and frames under the hurricane-force winds (Figure 5-27). The damage rendered them 

inoperable and exposed the floors below to rainwater. These fans did not have sufficient connectors 

to hold them in place. Design of these connectors requires special attention, because the fans must 

be placed on vibration isolation mountings. The connectors must be flexible and must provide 

adequate strength in compression and in uplift. Additional straps or cables could be used to account 

for the vibration isolation mounts.

Figure 5-27: Rooftop 

fan at Dr. Ramon Ruiz 

Arnau University Hospital 

displaced from support 

frame by hurricane winds. 

Vibration isolation mounts 

can be seen in the corners 

(red arrows) and part of 

another next to the frame 

(green arrow).

Much of the rooftop equipment at San Juan University Pediatric Hospital was protected behind 

parapets on lower levels, but some rooftop equipment was blown over. Figure 5-28 shows a fan that 

was turned over at the top of one of the towers, while Figure 5-29 shows a rooftop fan cowling 

blown off, exposing the floors below to water infiltration from rainfall. The screws that attached the 

upper cowling pulled through the sheet-metal. Additional screws could have been used to provide 

more resistance to the wind loads and stainless-steel cables could have been added as is a common 

practice in high wind areas. Both of these fans lacked secondary straps to secure them in their 

original positions. There were cases where the ductwork insulation was blown off, allowing water to 

enter the ductwork and flow into the building. 

Figure 5-28: Rooftop equipment located 

on top of one of University Hospital 

towers that was blown over.
5-20 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Figure 5-29: A rooftop fan damaged 

by winds at Dr. Ramon Ruiz Arnau 

University Hospital.

There was not a large amount of rooftop equipment at the Susana Centeno Family Health Center. 

Some small air-handling units and vent hoods were damaged and displaced (Figure 5-30), although 

most vent hoods remained in place without damage. The largest equipment feature on the roof was 

the solar array on the east side of the roof (Figure 5-31). A number of panels were missing from this 

array, particularly from the two rows nearest the edge of the roof, apparently having been removed 

by wind forces. Several of the remaining panels had been damaged by wind-borne debris impacts 

(Figure 5-32). 

Figure 5-30: Small air 

handling units displaced 

and off their stands on top 

of the roof. Note displaced 

electrical conduit in 

background of photo (red 

arrow).
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-21

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Figure 5-31: Rooftop 

solar array at east corner 

of hospital roof. The 

blue arrow indicates the 

direction of the strongest 

winds based on debris 

fields observed around the 

hospital.

Figure 5-32: Rooftop solar 

array at east corner of 

hospital roof showing 

damage from windborne debris impacts (red 

circles).
5-22 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

5.1.4 Impacts to Operations

The most important operational challenges to hospitals from Hurricanes Irma and Maria were 

related to the loss of emergency and backup power and the loss of conveyances.

5.1.4.1 Emergency Power and Backup Power

Hospitals use electrical power for many vital functions: maintaining indoor air quality and 

temperatures, powering medical equipment, cooling medicines and supplies, preparing and storing 

food, providing lighting and communications, running cleaning and sanitation equipment, and 

providing mobility and vertical transportation. Loss of power in a hospital renders it out of service 

and requires patients to be moved to other locations.

Pavia Arecibo Hospital lost grid power and was reliant on backup and emergency power generation. 

The hospital’s own emergency generators also failed, and additional generators were supplied by 

FEMA. The hospital has two FEMA-supported generators in addition to the existing emergency 

generator for emergency circuits and lights (Figure 5-33). The hospital has two substations that 

provide 2.5 megawatts (MW) and 1 MW, respectively, and a single 1 MW generator. At the time of 

the site visit in October 2017, only one of the two FEMA generators was working.

Figure 5-33: Hospital 

Generator (blue arrow) 

and two FEMA-Supplied 

Generators (yellow 

arrows) at Pavia Hospital 

Arecibo.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-23

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

The loss of power created cascading losses of function. The hospital towers are dependent on 

vertical transportation to provide access and move patients and supplies. The loss of power also left 

HVAC inoperable, allowing air temperatures to rise and rendering some spaces unusable. 

Dr. Ramon Ruiz Arnau University Hospital lost grid power during the hurricane and ran on their 

own backup generator. This generator failed after 13 hours, possibly due to water intrusion into the 

wiring. Small portable generators were used to provide some lighting and critical services for the 

emergency room. Power from the city was restored after 11/2 weeks; however, it remained unreliable 

and intermittent. Five days later, the generator was brought back into service, and a trailer-mounted 

emergency generator was delivered but not connected. With the hospital running on generatorsupplied power, only 30 percent of hospital functions were supported, including the emergency 

department, intensive care unit, and parts of other departments. The hospital does not have a 

full-building uninterruptible power supply, and when power from the city is disrupted, there is a 

10-to-15-second period during which all systems go offline before the backup generator restores 

power.

The hospital’s generator and fuel tanks are at the back of the building (Figure 5-5). After surface 

runoff overwhelmed the area’s drains and piping capacity, water flooded the loading dock to a depth 

of 4-5 feet (1.2-1.5 meters), reaching the bottom of the generator frame and fuel storage tank in the 

loading dock area. This location places the generator and fuel tank in a location that cannot be 

served in flood events. Should the area drains fail completely, access could be lost for weeks. These 

mission-critical elements should be relocated to high ground not subject to flooding and with access 

in severe conditions. Prolonged loss of backup systems will further reduce the hospital’s ability to 

function. The new location for the relocated gear does not necessarily need to be adjacent to the 

building and can be located several hundred feet away, also reducing emissions and noise in the 

hospital. Standardized emergency connections should also be considered so that trailer mounted 

generators can be quickly put into service when necessary.

Figure 5-34: View of one 

of the standby generators 

(red arrow), two of the 

backup generators (green 

arrows), and a fuel tank 

(blue arrow) at San Juan 

University Pediatric 

Hospital.
5-24 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

San Juan University Pediatric Hospital has four generators that can provide 100 percent of the 

hospital’s power requirements (Figure 5-34). Tower One has a 1,700 kilowatt (kW) standby generator, 

and Tower Two has a 1,250 kW standby generator. There are two 750 kW backup generators for the 

towers as well (Figure 5-35).

The backup generators were not working at the time of the MAT visit; however, this was not directly 

due to hurricane damage but to protection systems and warning lights that required maintenance 

and repairs. 

The hospital had been functioning on generator power for weeks at the time of the visit, and fuel 

demand was a concern. Tower One’s generator can run for five days on a full tank, while Tower 

Two’s can run for seven days. This means that a fuel delivery (Figure 5-35) is required twice a 

week. FEMA was instrumental in coordinating fuel deliveries to keep the hospital functioning. The 

frequent deliveries required access to a fuel delivery point co-located with a main entrance. The fuel 

truck is on the sidewalk under the porte-cochere within inches of the roof. The delivery location 

lacked spill controls, fire controls, traffic controls, separation from pedestrian traffic, exhaust and 

fume management, and storm water management measures. Facilities that rely on fuel deliveries 

to maintain operations, especially as a regular occurrence, should have well designed access and 

delivery points that provide for safe and efficient use.

Power to Vieques and the Susana Centeno Family Health Center was provided by an underwater 

cable from the main island prior to Hurricanes Irma and Maria. Hospital staff attempted to provide 

emergency services during the hurricanes. After the cable was damaged during Hurricane Irma, 

the hospital was able to operate on generator power for two weeks. Shortly after external power was 

restored, Hurricane Maria damaged the underwater cable again, forcing the hospital to return to 

generator power. After two weeks, the generator failed, and the facility was without power. 

Figure 5-35: View of fuel 

truck refilling the fuel tank 

for University Hospital 

Tower One. Note the tight 

clearance between the 

porte-cochere ceiling and 

the top of the tanker truck 

(red arrow.)
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-25

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

By the time of the December 2017 MAT observations, the facility was able to partially operate on a 

250 kilovolt-ampere Tesla solar and battery power system operating in the parking lot of the hospital. 

Power was available to provide lighting and some air handling to the approximately six medical tents 

at the site and some of the hospital building. However, the building was not fully functional on the 

limited power supplied by the solar power system. While there were secondary emergency generators 

on site, they did not function. (The MAT was unable to determine the backup power generator size 

or fuel tank capacity.) Although the hospital stores water on site in a 50,000-gallon (189,000-liter) 

cistern, the water could not be used because of insufficient power for the water pumps. Due to the 

lack of available water, the poor air quality, and the possible presence of mold, the Government of 

Puerto Rico has determined it must close. 

At Culebra Community Health Center (Figure 5-36), patients able to evacuate were moved to the 

island of Puerto Rico prior to the hurricanes. Those unable to evacuate were brought to a school 

designated for use as a shelter, as discussed in chapter 4. One of the hospital’s two wings was 

functional at the time of the MAT visit, but the other, the surgery wing, was not functional due to 

water intrusion through the roof that had resulted in hazardous conditions. A securely strapped 

HVAC unit (Figure 5-37) is an example of successful mitigation that helped the facility continue in 

partial operation after the hurricanes.

Figure 5-36: Culebra 

Community Health Center 

functioned on generator 

power after Hurricanes 

Irma and Maria. Source: 

Hector Huyke Villeneuve / 

FEMA, December 9, 2017 

https://www.fema.gov/

media-library/assets/

images/154945
5-26 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Figure 5-37: This HVAC unit at the Culebra 

Community Health Center is strapped to 

a concrete platform; however, it rests on 

plastic supports that are not mechanically 

anchored.

5.1.4.2 Conveyances

Vertical transportation is a critical element to a hospital’s function as staff, patients, supplies, and 

equipment are constantly moving within the facilities. One hospital noted that loss of their elevators 

was the single biggest problem they faced after Hurricanes Irma and Maria.

The elevators at Pavia Arecibo Hospital were rendered inoperable for days after the storms due 

to water infiltration through the roof and mechanical penthouse. This water then entered the 

elevator shafts, eliminating most of the vertical transportation. While the main logic controls were 

not damaged, the water damaged the elevator cab controls in the service elevator and 2 personnel 

elevators. The elevators were repaired after five days, but the absence of vertical transportation 

meant that extraordinary efforts were required to maintain functioning of the hospital for the 

following week. Three times a day, a human chain was used to move food, supplies, fresh linens, and 

other materials up into the upper floors and also to move waste and soiled linens down and out of 

the tower. 

The vertical conveyance system at Dr. Ramon Ruiz Arnau University Hospital suffered significant 

damage and loss of function from the hurricanes. Only two of the five elevators remained in 

service during and after the hurricanes. The mechanical penthouse that protected the motors 

and controls was inundated by wind-driven rain (Figure 5-38), which entered through ventilation 

louvers required to provide air movement and maintain acceptable operating temperatures during 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-27

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

normal conditions. These ventilation openings allowed water to spray the gear and controls during 

the hurricane (Figure 5-39). The motors and gear are robust and were minimally affected, but the 

control cabinets and controls were damaged, and the elevators served by these damaged controls 

went out of service (Figure 5-40). No injuries were reported as a direct result of the elevator failures. 

Figure 5-38: Elevator mechanical 

penthouse enclosing the elevator 

gear at Dr. Ramon Ruiz Arnau 

University Hospital. Note ventilation 

louvers on the sides where rain 

entered.

Figure 5-39: Elevator controls that 

were inundated with wind-driven 

rain and failed during the hurricane 

at Dr. Ramon Ruiz Arnau University 

Hospital.

Figure 5-40: Elevator gear and 

controls located in the elevator 

penthouse at Dr. Ramon Ruiz Arnau 

University Hospital.
5-28 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Hurricanes Irma and Maria left eight of the twelve elevators at San Juan University Pediatric 

Hospital’s two towers out of service, nearly eliminating hospital function and greatly affecting 

mobility. Hospital staff stated that lack of vertical conveyance was the most difficult issue to manage. 

Two elevator machine rooms and four elevators were damaged by power surges, which also started 

fires at the controls. Smoke from these fires escaped back into the building and temporarily caused 

poor air quality.

5.2 Police and Fire Stations

The MAT assessed several fire and police stations. The facilities observed were built with reinforced 

concrete and did not suffer any structural damage. The Toa Baja Fire Station could be considered 

a structural success, because it suffered only minor damage due to its elevated floor and metal 

shutters; however, not all facilities performed as well. The Corozal Police Station was inundated by 

more than six feet (1.8 meters) of water, damaging the generator and other building contents. The 

Palmas del Mar Fire Station suffered wind damage to several windows, mostly from wind-borne 

debris.

5.2.1 Performance Relative to Flood

This section summarizes the performance of police and fire stations exposed to coastal and inland 

(riverine) flooding. Most of these facilities observed by the MAT were not in SFHAs and did not 

flood. However, some riverine flooding was observed.

5.2.1.1 Coastal Flood Impacts

The Culebra Police Station and the Luquillo Fire Station are located along the coast of Puerto Rico 

and are outside of the Advisory SFHA (Figure 5-41 and Figure 5-42). The MAT assessment did not 

identify any signs of coastal inundation. However, the proximity to the coastline provides little cover 

and leaves the facilities exposed to unobstructed high winds. 

5.2.1.2 Inland Flood and Rainfall Impacts

The Corozal Police Station, in the central-eastern region of Puerto Rico, was inundated with more 

than 6 feet (1.8 meters) of water. The effective FIRM showed the facility to be just outside the SFHA 

(Figure 5-43, top); however, the Advisory Data shows the facility inside the SFHA (Figure 5-43, 

bottom). 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-29

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Figure 5-41: Location of the Culebra Police Station on the effective 2009 FIRM. The facility was not damaged 

by coastal inundation.

Figure 5-42: Location of the Luquillo Fire Station on the effective 2009 FIRM. The facility was not damaged 

by coastal inundation.
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PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Figure 5-43: Corozal Police Station, top, shown on the effective 2009 FIRM; bottom, shown on the Advisory 

Data.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-31

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Floodwaters from the adjacent Rio Corozal inundated the ground floor of the Corozal Police 

Station (Figure 5-44, left), inundating the power generator (Figure 5-44, center) and damaging 

other building contents. The MAT was unable to determine the first-floor elevation of the facility1. 

However, the second story did not suffer any visible flood damage and was operated by a portable 

generator (Figure 5-44, right) during the MAT assessment. Placing the generator on the second floor 

would have avoided inundation of the generator and reduced the facility’s operational downtime.

Figure 5-44: Corozal Police Station, left, overview; center, damaged backup generator; right, portable 

generator used after Hurricane Maria. Yellow line indicates high water mark.

The municipality of Toa Baja, located on the north coast of the island, was one of the areas most 

impacted by riverine flooding. The Toa Baja Police Station is located inside the 100-year floodplain 

(Figure 5-45) and was inundated with 4-5 feet (1.2-1.5 meters) of water. The facility’s staff moved 

most of the computer systems and files to the second floor; however, some operational aspects were 

compromised due to the first-floor flooding. Tile and concrete walls helped reduce damage; however, 

electrical (Figure 5-46) and plumbing damage was observed. The Municipality is considering 

relocating the facility to a location outside of the SFHA.

The Toa Baja Fire Station sits across the street from the Toa Baja Police Station (Figure 5-46). The 

facility is located inside the 100-year floodplain, less than 300 feet (91 meters) from the floodway of 

the Rio La Plata; however, it suffered little or no structural damage from flooding. To protect against 

flooding, essential components of the facility including communications, firefighting equipment, 

and the generator are elevated above the design flood elevation (Figure 5-47). In the case of a flood 

event, the fire trucks are relocated to a higher elevation to avoid any inundation damage. Metal 

shutters protected the facility’s doors and windows from wind-borne debris.

1 The 500-year-flood elevation given on the effective FIRM is 258.5 feet (78.5 meters) above mean sea level. 
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Figure 5-45: A portion of the effective 2009 FIRM showing the Toa Baja Police Station.

Figure 5-46: Toa Baja Police Station (left), damaged files and office equipment (center), electrical damage (red 

circle-right). Yellow line indicates high water mark.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-33

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Figure 5-47: Left, approximate flood elevation and power generator (red circle) in the background; right, steps 

to the first floor (right) of the Toa Baja Fire Station.

5.2.2 Performance Relative to Wind

All the police and fire stations observed by the MAT were built with reinforced concrete. All 

performed well in the hurricanes’ high winds, with none showing signs of structural damage.

5.2.2.1 Openings

At the Culebra Police Station, jalousie windows allowed water intrusion caused by wind-driven rain. 

However, the MAT observed several cases in which properly installed shutters provided sufficient 

protection to openings on fire and police stations. The Toa Baja Fire Station had security grilles in 

the truck bays (Figure 5-48, left) and metal window shutters (Figures 5-48, right) that successfully 

protected the facility from wind debris impacts.

Figure 5-48: Toa Baja Fire Station. Left, security grills (red arrows) protected equipment from wind-borne 

debris. Right, metal shutters (blue arrows) protected the building from wind-borne debris.
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PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Florida Fire Station and Luquillo Fire Station had storm shutters that successfully protected their 

windows from impact, though the MAT observed wind-borne debris nearby, (Figure 5-49). However, 

Luquillo Fire Station suffered minor damage from water intrusion through its jalousie windows.

Figure 5-49: Metal shutters 

installed at the Luquillo 

Fire Station successfully 

protected the facility’s 

openings.

Figure 5-50: Metal shutters installed at the Florida Fire Station successfully protected the facility’s openings.

The shutter systems installed on the Palmas del Mar Fire Station performed well when properly 

deployed. However, some shutters were not in place at the time of the event, resulting in window 

damage caused by wind-borne debris (Figure 5-51). The damage may be attributed to storage issues 

and lack of a maintenance and installation plan. The metal shutters deployed on this facility are 

commonly used in the region due to their moderate cost and easy installation. However, they must 

be installed and taken down for every event. This creates a need for storage space and requires 

additional planning by the facility manager. 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-35

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Figure 5-51: The Palmas del Mar community requires decorative tile roofs. The Palmas del Mar Fire 

Station included decorative tile roof coverings over portion of the building (red circles). The tiles were not 

mechanically attached, and some failed, contributing to wind-borne debris.

Figure 5-52 illustrates tiles lost from the facility’s roof covering, which contributed to wind-borne 

debris. 

Figure 5-52: Damage to tile roof (red oval) covering at the Palmas del Mar Fire Station. Red arrows 

indicate broken tiles.
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PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

5.2.2.2 Roof System

The Culebra Police Station suffered water damage from water intrusion through the roof and 

windows. There were visible ponding and signs of poor maintenance on the roof at the time of 

assessment (Figure 5-53). 

Figure 5-53: Ponding and roof damage (red arrows) at the Culebra Police Station.

The air conditioning unit (Figure 5-54, left) of the Luquillo Fire Station was successfully strapped in 

place. However, the practices recommended in Puerto Rico Recovery Advisory 1, Rooftop Equipment 

Maintenance and Attachment in High-Wind Regions (FEMA PR-RA1, Appendix D) would require 

one additional mechanical attachment. The cooling fan (Figure 5-54, center) came loose due to 

the strong winds. The facility suffered minor damage from water intrusion through the roof and 

windows. There were visible signs of poor maintenance on the roof at the time of assessment (Figure 

5-54, right). 

Figure 5-54: Rooftop equipment at the Luquillo Fire Station, including, left, air conditioning unit; center, 

cooling fan; right, rooftop damage.

The Florida Fire Station suffered minor roof damage due to ponding and maintenance issues 

(Figure 5-55, left). The facility’s grade-mounted AC condensers were successfully strapped and did 

not tip over (Figure 5-55, right).
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-37

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Figure 5-55: Florida Fire Station, with, left, minor roof damage, right, strapped AC condensers.

SAN JUAN EMERGENCY OPERATIONS CENTER 

The San Juan Emergency Operations Center (EOC) (Figure 5 56) is an underground facility originally built in the 

1970s and renovated in the early 2000s after the attacks of September 11, 2001. The facility was operational 

during Hurricanes Irma and Maria and was running with backup power at the time of the MAT visit. Backup 

power consisted of twin diesel generators operated alternately so that one provided power while the other 

was maintained. The EOC operated on backup power for several months until grid power was restored. The San 

Juan EOC complex hosts a 911 emergency call center, which also remained operational during both hurricanes. 

The complex did not show signs of flood or wind damage.

Figure 5-56: San Juan EOC, left, exterior, right, interior.
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PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

5.2.3 Impacts to Operations

Hardening the Toa Baja Fire Station with metal shutters and elevating or relocating the essential 

components successfully protected the building and its components. However, the facility was 

not operational for more than a month after the event due to generator failure. The facility’s 

generator was elevated (Figure 5-57, left) but was not operational at the time of the MAT visit 

due to a mechanical problem; however, when it was in use, its location allowed fumes to enter the 

sleeping quarters. To address this problem, a temporary piping system had been installed to convey 

smoke away from the building. This solution could reduce the efficiency of the generator. A second 

generator had been provided (Figure 5-57, right) but had no fuel at the time of the MAT visit. 

At Luquillo Fire Station, the emergency generator was not functioning at the time of the MAT 

assessment. At both fire stations, the lack of a proper operations and maintenance plan prevented 

the facility from being a complete success story.

Figure 5-57: Toa Baja Fire Station. Left, generator (red circle) with temporary piping system (red arrow) 

installed to convey generator smoke away from the building. Right, portable generator supplied after 

Hurricane Maria.

5.3 Mid-Rise Buildings

Mid-rise buildings are buildings having from five to approximately 10 floors. Due to their height, 

they require the use of elevators. The MAT assessed several mid-rise buildings, all of which had 

governmental functions. Typical uses of mid-rise buildings in Puerto Rico are apartments, hotels, 

condominiums, health care and office buildings. 

5.3.1 Summary of Building Performance

Mid-rise buildings require professional design due to their complexity and technical challenges. 

Mid-rise buildings typically had reinforced concrete cores and did not suffer structural damage 

from wind. The facilities were all sited well and remained above or outside areas of flooding. 

However, the MAT observed considerable damage to and loss from these buildings due to breaches 

and failures that admitted wind and wind-driven rain. 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-39

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

5.3.2 Performance Relative to Flood

No mid-rise facilities investigated by the MAT were inundated by coastal or riverine flooding from 

Irma or Maria, although some are located in the SFHA and are vulnerable to future flooding. Some 

of these successes are the result of buildings having been relocated to areas of lower flood risk after 

previous disasters.

5.3.2.1 Coastal Flood Impacts

The Department of Justice of Puerto Rico (PRDOJ; Departamento de Justicia de Puerto Rico) 

occupies a building in San Juan 0.5 miles (0.8 kilometers) south of the north shore and less than 

0.25 miles (0.4 kilometers) from San Juan Bay (Figure 5-58). The PRDOJ building is approximately 

20 feet (6.1 meters) above sea level and is outside the effective and advisory flood zones (Figure 

5-59); it did not receive coastal or riverine flooding from Irma or Maria. 

Figure 5-58: View of the 

northeast corner of the 

PRDOJ building in San 

Juan after hurricane 

Maria. 
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PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Figure 5-59: A portion of the effective 2009 FIRM showing the PRDOJ building in the X Zone.

Toa Baja is a low-lying community near the north shore of Puerto Rico 8 miles west of San Juan. 

The Toa Baja Municipal Building was previously located in an area prone to flooding from Rio de 

la Plata, the longest river in Puerto Rico, and was approximately 2 miles (3 kilometers) south of the 

north shore. When a larger building was needed, a new one was built 2 miles away, approximately 

2.5 miles (4 kilometers) from the ocean and 2 miles (3 kilometers) from the Rio de la Plata, elevated 

on fill. The new building was inaugurated in 1996. With this choice of location (Figure 5-60) and 

building elevation, the building did not flood during the hurricanes. However, the building is still 

partially in the SFHA, and an underground parking structure (Figure 5-61), due to its low elevation, 

is at risk of inundation during flood events less severe than the base flood. 

Culebra City Hall is located in the Culebra Municipal Building. The building is within 100 feet (30 

meters) of the shore but was located well and did not experience coastal flooding. However, the 

failure of a sump pump allowed surface water to flood a portion of the building. The building is 

located at the boundary of the SFHA on the FIRM (Figure 5-62).
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-41

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Figure 5-60: Toa Baja Municipal Building showing 

relief from surrounding terrain by use of elevation 

on fill. Stairs lead to the building’s elevated pad (red 

arrow).

Figure 5-61: Toa Baja Municipal Building showing 

relief from surrounding terrain and entrance to 

underground parking (red arrow).

Figure 5-62: A portion of the effective 2009 FIRM showing the Culebra Municipal Building. The facility is 

partially in the SFHA but was not damaged by coastal inundation.
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PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

5.3.2.2 Inland Flood Impacts

The Vega Alta Municipal Building (Figure 5-63) is located 15 miles west of San Juan and well over 4 

miles (7 kilometers) inland of the north shore. It did not flood. The building is located outside the 

SFHA on the FIRM (Figure 5-64).

Figure 5-63: Northwest view of Vega Alta 

Municipal Building. The building is located 

outside the SFHA and did not flood.

Figure 5-64: A portion of the effective 2009 FIRM showing the Vega Alta Municipal Building in Zone X. The 

facility was not damaged by flooding.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-43

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

5.3.3 Performance Relative to Wind

The midrise municipal buildings investigated showed no evidence of failure of their main structural 

elements or the MWFRS. The performance of the openings, windows, and roofs varied considerably 

with some experiencing significant damage and others slight damage. 

The PRDOJ Building experienced no structural failures in the walls, roof, or foundations. However, 

water entered the building through broken windows and displaced rooftop equipment. While the 

lower level windows had shutters installed, many of the shutters failed, resulting in windows damage 

and breakage. Water was still entering the building at the time of the MAT visit, wetting the floors 

and causing air quality problems and loss of contents.

Culebra Municipal Building showed very good wind performance with little to no rooftop equipment 

damage, no damage to the metal roof portion of the building and some minor leakage from a cut 

in the membrane roof covering from debris. 

5.3.3.1 Main Wind Force Resisting System

The Main Wind Force Resisting System (MWFRS) of the midrise building performed well during 

the storms of 2017. During the MAT investigations in October and December 2017, no structural 

failures were noted of the structural core or main elements of the buildings. The mid-rise frames 

tended to be reinforced concrete frames with concrete columns, beams and slabs. 

5.3.3.2 Openings

The PRDOJ building had numerous window breakages from debris impact during Hurricanes Irma 

and Maria (Figure 5-65 through 5-70). Windows failed at all levels from the top to the base of the 

building. The upper floor window systems failed when their frames were pushed into the building 

after screws joining the frame and the framed opening broke (Figure 5-66 through 5-68). Metal 

panel shutters installed in tracks protected lower-level windows. These failed when the shutters and 

tracks were pulled free from their locations due to undersized anchors (Figure 5-70).

Figure 5-65: View of the northwest side of the 

PRDOJ building with numerous windows broken.

Figure 5-66: Window frames pushed into the PRDOJ 

building at the top floor due to the failure of frameto-structure anchors, (red arrows).
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PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Figure 5-67: View of the undersized anchorage 

location, (red arrows) in the window frame at the 

PRDOJ building.

Figure 5-68: The screws that held the window frame 

in place bent and pulled through the window frame 

at the PRDOJ building. The anchors (red circles), 

were too small and too few in number.

Figure 5-69: A shattered window (red arrow) allowed 

water and wind into the PRDOJ building at this location, 

inundating the documents on the adjacent shelf.

Figure 5-70: Left, shutters protecting lower 

floor windows pulled off the PRDOJ building, 

exposing the glass behind; right, the anchors 

were undersized, of the wrong type, and too 

few in number.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-45

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

The Vega Alta Municipal Building had storm shutters only on windows that faced east (Figure 5-71). 

The windows that face north, south and west sides of the building had no glazing protection and, 

some glazing failures and damage were observed on these sides. This damage in combination with 

rooftop equipment failures resulted in unusable floors.

Figure 5-71: Vega Alta Municipal Building had shutters on only 

the east side windows (red arrows). No shutters or opening 

protection is present on windows on this side of the building.

The Toa Baja Municipal Building had no flooding, but roof damage and glazing damage (Figure 

5-72) allowed water intrusion that required the building to be closed. Mold grew in the building due 

to moisture. The building used materials that are more typical of construction practices elsewhere 

in the US than of Puerto Rico, such as drywall and acoustical ceilings. These materials are more 

vulnerable to mold if building envelope breaches and loss of power for air handling occur. The 

building had no natural ventilation, further contributing to mold growth. 

Figure 5-72: Glazing damage (red arrow) at Toa Baja 

Municipal Building.
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PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Bayamón Municipal Building deployed metal shutters on some first-floor and larger upper-story 

windows (Figure 5-73). However, some unprotected window glazing was broken by high winds and/

or wind-borne debris impacts, leading to water intrusion (Figure 5-74).

Figure 5-73: Metal shutters protected some 

upper-story glazed windows at Bayamón 

Municipal Building.

Figure 5-74: Broken window glazing (red 

arrows) at Bayamón Municipal Building.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-47

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

5.3.3.3 Roof System

Although the roof covering at the PRDOJ had a few minor leaks, the roof remained essentially 

intact. No major roofing failures were noted during the MAT site visits. The top roof height of the 

PRDOJ is higher than the surrounding buildings. Due to the height of the building relative to its 

neighbors, the building likely did not experience much wind-borne debris from off-site impacting 

the roof during the hurricane.

The Vega Alta Municipal Building saw roof leaks from various sources such as membrane damage 

(Figure 5-75) and flashing pull-back.

 

Figure 5-75: Vega Alta 

Municipal Building had roof 

leaks. Flashing can be seen 

displaced at the mechanical 

area of the roof. Water 

entered this location as 

well as others.

The Toa Baja Municipal Building had no flooding, but roof damage and glazing damage led to 

water intrusion that necessitated closing the building due to concerns about mold. 

At the Culebra Municipal Building, the roof membrane was punctured (Figure 5-76), likely from 

wind-borne debris, and caused water intrusion into the building. The building had drop ceilings 

and dry wall that were wet and developed mold (Figure 5-84). However, the metal portions of the 

roof fared very well (Figure 5-77). 
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Figure 5-76: Membrane roof covering at Culebra City Hall punctured (red arrow) during hurricane winds led to 

water intrusion in building that damaged acoustical ceilings (yellow arrow) and drywall.

Figure 5-77: Metal roof 

covering at Culebra 

Municipal Building 

performed well. There is 

no evidence of corrosion 

from this view.

At Bayamón Municipal Building, the MAT was told that water intrusion through the roof had 

occurred, although visible evidence of roof damage (e.g., roof membrane punctures) was not 

observed.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-49

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

5.3.3.4 Rooftop Equipment

The PRDOJ rooftop equipment suffered considerable damage. Lightning protection systems, 

rooftop HVAC units, and rooftop cooling towers were damaged by winds and debris in the 

hurricanes (Figure 5-78). Rooftop HVAC units mounted on pads were dislodged (Figure 5-79) and 

blown across the roof, while a rooftop fan was lost entirely (Figure 5-80). A door in a rooftop cooling 

tower collapsed into the tower due to debris impact (Figure 5-81). Given the elevation of the cooling 

towers and a degree of protection from the walls, the impact damage was surprising and revealed 

unexpected vulnerabilities. 

Figure 5-78: The lighting 

protection air terminals 

(green arrow) tore free 

from their anchorages (red 

arrow) atop the PRDOJ 

building. Rooftop AC units 

were also displaced (blue 

arrow).

Figure 5-79: HVAC 

equipment was blown off 

equipment pads at the 

roof level of the PRDOJ 

building. One HVAC 

condenser has been blown 

to the edge of the building 

(yellow circle).
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PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Figure 5-80: A rooftop fan 

unit is missing from this 

location atop the PRDOJ 

building (yellow circle).

Figure 5-81: View of a 

service access door to the 

rooftop cooling towers 

atop the PRDOJ building. 

The door was driven into 

the cooling tower by 

debris impact (red arrow).

While Vega Alta Municipal Building is located somewhat inland and the mechanical equipment was 

located in a recessed part of the roof, it still suffered considerable damage (Figure 5-82). The HVAC 

condenser units had been moved off their pedestals and had toppled over in some cases (Figure 

5-83). The access panels were blown off as well on several units. Conduit that provided connections 

for control wires and for power were broken in places. These breaches in conjunction with glazing 

damage lead to leaks that rendered rooms unusable at the facility. 

 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 5-51

PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

Figure 5-82: View of rooftop mechanical equipment displaced and damaged by the hurricane winds. Left, the 

access panels were blown off (yellow circle). Right, the units were moved off their mounting pedestals (red 

arrow).

Figure 5-83: View of rooftop 

mechanical equipment displaced 

(yellow circle) and damaged by the 

hurricane winds.

At Culebra Municipal Building, most rooftop equipment was mechanically anchored and fared well. 

The equipment was partly protected by a parapet wall and sat in a mechanical well between several 

higher roofs. Some fasteners were beginning to corrode, but they were intact (Figure 5-84).

Bayamón Municipal Building was observed to have some equipment screwed to curbs (Figure 5-85, 

left), while other equipment was inadequately secured. In Figure 5-85 (right), an AC condenser rests 

unsecured on plastic supports. However, significantly displaced equipment was not observed.

5.3.4 Impacts to Operations 

Impacts to operations for these facilities may be classified as being primarily caused by water 

intrusion or loss of power. Loss of power exacerbated damage due to water intrusion by preventing 

clean-up and mitigation using equipment including air conditioners, fans, and dehumidifiers.
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Figure 5-84: Mechanically attached rooftop equipment performed well at Culebra Municipal Building. Some 

fasteners were corroded (red arrow) but did not fail.

5.3.4.1 Impacts from Water Intrusion

The PRDOJ building was unable to be occupied for months due to water inundation. As of July 2018, 

the building is still unoccupied, and the staff work from various locations in San Juan. Many PRDOJ 

files exist only in hardcopy and were damaged by water. While these files undergo restoration by 

document preservation experts, PRDOJ is impaired in addressing its workload. 

Water still enters the building and floors are wetted by rains. Prolonged wet conditions have created 

air quality hazards. Addressing these problems has also exposed legacy environmental hazards such 

as the presence of lead and asbestos, delaying recovery.

The Toa Baja Municipal Building was uninhabitable at the time of the MAT visit due to glazing 

damage, roof damage, and lack of power. The building envelope damage allowed water to continue 

to enter the building. 

Figure 5-85: Rooftop equipment at Bayamón Municipal Building including, left, HVAC unit attached with screws 

to a curb; right, an AC condenser resting on plastic supports without anchoring. Rooftop equipment was not 

significantly displaced during Hurricanes Irma and Maria.

The Culebra Municipal Building was largely unaffected, having only minor flooding of a utility 

room when a sump pump failed. The building was essentially unaffected, as this small mechanical 

utility room could still be used.
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PERFORMANCE OF HOSPITALS, PUBLIC BUILDINGS, AND MID-RISE BUILDINGS

A main wing of the Bayamón Municipal Building was operational at the time of the MAT visit. 

This wing was observed to have openings and rooftop equipment failures; however, an HVAC 

system, powered by a generator, provided ventilation. A separate wing that experienced rooftop and 

openings damage was not operational at the time of the MAT visit. This wing did not have backup 

power or proper ventilation and hazardous conditions prevented reoccupation.

5.3.4.2 Impacts from Loss of Power 

Lack of power has slowed the recovery and reoccupation of the PRDOJ Building, as there was no 

practical means to run HVAC equipment, fans, or dehumidification gear. Power was restored to 

some floors after several months along with some elevator service. However, the HVAC system is nonfunctional, and the building envelope is still breached. The lack of air movement, lack of moisture 

and humidity control, and growth of mold and mildew have delayed recovery.

Toa Baja Municipal Building was closed and unusable due in large part to the lack of power. While 

the building had no flood damage, water from the roof and some broken windows infiltrated the 

building. Air handling equipment could not be run, and there is no natural ventilation. As a result, 

indoor air quality deteriorated, and officials cited mold growth. The building also used some 

finish materials, such as drywall gypsum interior walls and fixed windows, typical of finishes used 

elsewhere in the U.S., that are less tolerant of humidity and moisture than those commonly used in 

Puerto Rico. 

Impacts to the Bayamón Municipal Building differed between the two wings, which were designed 

differently: One wing was able to be used because it had natural ventilation, while a large portion 

of the building was unusable due to lack of power to run air-handling equipment. The loss of air 

handling resulted in extensive air quality problems and mold growth.

5.4 Successes Since Previous Disasters

All four fire stations discussed in this MAT report had been equipped with hazard-resistant shutters 

with HMA funding in 2001 under the program discussed in 1.3.3 Other FEMA Hazard Mitigation. 

Additionally, a number of public buildings received wind retrofits including shutters following 

Hurricane Irene in 2011. Shutter performance was successful in every case the MAT observed when 

shutters were fully deployed. In one case, that of the Palmas del Mar Fire Station, some shutters 

were not in place at the time of the event, allowing windows to be damaged by wind-borne debris. 

This damage illustrates the need for an adequate operations and maintenance plan and execution 

of the plan. Additionally, impact-resistant shutters cannot prevent water intrusion through jalousie 

windows, which are inherently unable to prevent water from seeping between their louvers. 

The Culebra Community Health Center and Municipal Building had been equipped with hurricane 

shutters and/or hurricane-resistant windows by the HMGP-funded Project Impact Culebra in 1999. 

The MAT was not able to determine whether these original features were still present; however, 

opening performance at both facilities was good, with glazing undamaged at the Municipal Building 

and limited water intrusion through openings at both facilities.

HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 6-1

HURRICANES

IRMA AND MARIA

IN PUERTO RICO 6

MITIGATION ASSESSMENT TEAM REPORT

Solar Installations

The MAT observed multiple types of solar installations in Puerto 

Rico. The solar installations observed were either photovoltaic 

(PV) power systems or solar water heaters.

PV systems were observed on residential and non-residential buildings, while solar water heaters 

were only observed on residential buildings. Structurally, solar installations can be ground- or roofmounted. The observed ground-mounted systems were typically large power-generating facilities 

(solar farms). Performance within and among these categories varied widely, as discussed below.

6.1 Ground-Mounted 

Solar Arrays

The MAT observed large ground-mounted solar 

photovoltaic (PV) arrays in Humacao, Isabela, 

and San Juan (Figure 6-1). Observations are 

focused on the ground-mount structures and 

panel performance. Because of the differences 

in wind speeds and local terrain features, few 

direct comparisons of performance can be 

made among the three sites.

DESIGN GUIDANCE FOR GROUND-MOUNTED 

PV ARRAYS

ASCE 7-16 does not provide criteria for 

determining wind loads on ground-mounted PV 

systems. However, some guidance is provided in 

SEAOC PV2-17.

FM Global Loss Prevention Data Sheet 7-106 

provides guidelines and recommendations for the 

design, installation, and maintenance of groundmounted PV systems.
6-2 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

SOLAR INSTALLATIONS

P U E R T O R I C O

ISLA DE

CULEBRA

ISLA

VIEQUES

C a r i b b e a n S e a

A t l a n t i c

O c e a n

Arecibo

Fajardo

Guayama

Ponce

Mayagüez

Rincón

Humacao

San Juan

Solar Farms

Reden Solar Array, Humacao

Puerto Rico Convention Center Solar Array, San Juan

Oriana Solar Array 1, Isabela

!(1

!(2

!(1

!(2

!(3

!(3

0 20 40 10

Figure 6-1: Location map showing ground-mounted PV facilities visited by the MAT.

Miles μ

6.1.1 Reden Solar Array, Humacao

In Humacao, a large ground-mounted PV system belonging to Reden Solar (formerly Fonroche) 

experienced major damage from high winds. Located approximately 2.5 miles (4 kilometers) from 

the eastern coast of Puerto Rico, Humacao experienced severe wind speeds estimated at 140 mph 

(225 kph) at 33 feet (10 meters) above ground over flat open terrain (Figure 1-2 and Figure 1-7). Two 

phases of the facility experienced significantly different effects from the hurricane winds. The first 

20-megawatt (MW) phase was constructed in 2016, followed by the second 20 MW phase, which was 

completed in 2017. The Phase 2 area of the facility was severely impacted by hurricane wind forces 

and wind-borne debris, while Phase 1 performed relatively well (Figure 6-2, left). Based upon aerial 

imagery, it is estimated that 75 percent of the solar panels in Phase 2 were damaged or removed 

from the ground-mount structure, compared to about 25 percent for Phase 1. 

Several differences were identified between the Phase 1 and Phase 2 PV arrays (Figure 6-2) during 

the MAT assessment:

● Location: The overview (Figure 6-2, middle) illustrates how the system is positioned. Phase 1 

is mostly located on the left side in the photograph, while Phase 2 is to the right. It is possible 

that the two phases were impacted differently due to the topographic effects created by the 

surroundings. 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 6-3

SOLAR INSTALLATIONS

● Elevation above grade: The PV panels located on Phase 1 (Figure 6-2, left) were installed 

closer to the ground (low end 26 inches [66 centimeters] above grade, high end 58 inches 

[147 centimeters]). The panels located on Phase 2 (Figure 6-2, right) were installed at a higher 

elevation (42-72 inches [108-183 centimeters]) above grade. 

● Installation: The cantilevered length of the top panel differed between the two phases. On 

Phase 1, the upper panel was cantilevered 18 inches (46 centimeters). On Phase 2, the upper 

panel was cantilevered 24 inches (61 centimeters). Because the upper end of the array was likely 

exposed to more wind pressure, the extra six inches of overhang may have played a role in the 

failure.

Figure 6-2: High wind damage to ground-mounted photovoltaic (PV) systems in the Reden Solar Array, 

Humacao, showing panels in Phase 1, left; hill separating the two phases, center; and Phase 2, right.

The Reden solar array in Humacao consists of 1 x 2 meter (39 x 78 inch) panels installed on fixed 

tilt systems. Each frame has two rows of panels and is angled for solar exposure from south (low) 

to north (high). The structural members of the ground-mounted system are composed of openchannel (C-shaped) cold-formed metal framing sections. Each pair of posts supports a sloped beam. 

Two to four lateral rails run perpendicular to the sloped beams (Figure 6-3) and carry the solar 

panels. 

 

Figure 6-3: Reden solar array in Humacao, with groundmounted posts (green arrow), sloped beams (blue arrows), 

and lateral rails (red arrow), that directly support the PV 

panels. In this image some of the panels have been lifted off 

the ground-mount structure, with the failure occurring at the 

panel clips.
6-4 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

SOLAR INSTALLATIONS

The panels are attached to the lateral rails through hat-shaped bolted clips. Two images of the 

hat-shaped clips (Figure 6-4) display the side and overhead views of the PV attachment to the 

ground-mount structure. Each clip has only one bolt, and four clips secure a single PV panel. The 

lack of redundancy in this system means that if one clip or bolt fails, an entire panel will likely be 

lifted off the ground-mount structure. With a single nut, the bolted connection is also susceptible 

to loosening as winds cause the panels to vibrate. During numerous wind cycles, as can occur in a 

hurricane, the panel clips may eventually become loose enough to allow wind pressure to lift panels 

off the ground-mount structure (Figure 6-5). 

Figure 6-4: Reden solar 

array in Humacao: Left, 

side view of a hat-shaped 

clip showing its bolted 

connection to the lateral 

rail member underneath. 

Right, top view showing 

that a single bolt secures 

it to the rail.

Figure 6-5: Reden solar array in Humacao: A deformed hatshaped clip still bolted to its supporting lateral rail. The PV 

panel to the left was lifted out of position when the hat-shaped 

clip could not resist the wind uplift pressures and was bent 

upward.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 6-5

SOLAR INSTALLATIONS

In addition to clip failure, the lateral rails and lateral rail angle connections exhibited deformation 

due to debris impacts or wind pressures, which lifted panels out of position, leaving the panels still 

connected to the rails (Figure 6-6 and Figure 6-7). 

Figure 6-6: Reden solar 

array in Humacao: In 

this image, only the bent 

angle (red circle), remains 

after the steel lateral rail 

and bolted attachment 

were pried away in the 

hurricane.

Figure 6-7: Reden solar array in Humacao: Three deformed steel lateral rails (red arrows). In 

a number of cases the C-shaped lateral rail connections were unable to maintain connection 

to the steel beams in the high winds.
6-6 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

SOLAR INSTALLATIONS

As the PV arrays and ground-mount structure were lifted and pried off their supports, these objects 

became wind-borne debris that impacted other ground-mounted arrays. The successive failure of 

many of the PV rows in Phase 2 demonstrates the devastating effects of components that begin 

to fail and add wind-borne debris impacts to systems already pushed to the limit of failure from 

wind pressures. As a result, some areas of Phase 2 contained only a small number of panels in their 

original positions (Figure 6-8). 

Figure 6-8: Reden solar array in Humacao: Aerial view of the Phase 2 Array with most PV panels removed from 

their ground-mount supports and many structural members damaged.

6.1.2 Oriana Solar Array 1

Oriana Solar Array 1 is in northwestern Puerto Rico near Isabela, approximately 3 miles (5 

kilometers) from the coast and was constructed in 20161. The PV panels at Oriana Solar Array 1 

experienced lower wind speeds of approximately 90 mph (145 kph) at 33 feet (10 meters) above 

ground over flat open terrain (Figure 1-2 and Figure 1-7) and appeared to have a more robust 

structural support system than the Reden array in Humacao. Overall, this array demonstrated far 

less damage than the Reden site (Figure 6-9). For a typical ground-mount structure, approximately 

10 percent of the solar panels were damaged or removed. 

1 Oriana Solar Array 2 is located approximately 1.4 miles (2 kilometers) north of Oriana Solar Array 1, but the MAT 

did not visit this site. Post-Maria NOAA imagery suggests Array 2 was considerably less damaged than Array 1.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 6-7

SOLAR INSTALLATIONS

Figure 6-9: Oriana Solar 

Array 1: Aerial view of 

one of the more damaged 

areas within the Oriana 

Solar Array.

The arrays have two rows of panels and are angled for solar exposure from south (low side) to north 

(high side). Each array is supported by cold-formed metal framing using open-channel (C-shaped) 

sections (Figure 6-10). Each pair of posts supports a beam member, which in turn carries the lateral 

rails running perpendicular to the beams. A set of two lateral rails bears a row of PV panels. 

The Oriana Solar Array included additional structural bracing such as bracing between posts both 

perpendicular and, in some cases, parallel to the lateral rails (Figure 6-10 and Figure 6-11). Some 

of the PV arrays also utilized horizontal bracing (Figure 6-11). This structural member helps the PV 

array resist wind loads on the ground-mount system and assists the PV panels in bracing the lateral 

rails.

Figure 6-10: Oriana Solar Array 1, 

showing ground-mounted posts 

(green arrows), sloped beams 

(blue arrows), and lateral rails (red 

arrows), directly supporting the PV 

panels. This array also has a brace 

connecting each row of posts (pink 

arrows).
6-8 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

SOLAR INSTALLATIONS

Figure 6-11: Oriana Solar Array 1: The brace connecting each 

row of posts (pink arrows) provides additional strength to the 

posts and helps limit the overall sway or movement of the PV 

array perpendicular to the lateral rails (red arrow). The yellow 

arrow in the image points to a brace which connects posts 

parallel to the lateral rails. This brace will assist the system in 

a similar manner in the opposite direction.

Figure 6-12: Oriana Solar Array 1: The horizontal brace (blue 

arrow) connecting rows of lateral rails (red arrow) helps 

distribute wind loads through the structural system and utilize 

less dependence upon the PV panels to brace the structural 

system. The horizontal brace also helps resist torsional or 

twisting action on the ground-mount system.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 6-9

SOLAR INSTALLATIONS

Although fewer solar panels were lifted off the ground-mount structure, most failures seemed to 

be generated at the hat-clip connection between the PV panel and the steel lateral rails. Figure 

6-13 shows a common example of a missing hat clip where an adjacent PV panel was removed from 

the PV array. Typically, hat clips were secured to the lateral rails with a single steel nut (Figure 

6-14). The winds created by hurricanes can induce fluttering of structural components, and single 

steel nuts are susceptible to loosening through vibration. Once loose, the PV panels may begin to 

twist and impose unexpected loading conditions, leading to the panel being blown off the groundmount supports.

Figure 6-13: Oriana Solar Array 1: Steel lateral rail 

missing bolt and Hat-clip which held the adjacent PV 

panel.

Figure 6-14: Oriana Solar Array 1: Steel 

lateral rail (yellow arrow) still bolted to 

the clip which secures the PV panel to 

the ground-mount system. Notice the 

single steel nut (red arrow) which could 

back off the bolt.
6-10 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

SOLAR INSTALLATIONS

6.1.3 Puerto Rico Convention Center Solar Array

The Puerto Rico Convention Center in San Juan has approximately 17,000 solar panels located over 

parking spaces which offer shade and energy production. The system produces around 8,000 MWh 

of electricity annually (Trina Solar 2018) and was constructed in 2014. Each array is approximately 

330 feet (100 meters) long by 45 feet (14 meters) wide. The steel ground-mount structure and solar 

panels exhibited good performance and resilience during Hurricane Maria. Although wind speeds 

were estimated at 140 mph (225 kph) at 33 feet (10 meters) above ground over flat open terrain 

(Figure 1-2 and Figure 1-7), the system appeared to have lost fewer than 5 percent of the PV panels 

to debris impact and wind uplift (Figure 6-15). 

Figure 6-15: Puerto Rico Convention Center Solar Array: Some PV panels were lost (red circles) from these 

carports. Based upon aerial imagery, it is estimated that fewer than 5 percent of the panels at this site were 

damaged or removed (Civil Air Patrol 2017).
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 6-11

SOLAR INSTALLATIONS

The ground-mount structures at the site are predominantly composed of a single steel column 

supporting a steel girder with a tapered cross-section. The girder cantilevers beyond the column 

in each direction with assistance from steel kickers. Each girder then carries four steel beams, 

which hold steel lateral rails that directly support the PV panels (Figure 6-16). The PV panels were 

connected to the steel rails at four locations using a steel bolt, a washer, and a nut. As mentioned 

in previous sections, the use of only a single nut raises concerns that the nut could loosen in high 

winds, allowing the panels to flutter. No damage was observed to the structure.

Figure 6-16: Puerto Rico 

Convention Center Solar 

Array, showing structural 

members supporting 

the solar array looking 

from the underside of 

the canopy. The arrows 

designate the following 

structural members: steel 

column (green arrow), 

tapered steel girder 

(yellow arrows), steel 

kickers (pink arrows) 

supporting girder, steel 

beams (blue arrows) 

running perpendicular to 

the girder, steel lateral 

rails (red arrows) directly 

supporting the PV panels.

6.2 Rooftop Solar Equipment

The MAT observed rooftop solar equipment including solar water heaters and PV power systems. 

The solar water heater industry in Puerto Rico dates to the 1960s, and today, both technologies are 

viable ways for building owners in Puerto Rico to reduce energy costs. 

The solar water heater industry in Puerto Rico benefited from Puerto Rico’s inclusion in the 

U.S. Department of Energy Weatherization Assistance Program (WAP) funded by the American 

Recovery and Reinvestment Act (ARRA) of 2009. Puerto Rico received $65 million in WAP funding, 

weatherizing over 15,000 housing units between 2010 and 2011, nearly all single-family homes. 

Seventy-three percent of these (about 11,173 units) received a solar water heater of either the flat 

plate collector or evacuated tube type. Solar water heaters were only installed on homes with 

concrete roofs (Tonn and Rose 2015).

The 2011 Puerto Rico Building Code drove solar water heater adoption by requiring that only solar 

water heaters be used for new one- and two-family homes and townhouses, with no exemptions 
6-12 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

SOLAR INSTALLATIONS

(Energy.gov 2018a). Similarly, the implementation of PV power systems in residential and 

commercial applications has become feasible since the Government of Puerto Rico enacted netmetering legislation in August 2007 (Energy.gov 2018b). 

PREPA, with the Puerto Rico Infrastructure Financing Authority (PRIFA; Autoridad para el 

Financiamiento de la Infraestructura de Puerto Rico), has developed several solar rebate programs 

including the Solar Water Heater Rebate Program (OpenEI.org 2018) and the Sun Energy Rebate 

Program (OpenEI.org 2018). 

Wind forces on PV panels are not specifically addressed in the 2011 PRBC, which references the 

2009 IBC© and ASCE 7-05 wind load provisions. With the adoption of the 2018 I-Codes, which 

reference ASCE 7-16, engineers will have guidelines to estimate wind loads on rooftop PV power 

systems.

6.2.1 Residential Solar Water Heaters

Overall, the observed performance of solar water heaters was excellent. This may be partly due to 

the fact that panels on many water heater systems are attached to a more robust frame that also 

supports the heavy water tank. The weight of the collector is also likely greater that of a PV array of 

similar area, increasing resistance to wind forces. Also, the majority of these systems are installed 

in concrete homes. Typical anchoring systems used in concrete slab roof systems in Puerto Rico are 

shown in Figure 6-17.

Figure 6-17: Typical 

anchoring system used 

for rooftop equipment in 

concrete slab roof, with, 

top, concrete anchoring 

system using an expansion 

plug placed in the roof 

slab after drilling a hole, 

bottom, a concrete 

expansion anchorage bolt.

WEDGE, SLEEVE, OR

EXPANSION ANCHOR

THREADED ANCHOR

DOWEL AND EPOXY ANCHOR STRIKE ANCHOR

CONCRETE CONCRETE

CONCRETE CONCRETE
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 6-13

SOLAR INSTALLATIONS

MAT field observations revealed that the vast majority of the assessed solar water heaters installed 

on concrete roofs performed well, with minimal damage associated with wind forces. Figure 6-18 

shows a system installed on a NSHP home in Canóvanas; the water heater was not damaged. Figure 

6-19 shows a damaged solar water heater installed on a two-story house in the community of El 

Negro in Yabucoa; in this case, the solar collector panel of the heating system is missing.

Figure 6-18: Solar water 

heater unit with flat 

solar collector panel in 

Canóvanas.

Figure 6-19: Solar water 

heater system missing 

solar collector panel on 

the flat slab concrete roof 

of a two-story concrete 

house in El Negro, 

Yabucoa.
6-14 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

SOLAR INSTALLATIONS

gust 3-sec (mph), 

9/20/2017 11:30, 120.0

0

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0

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9/20/2017 0:00 9/20/2017 6:00 9/20/2017 12:00 9/20/2017 18:00 9/21/2017 0:00 Wind Direction (degrees) Wind Speed (mph)

UTC

CariCOOS/WeatherFlow Weather Station, Gurabo, Puerto Rico

Station ID XGUR - 33ft above ground (site elevation 172 ft)

Lat. 18.25623 Lon. -65.99167

gust 3-sec (mph) average 1 min (mph) lull 3-sec (mph) direction (deg.)

pressure (mb), 9/20/2017 

11:30, 943.4

940

950

960

970

980

990

1000

9/20/2017 0:00 9/20/2017 6:00 9/20/2017 12:00 9/20/2017 18:00 9/21/2017 0:00

Pressure (mb)

UTC

pressure (mb)

Figure 6-20: Reference wind speed near Caguas at CariCOOS/Weather Flow meteorological station, Gurabo.

Figure 6-21 shows a solar water heater installed on a one-story house in Caguas; in this case, the 

system shows no signs of wind damage. A nearby CariCOOS/WeatherFlow weather station at the 

Agricultural Experimental Station of the UPRM approximately 5 miles (8 kilometers) northeast 

from the house reported a maximum wind gust of 120 mph (193 kph) on September 20, 2017, at 

7:30 AM AST (Figure 6-20). 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 6-15

SOLAR INSTALLATIONS

Figure 6-21: Solar water 

heater system with no 

evident wind damage on 

a concrete slab roof of a 

one-story concrete house 

in Caguas.

6.2.2 Residential Photovoltaic Systems 

In contrast to the consistently good performance of solar water heaters, the performance of PV 

power systems varied depending on the type of anchoring system and the type of clamping system 

connecting the PV panels to the aluminum frame. In a typical configuration, PV panels are attached 

to an aluminum frame system and are typically connected to the framing system at the corners 

(four points) using a clamp. The MAT observed PV panels that had failed due to wind loads, windborne-debris impact, and clamping mechanism failure.

Figure 6-22: PV power 

system installed on a 

flat concrete slab roof in 

Naguabo with no visible 

damage.
6-16 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

SOLAR INSTALLATIONS

Most of the wind failures and damage associated with PV systems were associated with the failure 

of the PV panel, failure of the panel connections to the framing system (typical clamp connector 

mechanism), and, in some cases, lack of proper anchoring to the roof.

Figure 6-23 shows a PV system installed on the roof of a one-story concrete house located in Naguabo 

with no evident wind damage.

Figure 6-23: PV power system installed on a flat concrete slab roof in Caguas with no visible damage.

In Caguas, the MAT observed a one-story concrete house with a PV system installed on the roof 

(Figure 6-24). In this case, there was no wind damage to the PV panels, although there was wind 

damage to the clay roof. Figure 6-25 is a close-up view of the clamp joining the PV panel to the 

aluminum framing. Figure 6-26 shows the anchoring system of the aluminum framing to the 

concrete roof. The front portion of the house has an inclined roof with aesthetic ceramic roof 

tiles; some of the tiles were damaged by high winds, but ceramic tile debris did not damage the PV 

panels. The homeowner told MAT members that the system had no battery bank and that the house, 

therefore, had no electrical power at the time of assessment. The homeowner relied on portable gas 

power generators.

Figure 6-24: Clamp on a PV power system installed 

on a flat concrete slab roof in Caguas.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 6-17

SOLAR INSTALLATIONS

Figure 6-25: Left, PV power system anchored to a flat concrete roof slab in Caguas; right, closeup of bolted 

connection.

6.2.3 Non-Residential Photovoltaic Systems

This section represents a summary of MAT observations of non-residential rooftop PV systems. The 

MAT did not encounter solar water heaters in use on non-residential buildings.

6.2.3.1 Susana Centeno Family Health Center, Vieques

The Susana Centeno Family Health Center is a general acute care hospital. Its primary function is 

to provide inpatient diagnostic and therapeutic services for a variety of medical conditions, both 

surgical and non-surgical, to the community. The facilities were built in 1996, and the Vieques Rural 

Outpatient Clinic of the Veterans Affairs Caribbean Healthcare System, which is a Satellite of the 

San Juan Veterans Affairs Medical Center, was established on January 29, 2011, to improve access to 

Primary Care services for veterans in Vieques. 

It is estimated that wind speeds in Vieques were near the design wind speed per ASCE 7-05, which is 

145 mph (233 kph). A nearby weather station located 18 miles (29 kilometers) northeast of Vieques 

at the Culebrita Lighthouse reported a peak three-second wind gust of 138 mph (222 kph), and it is 

estimated that the maximum wind speeds were from the southeast (Figure 6-36).

The MAT assessed the PV power system installed on the roof of the acute general hospital Susana 

Centeno Family Health Center in Vieques. The PV system was installed in 2016 with a capacity of 

30 KW with a cost investment of $126,0002 (State Office of Public Energy Policy 2016). The PV 

panels shown in Figure 6-26 are on the south portion of the roof edge. For Hurricane Maria, this 

was the windward edge of the roof building that received the strongest winds. For this facility, the 

performance of the PV panels with respect to wind loads was poor. Panels were observed to have 

failed due to wind-borne debris impact (Figure 6-27) and failure of the panels’ clamp connection 

(Figure 6-30). Figures 6-28 through 6-33 show close-up views of the clamping mechanism used to 

attach the PV panels to the aluminum frame system; the clamp connection consisted of stainless-steel 

2 This is approximately $155,000 in inflation-adjusted September 2017 dollars. 
6-18 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

SOLAR INSTALLATIONS

custom bolts that slid through an aluminum slotted section, tightened using regular stainless-steel 

nuts with a custom clamping mechanism. In addition, the anchoring of the conduit system to the 

roof was insufficient to withstand the high winds and performed poorly (Figure 6-34).

Figure 6-26: PV power 

system installed at Susana 

Centeno Family Health 

Center in Vieques. The 

system had significant 

wind damage due to 

wind-borne debris impact 

and clamp failures.

Figure 6-27: PV power 

system installed at 

Susana Centeno Family 

Health Center in Vieques. 

Close-up view showing 

PV panels damaged by 

impact debris.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 6-19

SOLAR INSTALLATIONS

Figure 6-28: Clamps used 

at Susana Centeno Family 

Health Center.

Figure 6-29: Clamp used to 

hold adjacent PV panels to 

frame.
6-20 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

SOLAR INSTALLATIONS

Figure 6-30: Clamp used to 

attach adjacent PV panels 

to frame.

Figure 6-31: Side view 

of clamp used to attach 

adjacent PV panels to 

frame.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 6-21

SOLAR INSTALLATIONS

Figure 6-32: Close-up view of the anchoring 

connection to the roof concrete slab.

Figure 6-33: Close-up view of the clamping 

mechanizing connection used to hold PV 

panels at the edges.
6-22 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

SOLAR INSTALLATIONS

Figure 6-34: Failure of 

conduit connected to the 

roof used for the PV power 

system.

The PV power system was significantly damaged by the strong wind of Hurricane Maria. At the time 

of the MAT observations, the system was not operational. The system was installed close to the roof 

edge. The aerial shown in Figure 6-35, taken days after Maria, shows that almost the entire first 

two rows of PV panels close to the edge (orange rectangle) of the roof were blown off the railing 

system. The MAT observed that fluttering and vibration of the panels due to wind uplift exerted 

cyclical loading on the clips and frames, contributing to the failure of these components. Windborne debris impacts also affected the PV system. 

Figure 6-35: PV power system installed on the roof of Susana Centeno Family Health Center, Vieques (Source: 

aerial image taken September 24, 2017 [NOAA 2017]).
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 6-23

SOLAR INSTALLATIONS

gust 3-sec (mph), 

9/20/2017 8:44, 137.7

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9/20/2017 0:00 9/20/2017 6:00 9/20/2017 12:00 9/20/2017 18:00 9/21/2017 0:00 Wind Direction (degrees) Wind Speed (mph)

UTC

CariCOOS/WeatherFlow Weather Station, Isla Culebrita, Puerto Rico

Station ID XCUL - 35ft above ground (site elevation 236 ft)

Lat. 18.3137 Lon. -65.227418

gust 3-sec (mph) average 1 min (mph) lull 3-sec (mph) direction (deg.)

pressure (mb), 9/20/2017 

8:39, 957.8

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pressure (mb)

Figure 6-36: Reference wind speed at CariCOOS/WeatherFlow meteorological station, Culebrita.

6.2.3.2 Culebra Ecological School, Culebra

Culebra Ecological School was built after hurricane Georges (1998) to be used as the principal 

shelter facility for the island of Culebra. During the MAT assessment, the PV power system was not 

operating due to lack of maintenance of the battery bank.

It is estimated that wind speeds in Culebra were near the design wind speed per ASCE 7-05, which 

is 145 mph (233 kph). A nearby weather station located 5 miles (8 kilometers) east of Vieques at the 

Culebrita Lighthouse reported a peak three-second wind gust of 138 mph (222 kph) (Figure 6-36).

The MAT assessed the PV power system installed on the roof of Culebra Ecological School (Figure 

6-37). The PV panels are installed on a mono-slope concrete roof with a metal roof covering. The 

panels appeared to be properly anchored to the concrete roof using structural aluminum angles; 

however, the metal roof covering failed on part of the roof due to the high winds. The PV panels were 

located on the windward side of the roof during Hurricane Maria, exposing them to intense winds 

from open water. The metal roof covering was installed on top of rigid insulation foam installed 

between the metal covering and the concrete. The roof had severely corroded along the failure 
6-24 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

SOLAR INSTALLATIONS

zone. It was evident that this corrosion had reduced the structural integrity of the connection of the 

metal roof covering to the concrete slab.

Figure 6-37: Views of the rooftop PV array at Culebra Ecological School, clockwise from top left: undamaged 

portion of the roof, roof covering failure, close-up of structural aluminum angle anchoring system attaching 

the PV panels to the concrete roof, open water exposure for the upwind fetch of the intense winds, close-up 

of failed roof covering section showing exposed rigid insulation foam, view of corrosion on metal roof edge 

flashing on portion of roof with roof covering failure.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 6-25

SOLAR INSTALLATIONS

 6.2.3.3 Zimmer Biomet Facility

Zimmer Biomet is a medical device manufacturer in the Mercedita region of Ponce. After Hurricanes 

Irma and Maria, the company announced that the facility had sustained relatively minor damage 

from the storms (Zimmer Biomet 2017). The company’s manufacturing operations were partially 

restored and were expected to gradually ramp up as central power was brought back online in the 

following months. The facility includes a roof-mounted PV array.

Winds speed near Mercedita may have been below the design wind speed per ASCE 7-05. As 

indicated on ARA wind speed maps (Figure 1-2 and Figure 1-7), estimated wind speed (modeled for 

comparison to ASCE 7 design wind speeds) was in the range of 90–100 mph (145–161 kph). Although 

no nearby ground-truthed wind data is available due to instrument and telecommunications failures, 

a nearby meteorological buoy, located about 12 miles (20 kilometers) south of Mercedita and 

operated by CariCOOS, reported maximum sustained wind of 58 mph (93 kph) with a maximum 

gust of 78 mph (125 kph) at 12:00 PM on September 20, 2017 (Figure 6-38).

gust 5-sec (mph), 

9/20/2017 16:00, 78.9

0

45

90

135

180

225

270

315

360

0

20

40

60

80

100

120

140

160

9/20/2017 0:00 9/20/2017 6:00 9/20/2017 12:00 9/20/2017 18:00 9/21/2017 0:00 Wind Direction (degrees) Wind Speed (mph)

UTC

CariCOOS/WeatherFlow Buoy South of Ponce, Puerto Rico

Station ID 42085 - 13ft above sea level

Lat. 17.860 Lon. -66.524

gust 5-sec (mph) average 8 min (mph) direction (deg.)

pressure (mb), 9/20/2017 

11:00, 983

950

960

970

980

990

1000

1010

9/20/2017 0:00 9/20/2017 6:00 9/20/2017 12:00 9/20/2017 18:00 9/21/2017 0:00

Pressure (mb)

UTC

pressure (mb)

Figure 6-38: Reference wind speed at CariCOOS/WeatherFlow meteorological station buoy south of Ponce. The 

station failed to record some values during Hurricane Maria; therefore, actual wind speeds and pressures at 

this station may be more extreme than those discussed.
6-26 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

SOLAR INSTALLATIONS

The PV power system (Figure 6-39) consisted of eight PV panels installed on an aluminum frame 

system attached to the roof of a concrete structure. After Irma and Maria, only four panels remained 

in place.

Figure 6-39: PV power system at Zimmer Biomet 

in Mercedita, Ponce, which lost four of its eight 

panels.

The PV array was most likely damaged due to insufficient anchorage of the PV panels to the 

aluminum framing (Figure 6-40). Although the estimated wind speed was below the design wind 

speed at this location, wind uplift forces and fluttering effects appear to have caused a partial failure.

Figure 6-40: Close-up views 

of the aluminum framing 

system of the PV power 

system at Zimmer Biomet 

facility in Mercedita, Ponce.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 6-27

SOLAR INSTALLATIONS

COMMUNICATION TOWERS AND WIND TURBINES

The MAT observed multiple failures of communication towers and wind turbines. The failure of these structures 

limited coordination efforts and reduced electrical power generation following the hurricanes. These failures 

create wind-borne debris, which can threaten lives and harm surrounding structures and property. 

Adjacent to a community basketball court in Cayey, a three-legged lattice communication tower failed. The 

communication tower had a triangular steel cross section and failed at the lower third. Figure 6-41 displays 

steel angles which snapped in the hurricanes. The MAT could not definitively establish the cause of failure, but 

wind-borne debris, high winds, or a combination thereof are likely candidates. 

Approximately 7 miles (11 kilometers) east of the failed communication tower in Cayey, another tower 

supporting a doppler radar enclosure (the radome or bubble) was ripped apart by Hurricane Maria (Figure 

6-43). Located on the peak of a mountain at approximately 2,700 feet (823 meters), the radar bubble could not 

withstand the estimated 125 mph (201 kph) wind speeds. However, the steel tower structure demonstrated 

good performance and appeared to suffer no significant damage. 

The Punta de Lima Wind Farm is composed of 13 three-bladed turbines. Located in Naguabo, it began operation 

in 2013. Wind speeds of approximately 130 mph (209 kph) caused severe damage to the turbine blades (Figure 

6-42). Some of the blades were broken off their supports, while other blades appeared shredded by the wind. 

In some cases, all three blades and the top portion of the tower were severed from the tower support.

Figure 6-41: Failure of 

steel communication 

tower in Cayey.

Figure 6-42: Wind 

turbines damaged 

by the hurricanes in 

Naguabo, along the 

northeastern coastline 

of Puerto Rico. Figure 6-43: Failure of radar 

bubble on communication 

tower in Cayey. The tower 

itself appeared undamaged.

HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 7-1

HURRICANES

IRMA AND MARIA

IN PUERTO RICO

7

MITIGATION ASSESSMENT TEAM REPORT

Conclusions and 

Recommendations

The conclusions and recommendations presented in this report 

are based on the MAT’s observations in the areas studied; 

evaluations of relevant codes, standards, and regulations; and 

meetings with Commonwealth and local officials and other 

interested parties.

The conclusions and recommendations are intended not only to assist Puerto Rico communities, 

businesses, and individuals in their recovery, but to help improve the resilience of communities 

and buildings impacted by flood and design-level wind events like Hurricanes Irma and Maria. The 

authors of the MAT Report also wish to acknowledge the actions Puerto Rico has already taken, or is 

taking, to improve resilience consistent with the recommendations found in the report.

7.1 Summary of Conclusions and Recommendations

The 2017 hurricane season was devastating for the residents of Puerto Rico. Hurricane Maria made 

landfall in Puerto Rico as a category 4 hurricane and destroyed or severely damaged much of the 

Commonwealth’s infrastructure. The 3.3 million residents were left without power for months, and 

95 percent of cellular sites were out of service, leading to a complicated and delayed recovery. 
7-2 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

CONCLUSIONS AND RECOMMENDATIONS

The impact of the hurricanes was felt not only in the power and telecommunication sectors, but also 

by individual homeowners. Many of the residences in Puerto Rico are of informal construction, not 

built to a building code or standard. In addition, the advanced age of residential building stock and 

the limited adoption of flood insurance in the Commonwealth have impacted many residents. Irma 

and Maria destroyed thousands of homes and, without proper insurance to assist reconstruction, 

these homeowners’ ability to rebuild is uncertain.

This report provides several recommendations to assist in rebuilding a resilient Puerto Rico. The 

recommendations are presented as guidance for a variety of stakeholders from the public, private 

and non-profit sectors. The following are three especially important recommendations in order of 

urgency, from one requiring immediate action to one which may take longer to implement. 

Recommendation PR-3a. OGPe should finalize the adoption of the latest hazardresistant building codes and standards. To enable new buildings and those that have 

been substantially damaged or will be substantially improved to better resist disasters, 

the latest editions of the building code and reference standards should be considered 

for adoption. OGPe should review the I-Codes and determine the most relevant to adopt 

for the Commonwealth. In addition, Puerto Rico should consider local amendments to 

ensure that the hazard-resistant provisions are not weakened and that local conditions 

are accounted for. 

Recommendation PR-9a. FEMA should consider working with the Insurance Institute 

for Business & Home Safety (IBHS) to conduct a review of private flood insurance 

policies for equivalency and effectiveness. Private flood insurance can offer different 

protections than NFIP policies. Because Puerto Rico’s reliance on private insurance is 

unique in the U.S., a study is warranted after this event to assess the efficacy of private 

insurance on homeowners’ ability to rebuild more quickly while reducing the burden on 

U.S. taxpayers. 

Recommendation PR-35a. Require specific educational and first responder facilities 

to provide a storm shelter. Safe rooms and storm shelters provide buildings or portions 

of buildings that have been designed and constructed to provide life-safety protection 

from high wind events such as hurricanes. Puerto Rico should create a local amendment 

to the PRBC to require that any new facilities constructed for Educational Group E 

Occupancies with an aggregate occupant load of 50 or more (including public and 

private schools, but excluding Group E day-care facilities or Group E occupancies 

accessory to places of religious worship), 911 call stations, emergency operations centers 

and fire, rescue, ambulance and police stations comply with IBC© table 1604.5 as a Risk 

Category IV structure and be provided with a storm shelter constructed in accordance 

with ICC 500©. In addition, OGPe and PRDOH should keep a record of all ICCcompliant community shelters in the Commonwealth.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 7-3

CONCLUSIONS AND RECOMMENDATIONS

7.2 General Conclusions 

Conclusion PR-1

Many of the damaged buildings observed lacked a continuous load path: Most of the buildings 

observed by the MAT that experienced partial or total failure of their structural systems lacked 

a continuous load path. While some buildings experienced failures when individual structural 

members failed, this was not common. The most common type of failure occurred when a 

connection between two structural members failed. When continuous load paths were provided, 

and designs corresponded with what is in the newer codes, the MAT observed no structural failures. 

Recommendation PR-1a. OGPe should develop and publish prescriptive design 

guidance and load path details for designers and contractors. Prescriptive load path 

details and connections suitable for Puerto Rico should be compiled and published for 

use by designers, building officials, and contractors. Although building codes require 

a load path, they do not prescriptively address the connections. Load path details 

specifically addressing framing or MWFRS connections from the roof to the foundation 

should be developed by OGPe to help guide design and construction activities. These 

details will help provide a guide for design professionals to follow and supports a 

consistent set of potential solutions for contractors to select from and implement.

Recommendation PR-1b. OGPe should require construction documents to list critical 

design parameters and show load path connections. OGPe should require that critical 

design parameters for flood, wind, and seismic design, as well as load path connections, 

be clearly listed and shown on building construction documents. A design professional 

should evaluate the number, size, corrosion protection, and type of load path connectors 

necessary to resist the applicable building loads. Construction documents should 

describe and identify load path connections for new construction and construction that 

is being repaired or renovated.

Conclusion PR-2

Many building owners had limited awareness of hurricane hazard risks and vulnerabilities:

Many building owners and occupants had limited or differing awareness or understanding of the 

impending risk of the hurricanes. The vulnerability of their building to flood, wind, and other 

hazards was unknown and many assumed that a specific building type or location ensured their 

personal safety. The understanding of vulnerability may have been due to the information sources 

used to identify the risks, as well as local government recommendations about whether to close the 

facilities during the event. Many building managers and owners may not have been aware of the 

higher risks from such severe hurricane events.

Recommendation PR-2. Facility and building owners should consider performing 

vulnerability assessments for all relevant hazards prior to a natural hazard event. 

Facility and building owners should consider having vulnerability assessments 

performed by a team of knowledgeable professionals to help determine options available 

to mitigate hazards and risks for buildings, including critical facilities, key assets, and 

other structures that may be heavily impacted by a hazardous event. Owners should 
7-4 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

CONCLUSIONS AND RECOMMENDATIONS

identify vulnerabilities and include mitigation measures in short- and long-term 

facility maintenance and capital improvement programs to realistically address the 

vulnerabilities over time, where possible. Facility owners and operators should work with 

key internal staff and design professionals to analyze their facilities, key systems and 

components, operational assumptions, and operation plans to determine a path forward 

for developing project priorities and funding capital improvements that maximize facility 

and operational resiliency. FEMA P-424 Design Guide for Improving School Safety in 

Earthquakes, Floods, and High Winds (FEMA 2010a), FEMA P-543 Design Guide for 

Improving Critical Facility Safety from Flooding and High Winds (FEMA 2007a) and 

FEMA P-577 Design Guide for Improving Hospital Safety in Earthquakes, Floods, and 

High Winds: Providing Protection to People and Buildings (FEMA 2007b) are buildinguse-specific guidance documents that include multi-hazard vulnerability assessment 

checklists for schools, critical facilities, and hospitals, respectively.

7.3 Building Codes, Standards, and Regulations

This section addresses conclusions and recommendations broadly related to codes and policy, 

including those pertaining to the PRBC, permitting and enforcement entities, the I-Codes, NFIP 

and outreach and process stakeholders. 

ADOPTION OF THE 2018 I-CODES

OGPe 2017-10 orders the establishment of a committee to revise and adopt the PRBC based on the 2018 

I-Codes. The proposed codes for adoption include the 2018 Editions of the following:

● International Building Code

● International Energy Conservation Code

● International Existing Building Code

● International Fire Code

● International Fuel and Gas Code

● International Mechanical Code

● International Plumbing Code

● International Private Sewage Disposal Code

● International Residential Code

● International Swimming Pool and Spa Code

FEMA supports OGPe’s decision to update the 2011 PRBC. The 2018 I-Codes include the most recent hazard-resistant provisions and criteria for wind, flood, and seismic hazards. A full discussion of OGPe 2017-10 is provided 

in chapter 2.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 7-5

CONCLUSIONS AND RECOMMENDATIONS

7.3.1 PRBC

Conclusion PR-3

The PRBC can be updated to higher standards: The MAT reviewed the current codes adopted in 

Puerto Rico. The existing PRBC is based on the 2009 I-Codes. Since the adoption of the 2011 PRBC 

the 2012, 2015 and 2018 I-Codes have been published.

Recommendation PR-3a. OGPe should finalize adoption of the latest hazard-resistant 

building codes and standards. To enable new buildings and those that have been 

substantially damaged or will be substantially improved to better resist the impacts 

of hurricanes, floods, and seismic events, the latest edition of the building code and 

reference standards should be considered for adoption. OGPe should review the I-Codes 

and determine the most relevant to adopt for the Commonwealth. In addition, Puerto 

Rico should consider local amendments to ensure that the hazard-resistant provisions 

are not weakened and that local conditions are accounted for. 

Recommendation PR-3b. OGPe should review and update the PRBCs hazard-resistant 

building codes and standards according to a recurring code update cycle. Puerto Rico 

should consider a regular adoption cycle of the building code and update any necessary 

inclusions of the local amendments. 

Conclusion PR-4

Corrosion of fasteners and connectors contributed to building failures throughout Puerto Rico. 

The MAT observed corrosion of fasteners and connectors on many buildings throughout the 

Commonwealth. Building damage due to corrosion notably included roof damage from blown-off 

rooftop equipment secured with fasteners that had corroded, and failures at column base plates for 

Engineered Metal Buildings Systems.

Recommendation PR-4. OGPe should develop a local amendment to the PRBC 

requiring corrosion-resistant materials. OGPe should develop, adopt, implement, and 

enforce requirements for the use of corrosion-resistant materials for exposed structural 

members, connections, fasteners, metal straps, and anchoring mechanisms throughout 

Puerto Rico. Structures should comply with the Corrosive Environments criteria in 

ASCE 24, Section 5.2.2. OGPe should consider reviewing the following documents for 

additional connector information:

1) Technical Bulletin 8: Corrosion Protection for Metal Connectors in Coastal 

Areas (1996) 

2) FEMA P-55, Coastal Construction Manual (2011) 

3) FEMA P-499 Homebuilders Guide to Coastal Construction (2010)
7-6 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

CONCLUSIONS AND RECOMMENDATIONS

Conclusion PR-5

Staged Construction remains unnecessarily exposed to the elements, degrading exposed structural 

elements over time: The MAT observed staged construction throughout the Commonwealth. Much 

of the staged construction appeared to have structural elements that were left exposed to the 

elements for extended periods of time leading to possible corrosion and weakening of the structural 

components. 

Recommendation PR-5a. Protect material during staged construction. Where extended 

open permit periods exist for staged construction, OGPe should provide requirements 

for ensuring that the materials used in construction maintain their original strength 

(i.e., capping exposed rebar). 

Recommendation PR-5b. Limit extended open permit periods for staged or phased 

construction. Staged and phased construction is not addressed with specific time 

durations within the IRC©. OGPe should consider providing guidance on permits and 

construction that is left incomplete (i.e., extended rebar through roof sections for future 

second stories, partially completed additions, etc.) and providing specific timeframes 

after which a new permit would be needed. OGPe should consider adding inspection 

requirements for any permit renewal for staged or phased construction.

7.3.2 Planning Board, OGPe, and Autonomous Municipalities

Conclusion PR-6

OGPe lacks adequate staffing, which has affected hazard-resistant design compliance and 

impacted its ability to enforce the latest building codes and standards: Staffing constraints at 

the Commonwealth and municipal levels have resulted in a minimal approach that often places 

responsibility for the review of hazard-resistant design on the certifying engineer or architect. 

The requirements of the latest building codes make it essential that knowledgeable, trained staff 

be available to review and issue permits, evaluate design and construction packages and inspect 

and enforce the building code. The building code requires new construction (including residential 

construction) and repairs past an identified threshold to have approved permits accompanied with 

design and construction documents that are signed and sealed by a registered design professional. 

The current staffing within OGPe limits the resources available to perform the compliance and 

enforcement activities set forth by the PRBC. 

Recommendation PR-6a. OGPe should consider hiring additional code enforcement 

staff. Working collectively with the Commonwealth and municipalities, OGPe should 

consider hiring, training and supporting additional staff for permit, inspection, and code 

enforcement efforts during post Hurricanes Irma and Maria reconstruction activities. 

After providing the initial surge of support, OGPe can determine the number of staff to 

be retained for long-term support of the building code.

Recommendation PR-6b. The PRPB, OGPe, and autonomous municipalities should 

consider evaluating plan review staffing and guidance. Staffing constraints at the 

Commonwealth and municipal level have resulted in a streamlined approach that 

focuses on only certain structures for inspections. Proper staffing and guidance 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 7-7

CONCLUSIONS AND RECOMMENDATIONS

including checklists could enable a more comprehensive approach to inspections and 

more detailed review of plans for hazard-resistant design compliance.

Recommendation PR-6c. Municipalities should consider participating in the Insurance 

Service Office’s (ISO) Building Codes Effectiveness Grading Schedule (BCEGS). 

Participation in BCEGS would give officials standardized evaluations of a municipality’s 

ability to effectively conduct permit activities and better enforce building codes.

PUERTO RICO HAZARD MITIGATION GRANT PROGRAM (HMPG) FUNDS FOR CODE ADOPTION AND 

ENFORCEMENT

Puerto Rico was awarded an HMGP grant to expedite code adoption in the Commonwealth as it updates its 

building code by adopting the 2018 I-Codes. The grant will fund the formal review of the new codes; the purchase of new code materials for training and use by permit issuers, code enforcement officials, and others as 

needed (including municipal and legislative officials); public education and outreach related to the new codes; 

elected official meetings; public meetings; and other related activities necessary for the formal adoption of the 

updated codes. Performing these activities will allow for expedited adoption of the new codes to ensure they 

are in place during the design phase of disaster recovery activities related to Hurricane Maria.

Puerto Rico was also awarded a second HMGP grant to support post-disaster code enforcement. The grant 

will fund increased staff support for PRPB and OGPe; investment in technological solutions to support operations; establishment of a robust, recurring training curriculum and outreach program; increased data collection 

and sharing between state agencies; and an increased pool of trained experts to maintain and enhance resiliency and compliance in the future. Staff to be hired under this program include 25 Compliance Inspectors 

(PRPB), 145 Project Inspectors (OGPe), 5 Supervisor Inspectors (PRPB), 50 Specialized Inspectors (Licenses and 

Certifications) (OGPe), 21 Technicians (Licenses and Certifications) (OGPe), 12 Buildability Technicians (OGPe); 

12 Uses Technicians (OGPe), and 4 Environmental Compliance Technicians (OGPe). The project also has the goal 

of increasing the number of CFMs in Puerto Rico to 50. Increased revenue from permit fees and fines collected 

during the grant are expected to make these improvements self-sufficient for the long term so that informal 

construction practices may be reduced and eventually eliminated.

Conclusion PR-7

Training was insufficient for code enforcement staff and in-house technical experts: Building 

codes cannot be fully implemented and enforced without adequately trained staff. Discussions with 

OGPe, municipal officials and local experts all echoed the need for additional training of code 

enforcement staff. 

Recommendation PR-7. OGPe should train building code enforcement staff on Puerto 

Rico building code and local amendments. OGPe should provide training on the latest 

codes being adopted. This will help code enforcement staff be better prepared for 

implementing the new code. OGPe will have the opportunity to review policies, answer 

questions, address gaps in guidance or local amendments or issues of concern before 

implementation occurs, making for a smoother transition. Training should include an 

emphasis on hazard-resistant construction and consider ICC© certifications.
7-8 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

CONCLUSIONS AND RECOMMENDATIONS

Conclusion PR-8

Professional licensure and training positively affected quality: Hazard-resistant, code-compliant 

construction requires design and construction professionals to have extensive, up-to-date 

professional training. Without a regulatory regime that confirms and enforces professional licensure 

where appropriate, there can be no assurance that those performing these duties are qualified. 

Recommendation PR-8a. Establish a licensure program for contractors in Puerto Rico.

OGPe should establish a licensure program for contractors and require contractors to 

be licensed. OGPe should consider developing requirements for contractors which may 

include continuing education units (CEU’s) covering design, engineering, codes and 

construction.

Recommendation PR-8b. Train design professionals and contractors on the latest 

hazard-resistant design and construction techniques and best practices. OGPe should 

provide training on the 2018 I-Codes and local amendments to the adopted model code. 

Training should include an emphasis on hazard-resistant design and construction and 

best practices provided in FEMA guidance. This training may include load path design, 

and coastal, flood and wind/seismic design and construction details.

Recommendation PR-8c. Establish public database of actively licensed and registered 

design professionals and contractors. OGPe should work with Professional College 

of Engineers, Puerto Rico College of Architects & Landscape Architects (CAAPPR), 

and Land Surveyors (Colegio de Ingenieros y Agrimensores de Puerto Rico [CIAPR]) 

to establish a public database of licensed and registered design professionals and 

contractors.

PUERTO RICO LAW 19-2017

Law 19-2017 was enacted to unify and consolidate permitting. The law created the Unified Information System 

to integrate Commonwealth and municipal permits and licenses in a consistent manner online. The uniform 

approach to building permits for the Commonwealth and municipalities provides a standardized approach to 

permitting in Puerto Rico and allows design professionals and contractors to follow a single consistent procedure. Under a standardized system, implementation and guidance on complying with hazard-resistant 

provisions in the permitting process can be leveraged throughout the Commonwealth. Law 19-2017 includes 

a Joint Regulation instructing all autonomous municipalities with permitting offices to follow one set of zoning 

and construction rules regardless of the project’s location.

Conclusion PR-9

Few homeowners have flood insurance and of those that do, the majority have private flood 

insurance: Although flood insurance is available in Puerto Rico through the NFIP and private 

insurers, adoption rates are very low. The MAT literature review found that there may be as many 

as 40,000 private residential flood policies in Puerto Rico at the time of the hurricane compared to 

only 4,200 NFIP policies. Private flood insurance policies make up 90 percent of the flood policies 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 7-9

CONCLUSIONS AND RECOMMENDATIONS

in Puerto Rico versus only two percent nationwide. The MAT did not undertake a full assessment 

of insurance in Puerto Rico, but it is believed that the unique construction of the island and the 

prevalence of concrete homes allow for reduced private insurance premiums compared to NFIP 

rates. However, quality and comparison of benefits has not been studied. 

Recommendation PR-9a. FEMA should consider working with the Insurance Institute 

for Business & Home Safety (IBHS) to conduct a review of private flood insurance 

policies for equivalency and effectiveness. Private flood insurance can offer different 

protections than NFIP policies. Because Puerto Rico’s reliance on private insurance is 

unique in the U.S., a study is warranted after this event to assess the efficacy of private 

insurance on homeowners’ ability to rebuild more quickly while reducing the burden on 

U.S. taxpayers. 

Recommendation PR-9b. FEMA in conjunction with IBHS should consider developing 

materials, outreach, and partnerships to educate homeowners on flood insurance (both 

private and NFIP) options and importance. Flood insurance reimburses for covered 

building and contents coverage up to certain limits and helps the insured recover from 

flood events. Materials should include simplified handouts that outline minimum 

requirements of a recommended flood insurance policy. 

Conclusion PR-10

Administrative Order 2017-07 (OGPe 2017) exempted certain recovery efforts and essential 

activities from ordinary construction permits: Rebuilding and repair of certain infrastructure 

was exempt from construction permitting for a period of 120 days. Construction during this time 

required construction plans certified by a licensed engineer or architect.

Recommendation PR-10a. Develop a process for documentation of short-term, postdisaster repairs. OGPe should develop a process for documentation of short-term, 

post-disaster repairs. Rebuilding and repairing during the 120-day exemption period 

required a construction plan certified by a licensed engineer or architect. Documenting 

rebuilding and repairs enables retroactive review to confirm compliance with applicable 

building codes and policies. This process could be leveraged for emergency repairs, so 

that if a presidential disaster declaration is made, a database and process would be in 

place to document short-term post-disaster repairs.

Recommendation PR-10b. Develop process for retroactive permit review of rebuilding 

and repairs. OGPe should develop a process to retroactively review construction plans 

and other relevant documents for rebuilding and repairs conducted during any permit 

exemption period.
7-10 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

CONCLUSIONS AND RECOMMENDATIONS

7.3.3 Planning Regulation 13

Conclusion PR-11

Puerto Rico’s Floodplain Management Ordinance has not been coordinated with the 2018 I-Codes: 

The current Puerto Rico floodplain management ordinance and the 2009 I-Codes are reasonably 

closely-linked for floodplain management purposes. However, the current floodplain management 

ordinance no longer properly coordinates with the many changes that have been made over the 

past eight years to the 2018 I-Codes. This will result in confusion in implementing the Floodplain 

Management Ordinance and could lead to development that is not compliant with the current 

building code.

Recommendation PR-11. Integrate the update to the Puerto Rico Floodplain 

Management Ordinance with the proposed updates to the PRBC. The Puerto Rico 

Floodplain Management Ordinance should be updated and integrated with the floodresistant provisions currently included in the 2018 I-Codes proposed for adoption into 

the PBRC. This document needs to be properly integrated with IBC© Section 1612, IBC 

Appendix G, and IRC© Sections R301, R322, and R401 (and other sections), enabling 

effective compliance for all development with the flood-resistant provisions of the 

I-Codes and the NFIP. The flood-resistant provisions of the IBC© and IRC© and their 

reference standards, primarily ASCE 24, provide improved criteria for flood-resistant 

construction. The PRPB should utilize FEMA’s model floodplain ordinance to help them 

develop and adopt its own that seamlessly integrates with the I-Codes. 

7.3.4 NFIP

Conclusion PR-12

Not every community has a Certified Floodplain Manager (CFM): Puerto Rico has five NFIP 

communities that collectively include all seventy-four municipalities. Additionally, eighteen of the 

seventy-four municipalities have autonomous capabilities, including many that issue construction 

permits. The Association of State Floodplain Managers lists only six CFM certifications in Puerto 

Rico.

Recommendation PR-12. All NFIP communities and autonomous municipalities that 

actively issue construction permits should have a Certified Floodplain Manager or 

equivalent on staff. All NFIP communities and autonomous municipalities that issue 

construction permits should have at least one staff member that is a Certified Floodplain 

Manager or that holds an equivalent certification. 

Conclusion PR-13

Only a single community, Ponce, participates in the Community Rating System (CRS): The CRS 

is an incentive program that encourages communities to develop more hazard-resistant building 

practices and provides insurance discounts in communities that do. The MAT observed interest 

from municipal officials to lower the cost of flood insurance and provide additional outreach on 

flood to residents.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 7-11

CONCLUSIONS AND RECOMMENDATIONS

Recommendation PR-13a. FEMA Region II should consider providing outreach to 

Puerto Rico on the benefits of participating in the CRS. Participation in the CRS 

benefits everyone and can provide deep discounts on FEMA NFIP flood insurance. 

FEMA Region II should consider providing outreach to the communities on the benefits 

and assist in achieving this goal. 

Recommendation PR-13b. The PRPB should encourage participation in the CRS 

for communities that would benefit. The PRPB should encourage participation in 

the CRS for the communities that would most benefit, which can provide additional 

outreach on flood insurance and lower the cost of flood insurance premiums. The CRS 

recognizes community efforts beyond the NFIP minimum standards by reducing flood 

insurance premiums for policies in the community. The CRS is similar to, but separate 

from, programs from the private insurance industry that grade communities on the 

effectiveness of their fire suppression and building code enforcement. CRS discounts 

on NFIP flood insurance premiums range from 5 percent up to 45 percent, which may 

incentivize building owners to purchase flood insurance.

Conclusion PR-14

FIRMs for Puerto Rico do not delineate Coastal A Zones (CAZs): Puerto Rico’s current effective 

FIRM, dated 2009, was prepared prior to the current mapping standard. New coastal studies identify 

areas where breaking wave conditions in AE Zones are similar to but less severe than those in VE 

Zones. Laboratory tests and post-disaster investigations have shown that moderate breaking waves as 

small as 1.5 feet can cause significant structural damage if buildings are not designed to withstand 

these forces. For new coastal studies, the inland limit of these moderate wave areas, where breaking 

waves between 1.5 and 3 feet (0.5 and 0.9 meters) are expected during base flood conditions, is 

identified on the FIRM by the Limit of Moderate Wave Action (LiMWA). The CAZ is the area 

between the LiMWA and VE Zone boundary and includes requirements in the I-Codes that are 

similar to VE Zone requirements.

Recommendation PR-14. Ensure new ABFE maps and FIRMs depict LiMWA on all 

appropriate map products. The LiMWA delimits the CAZ, which includes VE Zone 

design and construction requirements in the most recent I-Codes. In a CAZ, the 2018 

I-Codes require buildings to be designed according to the VE Zone requirements (with 

exceptions for backfilled stem wall foundations, which may be allowed, depending on 

site soil conditions) unless otherwise noted by the local floodplain ordinance.

7.3.5 FEMA Technical Publications and Guidance

Conclusion PR-15

Selected FEMA Building Science technical guidance publications should be updated to incorporate 

lessons learned from the MAT: The Building Science Branch at FEMA HQ develops and maintains 

over 200 publications and resources that provide technical guidance on how to assess risk; identify 

vulnerabilities; better understand the NFIP and the regulatory environment with respect to building 

codes and standards; and provide best practices and mitigation measures that can be taken to reduce 

vulnerabilities to flood, wind, and seismic hazards. The 2017 hurricane season brought landfalling 

hurricanes to the island territories and the continental United States. There are many valuable and 
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CONCLUSIONS AND RECOMMENDATIONS

important damage observations and lessons learned from this and other events, and the observed 

damage might have been avoided if the guidance from these documents had been incorporated at 

different building locations. However, while the approaches and theory in these publications are 

still accurate, many of the building codes have been updated and may impact the current approach 

outlined in these documents.

Recommendation PR-15a. FEMA should consider translating select publications to 

Spanish. Most FEMA publications are provided only in English. To aid in the recovery of 

Puerto Rico, FEMA should consider translating key recovery documents to Spanish. 

Recommendation PR-15b. FEMA should complete Guidelines for Wind Vulnerability 

Assessments for Critical Facilities. FEMA’s Building Science Branch has been 

developing guidance to assess wind vulnerabilities of critical facilities. FEMA should 

include lessons learned from the 2017 hurricane season in finishing this publication, 

which would greatly benefit many stakeholders in the U.S.

Recommendation PR-15c. Update select FEMA Building Science Publications 

impacting coastal construction. FEMA’s Building Science Branch, in the Risk 

Management Directorate, should consider updating its key hurricane technical guidance 

publications to include lessons learned from the 2017 hurricane season and update to 

current building codes. These publications might include but not necessarily be limited 

to the following:

● FEMA P-55 Coastal Construction Manual (FEMA 2011b)

● FEMA P-499 Home Builder’s Guide to Coastal Construction (FEMA 2010b)

● FEMA P-762 Local Officials Guide for Coastal Construction (FEMA 2009)

● FEMA P-804 Wind Retrofit Guide for Residential Buildings (FEMA 2010c)

Recommendation PR-15d. Update the FEMA Risk Management Series guidance 

publications for natural hazards. FEMA’s Building Science Branch, working with other 

FEMA and DHS entities, should consider updating select technical documents from the 

FEMA Natural Hazard Risk Management Series to include lessons learned from the 

2017 hurricane season and update to current building codes. These publications might 

include but not be limited to the following:

● FEMA P-424 Design Guide for Improving School Safety in Earthquakes, Floods, 

and High Winds (FEMA 2010)

● FEMA P-543 Design Guide for Improving Critical Facility Safety from Flooding 

and High Winds (FEMA 2007a)

● FEMA P-577 Design Guide for Improving Hospital Safety in Earthquakes, 

Floods, and High Winds: Providing Protection to People and Buildings (FEMA 

2007b)
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 7-13

CONCLUSIONS AND RECOMMENDATIONS

● FEMA P-1019 Emergency Power Systems for Critical Facilities: A Best Practices

(FEMA 2014a)

7.4 Planning and Programmatic Mitigation

Conclusion PR-16

Schools have been consolidated into facilities that remain vulnerable to flood hazards: The MAT 

observed that the consolidation of schools in areas susceptible to flooding still left some schools in 

use within the SFHA. One of these consolidated school facilities was in the municipality of Toa Baja, 

which has a high flood risk.

Recommendation PR-16. The Puerto Rico Department of Education should consider 

performing a vulnerability assessment of existing buildings in planning consolidation 

of schools. Officials evaluating schools for consolidation should consider the vulnerability 

of available facilities. A program of the Puerto Rico Department of Housing currently 

exists to evaluate the vulnerability of potential shelters. In addition to that program, the 

PRDE officials should consider using the following FEMA publications to help perform 

the vulnerability assessments: Safe Rooms and Storm Shelters for Life-Safety Protection 

from Hurricanes (FEMA PR-RA3, Appendix D); Design Guide for Improving School 

Safety in Earthquakes, Floods, and High Winds (FEMA 2010); and Emergency Power 

Systems for Critical Facilities: A Best Practices Approach to Improving Reliability (FEMA 

2014).

Conclusion PR-17

Many non-compliant homes exist throughout Puerto Rico: Many buildings were constructed 

informally or without permits throughout Puerto Rico. Stakeholders have an interest in working 

with homeowners to bring existing, informally constructed homes into compliance with the building 

code.

Recommendation PR-17. Develop processes for bringing noncompliant buildings 

into compliance. OGPe should consider developing processes for retrofitting existing 

informal construction. The goal when retrofitting existing buildings should be to 

meet the hazard-resistant provisions of the most current building code and floodplain 

management ordinance requirements.

7.5 General Building Considerations

Conclusion PR-18

Windows (glazed openings) on existing buildings are vulnerable to damage and failure from wind 

pressures and wind-borne debris: Existing buildings of all types that have unprotected windows 

(glazing) on exterior walls are vulnerable to failure from wind pressures and wind-borne debris. 

When these glazed openings fail, the buildings are exposed to additional internal wind pressures 
7-14 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

CONCLUSIONS AND RECOMMENDATIONS

and the building interior also becomes exposed to the wind and rain associated with the events. 

Failures were observed in all building types visited by the MAT including homes, businesses, schools, 

and critical facilities. In some cases, failures of opening protection systems occurred due to building 

alterations that made it difficult or impossible to deploy the systems or due to lack of maintenance.

Recommendation PR-18a. Existing homeowners should consider protecting their 

windows. Existing homeowners should consider protecting their windows and glass 

doors with rated opening protection systems (i.e., storm shutters) or retrofit the home 

with impact-resistant glazing. Puerto Rico Recovery Advisory 5, Protecting Windows 

and Openings in Buildings (FEMA PR-RA5, Appendix D) provides guidance on 

the installation and protection of windows and doors. When those options are cost 

prohibitive, consider constructing and maintaining plywood panels that are cut and 

sized to cover each window or glass door at the home (per the wood panel design criteria 

for opening protection set forth in the 2018 IRC©).

Recommendation PR-18b. Existing non-residential building owners should consider 

protecting their windows. Existing non-residential building owners should consider 

protecting their windows and glass doors with rated opening protection systems (i.e., 

storm shutters) or retrofit the buildings with impact-resistant glazing. FEMA PR-RA5 

and U.S. Virgin Islands (USVI) Recovery Advisory 4, Design, Installation, and Retrofit of 

Doors, Windows, and Shutters (FEMA 2018d) provide guidance on the installation and 

protection of windows and doors.

Recommendation PR-18c. Existing critical facility owners and operators should 

protect their windows. Existing critical facility owners and operators should protect their 

windows and glass doors with rated opening protection systems (i.e., storm shutters) or 

retrofit the buildings with impact-resistant glazing. Perform a vulnerability assessment 

as described in the general recommendations section. FEMA PR-RA5 and FEMA USVIRA4 provide guidance on the installation and protection of windows and doors.

Recommendation PR-18d. Building owners should consider developing a life-cycle 

management program for roof coverings, rooftop equipment restraints, and opening 

protection systems. The life-cycle management program should include periodic 

maintenance and should test deployment of opening protection systems as well as 

assessments of rooftop coverings and rooftop equipment attachments.

Conclusion PR-19

Water intrusion was prevalent through existing windows (glazed openings) and metal panel 

jalousie systems: Water infiltration into buildings at glazed openings, and specifically through 

metal panel jalousie systems, was observed throughout Puerto Rico. Metal panel jalousies were the 

least effective in keeping wind-driven rain and water out of buildings. This issue was observed in 

most building types visited by the MAT, including homes, businesses, schools and critical facilities.

Recommendation PR-19. Improve performance of windows and openings to resist 

water intrusion and windborne debris through glazed openings. When using jalousie 

window systems, consider the use of flood/water resistant materials within the occupied 

space where these jalousie windows are used. Where conditioned space exists behind 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 7-15

CONCLUSIONS AND RECOMMENDATIONS

the window system, consider use of impact-resistant glazing or glazed openings that are 

protected with impact-resistant (opening protection) systems such as shutters. Note, 

opening protection systems are not rated to reduce water intrusion for the windows and 

openings they protect. 

Conclusion PR-20

Water intrusion was prevalent through existing doors: The MAT observed extensive water intrusion 

through existing doors. Existing doors did not prevent wind-driven rain intrusion and weatherstripping was often not present. 

Recommendation PR-20. Limit water intrusion through doors by design and mitigation. 

For new construction, building owners should consider constructing a vestibule using 

flood/water resistant materials. For existing construction, building owners should 

consider retrofitting the building with weather-stripping to reduce water intrusion. 

Puerto Rico Recovery Advisory 5, Protecting Windows and Openings in Buildings 

(Appendix D) and USVI Recovery Advisory 4, Design, Installation, and Retrofit of 

Doors, Windows, and Shutters (FEMA 2018d) provide guidance on the installation and 

protection of windows and doors.

Conclusion PR-21

OGPe does not provide a list of specific design criteria for design professionals to include on 

construction drawings: The IBC© and IRC© provide some guidance for minimal information 

that should be included on construction documents to clarify and verify design information and 

criteria. However, the minimum guidance provide in the code is much less than requirements set 

forth in other areas prone to hurricanes, for example, by many county building departments in 

South Florida. 

Recommendation PR-21. OGPe should consider requiring specific notes and design 

criteria for hazard-resistant design of a structure, including seismic design loads, 

and require load path connections to be shown. To implement and enforce the new 

codes, OGPe staff charged with permitting, plan review and inspections should require 

a complete list of the flood, wind, and seismic design criteria used for the home or 

building. The design professional responsible for the design and construction of new 

residential buildings (as well as repairs to existing buildings) should be made aware 

of the high seismic design criteria for Puerto Rico. In the permitting process, OGPe 

should ensure the design professional checks wind loads against seismic loads; these 

are dependent upon the site condition, the geometry of the house and foundation, 

and the weight of materials used for construction. In addition, the notes and design 

criteria should include testing information related to debris impact protection systems 

for glazing, water intrusion, flood-resistant materials, corrosion-resistant materials, and 

other performance-based building components. 
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CONCLUSIONS AND RECOMMENDATIONS

Conclusion PR-22

Tile roofs resulted in poor performance: The MAT observed poor performance of tile roofs 

throughout Puerto Rico. Roof tiles often became windborne debris and resulted in damage to 

nearby buildings due to poor attachments and connections.

Recommendation PR-22. Existing tile roofs should be evaluated for proper anchorage 

and connectors. Tile roofs, when improperly attached, are often a source of windborne 

debris. Existing tile roofs should be evaluated against ASCE 7-16 standards to ensure 

compliance with the updated components and cladding wind pressures1. 

Conclusion PR-23

Building Utilities are at risk of flood damage: The MAT observed many building utilities below 

the BFE or at ground level where they are susceptible to flood damage. When building utilities 

were elevated, they were elevated to various heights, sometimes not high enough. Locating utility 

connections and meters above flood levels limited flood damage. 

Recommendation PR-23. Building owners should elevate critical systems whenever 

possible. Building owners should follow P-348, Protecting Building Utility Systems from 

Flood Damage. This approach could limit damage and enable quicker reoccupation. 

Additional resources include Hurricane Isaac Recovery Advisory 2, Minimizing Flood 

Damage to Electrical Service Components (FEMA 2012).

7.6 Residential and Low-Rise Buildings

Conclusion PR-24

Lack of roof deck (sheathing) under roof panel coverings resulted in increased damage: The MAT 

observed homes with metal panel roof coverings that performed poorly and resulted in the loss of 

roof panels during the storms. In most cases, these homes did not have a wood deck beneath the 

metal panels. The absence of a wood deck resulted in a lack of adequate anchorage for the panels, 

reduced stability in the roof structure, and full exposure of the building interior when the metal 

panels were lost. 

Recommendation PR-24. Require the use of wood deck on wood-framed roofs below 

any roof covering. For new and existing homes, if calculations are not submitted to show 

the open wood frame does not require wood decking to provide lateral support, OGPe 

should consider requiring the use of wood structural panels or board to provide stability, 

load path, and a solid roof deck beneath the roof covering to comply with design 

requirements. See Puerto Rico Recovery Advisory 6, Repair and Replacement of Wood 

Residential Roof Covering Systems (FEMA PR-RA6, Appendix D) for guidance on how 

1The FEMA Mitigation Assessment Team Report: Hurricane Charley in Florida (FEMA 2005) provides information 

on tile roof installation methods.
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CONCLUSIONS AND RECOMMENDATIONS

to create a structural system beneath the roof covering and to establish a load path from 

metal covering all the way down to foundation. 

Conclusion PR-25

Even homes that were undamaged during the hurricanes may be susceptible to future wind and 

seismic events: The MAT observed many homes that experienced little to no structural damage 

but remain vulnerable to the effects of high winds. In most cases, the connections between the 

structural members and a lack of protection for glazed openings are the weakest links in the load 

path and are vulnerable to failure. 

Recommendation PR-25. Homeowners should consider evaluating and retrofitting 

existing homes for wind and seismic vulnerabilities. Homeowners should consider 

hiring design professionals to evaluate the existing roof structure to determine if can 

carry at least 75 percent of the design load. If it cannot, they should consider performing 

wind retrofits with continuous load path systems in accordance with Repair and 

Replacement of Wood Residential Roof Covering Systems (FEMA PR-RA6, Appendix D) 

and Wind Retrofit Guide for Residential Buildings (FEMA 2010). Homeowners can also 

consider wind retrofit techniques set forth for the different protection levels of FEMA 

P-804 to holistically improve the hazard resistance of homes.

Conclusion PR-26

Roof Penetrations often caused water intrusion: Where roof penetrations existed, such as at utility 

service masts, localized roof failure and water intrusion often occurred.

Recommendation PR-26. Avoid rooftop penetrations whenever possible. Do not 

penetrate the roof whenever possible whenever attaching rooftop equipment. Consider 

use of design guidance found in Rooftop Equipment Maintenance and Attachment in 

High-Wind Regions (FEMA PR-RA1, Appendix D) when attaching rooftop equipment or 

service utility masts.

Conclusion PR-27

It is common practice to use prescriptive home designs in residential construction and permitted 

by the building code: The MAT obtained prescriptive design plans developed by the Commonwealth 

of Puerto Rico by PRDOH and from municipalities around the island. The designs included many 

hazard-resistant design approaches developed in response to Hurricane Georges in 1998 and 

provided details to allow a homeowner or contractor to successfully construct a home compliant 

with the 1997 UBC, which had been adopted after Hurricane Georges. 

However, availability and access to the plans may have been limited, and no formal program was 

identified that supported the distribution and use of these designs. Where residential construction 

appeared to perform well, the homes had many of the features observed in the prescriptive designs, 

but the homes could not be verified as having been constructed to the prescriptive plans. 
7-18 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

CONCLUSIONS AND RECOMMENDATIONS

Recommendation PR-27. OGPe, with support from stakeholders, should develop 

prescriptive design plans and make them available to support affordable, codecompliant construction of homes and residential buildings. Providing prescriptive 

home designs based upon the new 2018 I-Codes through a government program 

would provide an opportunity to address the informal construction issue in Puerto 

Rico. Currently, FEMA is supporting OGPe with the development of a select number 

of prescriptive designs for single-family homes. OGPe should consider developing a 

program using the design plans under development to address roofing, structural, and 

building envelope issues in a holistic approach to wind- and multi-hazard mitigation of 

new homes and existing homes. 

7.7 Schools, Hospitals, Public Buildings, 

and Other Mid-Rise Buildings 

Conclusion PR-28

Many buildings flooded because their main floor levels are too low on the site: Several schools, fire 

stations, and other critical facilities were damaged as localized flooding occurred at the building 

site (this occurred even at sites where the mapped flood hazard area was identified as Zone X). 

Although individual site conditions led to the localized flooding, in many cases, had the elevation of 

the main or first floor of these buildings been constructed several inches higher than the adjacent 

grade, the flood damage to the facilities would have been mitigated.

Recommendation PR-28. Elevate main (primary) floors of buildings above adjacent 

grade. Designers and contractors should provide a differential of at least 8 inches between 

the top of the finished floor elevation of the main (primary) floor and the surrounding 

grade. As a best practice, buildings should be built with the finished floor elevated above 

surrounding grade. A common practice is to make the grade difference one stair height 

or 8 inches above grade at its lowest point. Local practice may call for this elevation to be 

higher or lower. This allows easy accommodation for access and egress by use of a single 

stair, ramp, or pad. 

Conclusion PR-29

Internal pressures were not adequately addressed through open/louvered window assemblies: 

Many multi-use and athletic (gymnasium) facilities with long-span roofs were damaged during the 

hurricanes. While the larger, structural members of the MWFRS did not fail, intermediate structural 

members (purlins), roof decking, roof coverings, and exterior wall systems were all observed to have 

failed, apparently from pressurization of the building.

Recommendation PR-29a. Designers must consider and adequately address internal 

wind pressures. For new construction, and for repairs to existing buildings, use of 

louvered openings that allow free passage of air into facilities, especially in long-span 

buildings, must properly account for and address internal wind pressures and the effects 

they have on building components. 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 7-19

CONCLUSIONS AND RECOMMENDATIONS

Recommendation PR-29b. Consider retrofitting glazed openings, windows, and 

doors of existing buildings for current wind design pressures and wind-borne debris 

protection. Owners of existing buildings should consider retrofitting glazed openings, 

windows, and doors to comply with wind pressure, wind-driven rain, and debris-impact 

protection requirements of ASCE 7-16. This will help ensure the building maintains a 

secure envelope, reducing wind pressures on the building. It will also tend to reduce 

damage from water intrusion and wind-driven rain. 

Conclusion PR-30

Insufficient maintenance of roof coverings resulted in increased damage: Many of the schools and 

public buildings observed by the MAT had roof coverings and roof systems that were not maintained 

or were past their useful life. When impacted by the storms, these roof systems failed even though 

the roof decks supporting them did not, resulting in significant damage or loss of function for the 

facilities. Further, when roof coverings did remain in place, roofs at hospitals, public buildings, and 

schools were often punctured by wind-borne debris. 

Recommendation PR-30a. Regularly assess, adequately maintain, and repair or 

replace roofs when needed. Building owners and operators (both public and private) 

should develop maintenance programs for their building exteriors, specifically for 

roof coverings and roof systems. Much of the damage and loss of function for schools 

and critical facilities, including hospitals, could have been limited or avoided if roof 

coverings were properly installed, maintained, and replaced when worn out. The 

maintenance programs should include a section to address punctures of the roof 

coverings (membranes, systems, etc.) for when roof coverings remain in place but are 

damaged.

Recommendation PR-30b. Avoid the use of single-ply roof membranes. Avoid the 

use of single-ply roof membranes for critical facilities; these systems are vulnerable to 

puncture, tearing, and blow-off. 

Conclusion PR-31

Debris that damaged roof coverings were often from the building itself: The MAT observed at 

several locations that the debris that punctured roof coverings at both hospitals, several schools, 

and some public buildings was likely generated from the building itself. This led to water intrusion 

even when the roof covering remained in place. 

Recommendation PR-31. Adequately anchor HVAC and other equipment to roofs.

Design professionals and building managers should adequately anchor HVAC systems to 

resist high wind loads; this applies to both new and existing buildings and equipment. 

Puerto Rico Recovery Advisory 2, Rooftop Equipment Maintenance and Attachment 

in High-Wind Regions (FEMA PR-RA2, Appendix D) provides guidance for anchoring 

HVAC and other equipment to the roof, roof structure, or parapets. FEMA P-543 and 

FEMA 577 provide guidance for equipment attachment in high winds at critical facilities 

and hospitals, respectively. If the equipment cannot be adequately mounted on the roof, 

then consideration should be given to moving the equipment elsewhere on-site. 
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CONCLUSIONS AND RECOMMENDATIONS

Conclusion PR-32

Building systems, including backup power generators, switches, and equipment, should be 

protected against wind, wind-borne debris and flood: Where building systems were properly 

protected from wind forces and wind-borne debris, these systems were able to maintain backup 

and emergency power during the events. However, this was not the case at all critical facilities. In 

many critical facilities, generator failures were observed due to failures from wind-borne debris 

penetration or damaged equipment due to wind.

Recommendation PR-32. Protect building systems to requirements of ASCE 7 

and ASCE 24. Once vulnerabilities have been identified, design building systems in 

accordance with ASCE 7-16 and ASCE 24-14. Refer to FEMA P-1019 and Puerto Rico 

Recovery Advisory 1, Rooftop Equipment Attachment and Maintenance in High-Wind 

Regions (FEMA PR-RA1, Appendix D) for guidance. 

Conclusion PR-33

Failure of equipment penthouses and elevator equipment vents on roofs caused loss of operations: 

The MAT observed the failure of rooftop equipment, penthouses and vent structures that resulted 

in impacts to mechanical systems that caused building loss of important operational functions.

Recommendation PR-33a. Design mechanical penthouses and equipment housing to 

resist high winds. In new construction and critical facilities, mechanical penthouses and 

equipment houses should be designed to withstand loss of operation due to high winds. 

These features should be designed per ASCE 7-16 to resist high wind loads.

Recommendation PR-33b. Retrofit mechanical penthouses and equipment housing 

in existing buildings. Building owners and operators should perform vulnerability 

assessments of their facilities to identify vulnerabilities to wind hazards. FEMA P-424 

(schools), FEMA P-543 (critical facilities), and FEMA 577 (hospitals) provide use-specific 

guidance for performing vulnerability assessments for flood, wind, and seismic hazards. 

Once vulnerabilities have been identified, mitigation to secure rooftop equipment 

should be designed per ASCE 7-16 wind load requirements.

7.8 Shelters

Conclusion PR-34

The PRDOH shelter program is helpful but has shortcomings. The PRDOH manages and maintains 

a robust system to evaluate facilities to be used as “event-specific” shelters and post-event shelters. 

However, the MAT observed that the designated structures do not meet FEMA P-361 standards for 

life-safety protection. During severe weather, building occupants should utilize the location in the 

building that is least susceptible to collapse or failure. Buildings used as “shelters” before, during, 

and after the hurricanes were not evaluated by design professionals using a consistent methodology 

or program to identify vulnerabilities from damage or failure from flood, wind or seismic forces. 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 7-21

CONCLUSIONS AND RECOMMENDATIONS

Recommendation PR-34a. PRDOH should consider updating the shelter program 

in accordance with FEMA guidance. This program should be based on the FEMA 

guidance for safe rooms (P-361), P-424, P-431, and Safe Rooms and Storm Shelters for 

Life-Safety Protection from Hurricanes (FEMA PR-RA3, Appendix D).

Recommendation PR-34b. FEMA should work with PRDOH to improve the evaluation 

form for the PRDOH shelter program. The PRDOH form used to identify and evaluate 

potential shelters records operational information that is useful for PRDOH, PRDE, and 

PREMA; however, additional information should be collected. All of the 383 currentlyidentified event-specific shelters are constructed of reinforced concrete and located 

outside of special flood hazard areas (mapped flood zones), but these two important 

criteria do not yet appear on the evaluation form. Also, more information related to 

backup power systems and structural and envelope hardening and protection should be 

collected.

Conclusion PR-35

The MAT observed no shelters designed in accordance with FEMA P-361 or ICC 500© for 

protection for residents during hurricanes: Due to its island geography, Puerto Rico has limited 

ability to evacuate residents from the path of hurricanes and tropical storms, especially those that 

rapidly intensify or change direction. Safe rooms and storm shelters designed to the criteria of FEMA 

P-361 or the ICC 500© are needed to provide purpose-built structures to protect residents when 

these storms impact the islands. Storm shelters and their associated design criteria are identified 

and defined in the IBC©; however, they are not currently required to be constructed in Puerto Rico. 

There are no public safe rooms or storm shelters in Puerto Rico that have been constructed to the 

criteria of FEMA P-361 or the ICC 500©. 

Recommendation PR-35a. Require specific educational and first responder facilities 

to provide a storm shelter. Safe rooms and storm shelters provide buildings or portions 

of buildings that have been designed and constructed to provide life-safety protection 

from high wind events such as hurricanes. Puerto Rico should create a local amendment 

to the PRBC to require that any new facilities constructed for Educational Group E 

Occupancies with an aggregate occupant load of 50 or more (including public and 

private schools, but excluding Group E day-care facilities or Group E occupancies 

accessory to places of religious worship), 911 call stations, emergency operations centers 

and fire, rescue, ambulance and police stations comply with IBC table 1604.5 as a Risk 

Category IV structure and be provided with a storm shelter constructed in accordance 

with ICC 500©. In addition, OGPe and PRDOH should keep a record of all ICCcompliant community shelters in the Commonwealth.

Recommendation PR-35b. Federally funded grantors for safe rooms, such as HUD, 

should consider requiring that FEMA 361 criteria be met. Where storm shelters are 

being constructed with federal funding, the flood-resistant construction criteria and 

safe room operational guidance provided in FEMA P-361 should be considered and 

implemented in addition to the requirements of the ICC 500©.

Recommendation PR-35c. Encourage residents to build in-residence storm shelters. 

The IBC© and IRC© also provide the design criteria for in-residence storm shelters 
7-22 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

CONCLUSIONS AND RECOMMENDATIONS

by referencing the ICC 500©. Encourage residents who want to construct a place in 

their homes to shelter in place during a hurricane to request a permit and construct 

in-residence storm shelters. FEMA has developed prescriptive design and construction 

plans (in FEMA P-320 Taking Shelter from the Storm [FEMA 2014c]) to construct a safe 

room in or near a home or small business that comply with the design criteria of ICC 

500©.

Recommendation PR-35d. Encourage municipalities and residents to create a system 

for identifying and tracking residential safe room and storm shelter locations. After 

a high wind event, trees or debris may fall on shelters, trapping people inside. In 

addition, communication may be limited. Registering shelters and safe rooms, allows the 

emergency responders to check the status of residents and rescue survivors as needed. 

Ensure that OGPe and the local municipalities keep a record of all residential safe rooms 

and storm shelters in the Commonwealth.

7.9 Siting

Conclusion PR-36

Topography increased wind speeds throughout mountainous areas of Puerto Rico. The MAT 

observed the effects of topography on the wind speeds across the islands. Many locations were 

observed to have experienced higher wind speeds due to channeling of the wind through the 

mountains. Designing for these effects involves using a prescriptive method for estimating wind 

speed-up in ASCE 7 (incorporated by referenced into the IBC©). To improve performance of 

buildings in the portions of the island where wind speed-up occurs, better design guidance and 

outreach are needed. Most locations impacted by wind speed-up did not appear to have hardened 

buildings to resist the higher wind speeds. 

Recommendation PR-36. Develop new design guidance for wind speed-up in Puerto 

Rico. Puerto Rico should develop and include guidance on topographic effects in 

the PRBC. The ongoing study to produce special wind hazard maps would provide a 

simplified approach for designers to address wind speed-up appropriately in building 

design. When this guidance is complete, it should be adopted into the PRBC and 

proposed for incorporation into the next edition of ASCE 7.

Conclusion PR-37

Many buildings were observed in highly vulnerable locations: Homes were observed in locations 

including steep slopes and sited directly over streams. These homes are at very high risk of damage 

or destruction from natural hazards. These buildings were extremely vulnerable to landslide and 

other slope stability hazards. 

Recommendation PR-37a. Puerto Rico and local municipalities should consider 

acquisition of highly vulnerable buildings. Acquisition of buildings in highly vulnerable 

locations including floodways, unstable slopes, and eroding coastlines should be 

prioritized.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 7-23

CONCLUSIONS AND RECOMMENDATIONS

Recommendation PR-37b. FEMA and the USGS should consider development of 

enhanced guidance for addressing slope stability and erosion vulnerabilities for new 

and existing construction. Enhance guidance could include maps, fact sheets and 

flowcharts to address vulnerabilities.

Recommendation PR-37c. OGPe should require documentation of geotechnical review 

for areas with slope stability concerns. Include documentation of geotechnical review 

in areas with slope stability concerns.

Recommendation PR-37d. OGPe should require erosion vulnerability assessment for 

new construction in known erosion hazard areas. Include documentation of erosion 

vulnerability assessment for permits in areas with known erosion impacts.

7.10 Solar Heating and PV Systems

Conclusion PR-38

Ground-mounted PV systems heavily damaged by the storm hindered the full return of electrical 

utility service: In specific cases, catastrophic failure of ground-mounted, grid-connected PV solar 

facilities impacted the restoration of power to residents. Some of the systems provided a substantial 

proportion of the energy portfolio on their respective islands, and damage limited overall island 

production. This forced a greater reliance on fuel imports and daily fuel shipments observed 

following the storms. For homeowners reliant on the utility grid, the damage to PV facilities may 

have affected the restoration time and/or price of their power supply.

Recommendation PR-38. Incorporate mitigation and preparedness aspects into PV 

system repairs. Incorporate mitigation and preparedness best practices into groundmounted PV solar facilities connected to the utility grid.

Conclusion PR-39

Structural performance may have been impacted by incorrect sizing: Damage ranging from 

significant to catastrophic failure were observed at ground-mounted PV solar arrays due to potential 

incorrect sizing. The degree and type of failures typically were caused by load path discontinuity and 

indicated that structural support systems, clips, and other connections were inadequately designed 

for the magnitude and cyclical loading anticipated of the high wind events.

Recommendation PR-39. Improve the sizing of structural systems for ground-mounted 

PV solar arrays. When designing ground-mounted PV solar arrays, engineers should 

consider the design wind speeds that inform other building types on the islands and 

size members and connections appropriately to withstand the proper magnitudes 

and cyclical loading regimes. Generally, stronger structural systems were needed at 

numerous facilities, and can be achieved in a variety of ways through a comprehensive 

design process with reference to appropriate related standards. 
7-24 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

CONCLUSIONS AND RECOMMENDATIONS

Conclusion PR-40

Open cross-section framing members do not have the same performance as closed cross-section 

members due to differences in member strength and torsional rigidity: In a comparison between 

multiple ground-mounted PV solar arrays on the islands, structural systems that featured similarlysized framing members performed significantly better when they utilized closed sections instead of 

open sections in their designs. Members such as C-section beams did not provide adequate torsional 

strength when exposed to high wind events and the cyclical loading and flutter associated with 

them. Sections that had closed ovular or rectangular shapes provided more robust resistance and 

allowed for a consistent transfer of loads throughout the rest of the system. 

Recommendation PR-40. Use closed shape cross-sections for the design of structural 

framing members. Designs for ground-mounted PV solar arrays should consider the 

use of closed ovular or rectangular section framing members instead of open section 

members to provide the necessary torsional resistance required to withstand the unique 

wind loads exerted by high speed wind events.

Conclusion PR-41

Installation of arrays does not allow for bolt checks: The current installation procedures for groundmounted PV solar arrays do not include specifications for the torque levels of bolted connections. 

An observed array that included this procedure experienced only minor damage to and loosening 

of bolt connections, which bolstered the continuity of the load path. Similarly, annual torque 

checks and checks following high wind events are not provided for after construction. These checks 

ensure that bolts remain at the proper necessary torque levels despite the inevitable loosening of 

connections from dynamic loading over time. 

Recommendation PR-41. Ground-mounted PV solar installation and O&M procedures 

should account for proper bolt torque specifications and checks. Upon installation, all 

bolted connections should be tightened and checked for the appropriate level of torque 

as specified by the design requirements for high speed wind events. These torque levels 

should be, at minimum, checked annually and following high wind events. Any loose 

connections should be tightened accordingly to ensure adequate design performance. 

Conclusion PR-42

Vibrations from dynamic, cyclical loading caused failure of bolted connections of ground-mounted 

PV solar arrays: The high wind loads experienced by the framing systems for ground-mounted PV 

solar arrays caused nuts to back out of their bolt connections. This resulted in the failure of the 

connection and a discontinuity in the system’s load path. Without connections in place, framing 

members and attached PV panels are easily lifted from their bases by high speed winds and further 

damaged. One observed array performed notably well except where bolts backed out and caused 

such weakness. This system did not have any type of locking mechanism to prevent back-cycling of 

the connector.

Recommendation PR-42. Designers should consider utilizing a stainless-steel locking 

nut with a nylon insert for all bolted structural connections of ground-mounted PV 

solar arrays. Any bolted connections that support the wind loads of the framing system 
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 7-25

CONCLUSIONS AND RECOMMENDATIONS

should include a stainless-steel locking nut with a nylon insert to prevent back-cycling. 

These nuts provide resistance to the vibrations caused by dynamic wind loading and will 

not significantly loosen during a high wind event.

Conclusion PR-43

Current design standards for ground-mount PV solar arrays do not provide for dynamic testing: 

Design standards specified by entities such as UL and FM Global do not include dynamic wind load 

testing in their standards development. Much of the damage observed in Puerto Rico to groundmounted PV solar arrays resulted in part from the cyclical loading of dynamic wind loads. Without 

further research into the necessary design criteria for such impacts, engineers and owners will lack 

the detailed performance-based standards necessary to ensure the adequacy of their systems to realworld events. 

Recommendation PR-43. Consider research into dynamic testing of ground-mount 

PV solar arrays. Standards developers, system manufacturers, and university- and 

government-based researchers should consider further research into the effects of 

dynamic testing on structural performance. Wind-tunnel-based research will allow 

investigation into how connections are loosened over time and structural members fail 

under conditions more correlated to actual storm events.

Conclusion PR-44

Current design standards do not provide recommended design loads specific to ground-mount 

PV solar arrays: ASCE 7-16 and the Structural Engineers Association of California Wind Design 

for Solar Arrays (SEAOC PV2 2017) specify design wind loads and procedures for rooftop PV solar 

arrays but do not provide similar guidance for ground-mount PV solar arrays. The overall lack of 

design criteria available for ground-mount PV solar arrays furthered the variable performance of 

systems in Puerto Rico and brings up questions over the ability of new systems to withstand high 

wind events. Following Hurricanes Irma and Maria, the lack of guidance for designers became 

evident through the multiple means of failure observed across the islands. This indicated that 

incomplete design standards were not limited to a single area of focus. 

Recommendation PR-44. ASCE should consider adding specific design criteria for 

ground-mount PV solar arrays to ASCE 7-22. New and appropriate design standards 

for ground-mount PV solar arrays in ASCE 7-22 could be referenced by SEAOC PV2, the 

I-Codes, and the Puerto Rico Building Code to provide for more consistent performance 

of such systems in high wind events. Any new standards would require the focused 

coordination of researchers, industry professionals, and code officials to ensure that 

such criteria are adequate without being overly prescriptive.

Conclusion PR-45

Current design standards do not clearly provide recommended design loads specific to solar water 

heaters: ASCE 7-16 and the Structural Engineers Association of California Wind Design for Solar 

Arrays (SEAOC PV2 2017) specify design wind loads and procedures for rooftop PV solar arrays but 

do not provide clear guidance for rooftop solar water heaters. 
7-26 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

CONCLUSIONS AND RECOMMENDATIONS

Recommendation PR-45. ASCE should consider adding specific design criteria for 

solar water heaters to ASCE 7-22. At a minimum, ASCE should provide guidance in 

the ASCE 7 Commentary (e.g., C29.4.3) on applying solar panel criteria to solar water 

heaters. Appropriate design standards for solar water heaters in ASCE 7-22 could be 

referenced by SEAOC PV2, the I-Codes, and the Puerto Rico Building Code to provide 

for more consistent performance of such systems in high wind events. Any new standards 

would require the focused coordination of researchers, industry professionals, and code 

officials to ensure that such criteria are adequate without being overly prescriptive.

7.11 Flood-Damage-Resistant Materials

Conclusion PR-46

The use of flood-damage-resistant materials minimized damage due to water intrusion and 

flooding and facilitated quicker recovery: The MAT observed reoccupation of concrete and CMU 

buildings that were subjected to flood depths exceeding 2 feet (0.6 meters) or that experienced 

water intrusion through openings including jalousie windows. 

Recommendation PR-46. Building owners should use flood-damage-resistant materials 

in existing concrete and CMU buildings. This approach could limit damage and 

enable quicker recovery. Building owners may refer to Puerto Rico Recovery Advisory 

4, Best Practices for Minimizing Flood Damage to Existing Structures (FEMA PRRA4, Appendix D) and NFIP Technical Bulletin 2, Flood Damage-Resistant Materials 

Requirements (FEMA 2008a) for guidance.

7.12 Summary of Conclusions and Recommendations

Table 7-1 summarizes the conclusions and recommendations presented in chapter 7 and 

categorizes them according to their Recovery Support Function under the National Disaster 

Recovery Framework2. Categories include Community Planning and Capacity Building (CPCB), 

Economic, Health and Social Services (HSS), Housing, Infrastructure Systems, and Natural and 

Cultural Resources. Additionally, FEMA has launched a sector-based approach to recovery in 

Puerto Rico to prioritize critical issues and allow for targeted planning3. The table categorizes 

conclusions and recommendations with respect to these sectors, which include Housing, Energy, 

Water, Transportation, HSS, Public Buildings, Communications, Economic, Capacity Building, and 

Natural and Cultural Resources.

2For more information on the Recovery Support Functions, see https://www.fema.gov/recovery-support-functions

3For more information on the sector-based approach, see https://www.fema.gov/news-release/2018/03/16/sixmonths-after-maria-progress-made-work-continues
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 7-27

CONCLUSIONS AND RECOMMENDATIONS

 Supporting 

Observations Conclusions Recommendations NDRF Recovery Support Function

Sector-Based 

Approach for 

Puerto Rico

Sections 

3.4.1, 3.4.4, 

4.4.1 and 

4.4.3

PR-1 – Many of the 

damaged buildings 

observed lacked a 

continuous load path.

PR-1a. OGPe should review 

and publish prescriptive 

design guidance and load 

path details for designers and 

contractors.

PR-1b. OGPe should require 

construction documents to list 

critical design parameters and 

show load path connections.

CPCB, Housing Capacity Building, 

Housing

Sections 6.6 PR-2–Many building 

owners had limited 

awareness of hurricane 

hazard risks and 

vulnerabilities.

PR-2. Facility and building 

owners should consider 

performing vulnerability 

assessments for all relevant 

hazards prior to the natural 

hazard event.

CPCB, Housing, HSS Capacity Building, 

Housing, HSS

Sections 2.1 

and 2.2

PR-3–The PRBC can 

be updated to higher 

standards.

PR-3a. OGPe should finalize 

the adoption of the latest 

hazard-resistant building 

codes and standards.

PR-3b. OGPe should review 

and update the PRBCs 

hazard-resistant building

codes and standards 

according to a recurring code 

update cycle. 

CPCB Capacity Building

Sections 

3.4.3, 3.4.4, 

4.4.1. 4.4.3, 

4.4.4, 5.1.2 

and 7.2.2

PR-4–Corrosion 

of fasteners and 

connectors contributed 

to building failures 

throughout Puerto Rico. 

PR-4. OGPe should develop a 

local amendment to the PRBC 

requiring corrosion-resistant 

materials.

CPCB Capacity Building

Section 3.3.1 PR-5–Staged 

construction remains 

unnecessarily exposed 

to the elements, 

degrading exposed 

structural elements over 

time.

PR-5a. Protect material during 

staged construction.

PR-5b. Limit extended open 

permit periods for staged or 

phased construction.

Housing

CPCB

Housing

Capacity Building

Table 7-1: Table of Conclusions and Recommendations
7-28 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

CONCLUSIONS AND RECOMMENDATIONS

 Supporting 

Observations Conclusions Recommendations NDRF Recovery Support Function

Sector-Based 

Approach for 

Puerto Rico

Sections 

2.3.2, and 

2.3.3

PR-6–OGPe lacks 

adequate staffing, which 

has affected hazardresistant design and 

impacted its ability 

to enforce the latest 

building codes and 

standards.

PR-6a. OGPe should consider 

hiring additional code 

enforcement staff.

PR-6b. The PRPB, 

OGPe, and autonomous 

municipalities should consider 

evaluating plan review staffing 

and guidance.

PR-6c. Municipalities should 

consider participating in the 

Insurance Service Office’s 

(ISO) Building Codes 

Effectiveness Grading 

Schedule (BCEGS).

CPCB

CPCB

CPCB

Capacity Building

Capacity Building, 

Municipalities

Capacity Building, 

Municipalities

Sections 

2.3.2 and 

2.3.3

PR-7–Training was 

insufficient for code 

enforcement staff and 

in-house technical 

experts.

PR-7. OGPe should train 

building code enforcement 

staff on Puerto Rico building 

code and local amendments.

CPCB Capacity Building

Sections 

2.3.3 and 

2.3.4

PR-8–Professional 

licensure and training 

positively affected 

quality.

PR-8a. Establish a licensure 

program for contractors in 

Puerto Rico.

PR-8b. Train design 

professionals and contractors 

on the latest hazard-resistant 

design and construction 

techniques and best practices.

PR-8c. Establish public 

database of actively licensed 

and registered design 

professionals and contractors.

CPCB

CPCB, Housing

CPCB, Housing

Capacity Building

Capacity Building, 

Housing

Capacity Building, 

Housing

Section 2.4 PR-9–Few homeowners 

have flood insurance 

and of those that do, the 

majority have private 

flood insurance.

PR-9a. FEMA should consider 

working with the Insurance 

Institute for Business & Home 

Safety to conduct a review 

of private flood insurance 

policies for equivalency and 

effectiveness. 

PR-9b. FEMA in conjunction 

with IBHS should consider 

developing materials, 

outreach, and partnerships 

to educate homeowners on 

flood insurance (both private 

and NFIP) options and 

importance.

CPCB, Housing Capacity Building, 

Housing
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 7-29

CONCLUSIONS AND RECOMMENDATIONS

 Supporting 

Observations Conclusions Recommendations NDRF Recovery Support Function

Sector-Based 

Approach for 

Puerto Rico

Section 2.3.4 PR-10–Administrative 

Order 2017-07 (OGPe 

2017-07) exempted 

certain recovery 

efforts and essential 

activities from ordinary 

construction permits. 

PR-10a. Develop process for 

documentation of short-term, 

post-disaster repairs.

PR-10b. Develop process for 

retroactive permit review of 

rebuilding and repairs.

CPCB Capacity Building

Section 2.2 

and 3.2.1

PR-11–Puerto Rico’s 

Floodplain Management 

Ordinance has not been 

coordinated with the 

2018 I-Codes.

PR-11. Integrate the update 

to the Puerto Rico Floodplain 

Management Ordinance with

the proposed updates to the 

PBRC.

CPCB Capacity Building

Section 2.3.3 PR-12–Not every 

community has a 

Certified Floodplain 

Manager.

All NFIP communities 

and autonomous 

municipalities

that actively issues 

construction permits 

should have a Certified 

Floodplain Manager or 

equivalent on staff. 

CPCB Capacity Building

Section 2.4 PR-13–Only a single 

community, Ponce, 

participates in the 

Community Rating 

System (CRS).

PR-13a. FEMA Region II 

should consider providing 

outreach to Puerto Rico on 

the benefits of participating in 

CRS.

PR-13b. The PRPB should 

encourage participation in 

the CRS for communities that 

would benefit.

CPCB Capacity Building, 

Municipalities

Sections 2.3 

and 3.2.1

PR-14–FIRMs for 

Puerto Rico do not 

delineate Coastal A

Zones.

PR-15–Selected FEMA

Building Science 

technical guidance 

publications should be 

updated to incorporate 

lessons learned from 

the MAT.

PR-14. Ensure new ABFE 

maps and FIRMs depict 

LiMWA on all map products.

PR-15a. FEMA should 

consider translating select 

publications to Spanish.

PR-15b. FEMA should 

complete Guidelines for Wind 

Vulnerability Assessments for

Critical Facilities.

PR-15c. Update select 

FEMA Building Science 

Publications impacting coastal 

construction.

PR-15d. Update the FEMA

Risk Management Series 

guidance publications for 

natural hazards

CPCB

Housing, HSS

Housing, HSS

Housing, HSS

Housing, HSS

Capacity Building

Housing, HSS

Housing, HSS

Housing, HSS

Housing, HSS
7-30 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

CONCLUSIONS AND RECOMMENDATIONS

 Supporting 

Observations Conclusions Recommendations NDRF Recovery Support Function

Sector-Based 

Approach for 

Puerto Rico

Section 4.2.1 PR-16–Schools have 

been consolidated into 

facilities that remain 

vulnerable to flood risks/

hazards.

PR-16. The Department of 

Education should consider 

performing a vulnerability 

assessment of existing 

buildings in planning 

consolidation of schools.

HSS Education, HSS

Sections 

2.3.4 and 3.5

PR-17–Many noncompliant homes are 

present throughout 

Puerto Rico

PR-17. Develop process 

for bringing non-compliant 

buildings into compliance.

CPCB, Housing Capacity Building, 

Housing

Sections 

3.4.3 and 

4.4.2

PR-18–Windows 

(glazed openings) on 

existing buildings are 

vulnerable to damage 

and failure from wind 

pressures and windborne debris.

PR-18a. Existing homeowners 

should consider protecting 

their windows.

PR-18b. Existing nonresidential building owners 

should consider protecting 

their windows.

PR-18c. Existing critical 

facilities owners and operators 

should consider protecting 

windows.

Housing

HSS

HSS

Capacity Building, 

Housing

Capacity Building, 

HSS

Capacity Building, 

HSS

Sections 

3.4.3, 4.4.2, 

5.1.2, 5.2.2, 

5.3.2 and 

5.5.2

PR-19–Water intrusion 

was prevalent through 

existing windows 

(glazed openings) and 

metal panel jalousie 

systems.

PR-19. Improve performance 

of windows and openings 

to resist water intrusion and 

windborne debris through 

glazed openings.

Housing, HSS Housing, HSS, 

Public Buildings

Sections 

3.4.3 and 

5.4.2

PR-20–Water intrusion 

was prevalent through 

existing doors.

PR-20. Limit water intrusion 

through doors by design and 

mitigation.

Housing, HSS Housing, HSS, 

Public Buildings

Section 2.3.4 PR-21-OGPe does 

not provide a list of 

design criteria for 

design professionals to 

include on construction 

drawings.

PR-21. OGPe should consider 

requiring specific notes and 

design criteria in hazardresistant design of a structure, 

including seismic design 

loads, and to show load path 

connections.

CPCB Capacity Building

Sections 

3.4.4, 3.5.3, 

4.4.3 and 

7.1.1

PR-22–Tile roofs 

resulted in poor 

performance.

PR-22. Existing tile roofs 

should be evaluated for 

proper anchorage and 

connectors.

Housing, HSS Housing, HSS

Sections 

3.3.3 and 

4.3.2

PR-23–Building utilities 

are at risk of flood 

damage.

PR-23. Building owners 

should elevate critical systems 

whenever possible.

Housing, HSS Housing, HSS, 

Public Buildings

Sections 

3.4.1 and 

3.4.4

PR-24–Lack of roof 

deck (sheathing) under 

roof panel coverings 

resulted in increased 

PR-24. Require the use of 

wood deck on wood-framed 

roofs below any roof covering.

Housing Housing

damage.
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 7-31

CONCLUSIONS AND RECOMMENDATIONS

 Supporting 

Observations Conclusions Recommendations NDRF Recovery Support Function

Sector-Based 

Approach for 

Puerto Rico

Section 3.4.1 PR-25–Even homes 

that were undamaged 

during the hurricanes 

may be susceptible to 

future wind and seismic 

events.

PR-25. Homeowners 

should consider evaluating 

and retrofitting existing 

homes for wind and seismic 

vulnerabilities.

Housing Housing

Section 5.4.2 PR-26–Roof 

penetrations often 

caused water intrusion.

PR-26. Avoid rooftop 

penetrations whenever 

possible.

HSS HSS

Section 1.3.2 PR-27–It is common 

practice to use 

prescriptive home 

designs in residential 

construction and 

permitted by the 

building code.

PR-27. OGPe, with the 

support from stakeholders, 

should develop prescriptive 

design plans and make 

them available to support 

affordable, code-compliant 

construction of homes and 

residential buildings.

Housing, HSS, 

Infrastructure

Capacity Building, 

Housing

Section 4.3.1 PR-28–Buildings flood 

because their main floor 

levels are too low on 

the site. 

PR-28. Elevate main (primary) 

floors of buildings above 

adjacent grade.

HSS HSS

Section 3.4.3 

and 4.4.2

PR-29–Internal 

pressures were not 

adequately addressed 

through open/louvered 

window assemblies.

PR-29a. Designers must 

consider and adequately 

address internal wind 

pressures. 

PR-29b. Consider retrofitting 

glazed openings, windows, 

and doors of existing buildings 

for current wind design 

pressures and windborne 

debris protection.

Housing, HSS HSS

Sections 

3.4.4, 4.4.1, 

4.4.3, 4.4.4, 

5.1.2 and 

5.2.2

PR-30–Insufficient 

maintenance of roof 

coverings resulted in 

increased damage.

PR-30a. Regularly assess, 

adequately maintain, and 

repair or replace roofs when 

needed.

PR-30b. Avoid the use of 

single-ply roof membranes. 

Housing, HSS Housing, HSS

Section 4.4.4 PR-31–Debris that 

damaged roof coverings 

were often from the 

building itself.

PR-31. Adequately anchor 

HVAC and other equipment to 

roofs.

HSS HSS

Sections 

4.3.2, 5.1.3, 

5.2.5 and 

5.3.5

PR-32–Backup power 

generators, switches, 

and equipment should 

be protected against 

wind, wind-borne 

debris, and flood.

PR-32. Protect backup 

and emergency generator 

systems and equipment to 

requirements of ASCE 7. 

HSS HSS, Public 

Buildings
7-32 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

CONCLUSIONS AND RECOMMENDATIONS

 Supporting 

Observations Conclusions Recommendations NDRF Recovery Support Function

Sector-Based 

Approach for 

Puerto Rico

Section 5.2.4 PR-33–Failure of 

equipment penthouses 

and elevator equipment 

vents on roofs caused 

loss of operations.

PR-33a. Design mechanical 

penthouses and equipment 

housing to resist high winds.

PR-33b. Retrofit mechanical 

penthouses and equipment 

housing in existing buildings.

HSS HSS

Sections 

4.5.1 and 

4.5.2

PR-34–PRDV shelter 

program helpful but has 

shortcomings.

PR-34a. PRDV should 

consider an update of the 

shelter program in accordance 

with FEMA guidance.

PR-34b. FEMA should work 

with PRDV to improve the 

evaluation form for PRDV 

shelter program.

CPCB, HSS Capacity Building, 

Education, HSS, 

Public Buildings

Sections 

4.5.1, 4.5.2 

and 4.6

PR-35–There are no 

safe rooms designed in 

accordance with FEMA

P-361 or storm shelters 

designed in accordance 

with ICC 500 for 

protection for residents 

during hurricanes.

PR-35a. Require specific 

educational and first 

responder facilities to provide 

a storm shelter.

PR-35b. Federally funded 

grantors for safe rooms, such 

as HUD, should consider 

requiring that FEMA 361 

criteria be met. 

PR-35c. Encourage residents 

to build in-residence storm 

shelters.

PR-35d. Encourage 

municipalities and residents to

create a system for identifying 

and tracking residential

safe room and storm shelter 

locations. 

HSS

HSS

Housing

Housing

Education, HSS, 

Public Buildings

Education, HSS, 

Public Buildings

Education, HSS, 

Public Buildings

Education, 

Housing, Public 

Buildings

Chapter 4 PR-36 – Topography 

increased wind

speeds throughout

mountainous areas of 

Puerto Rico. 

PR-36– Develop new design 

guidance for wind speed-up

in Puerto Rico.

CPCB Capacity Building
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT 7-33

CONCLUSIONS AND RECOMMENDATIONS

 Supporting 

Observations Conclusions Recommendations NDRF Recovery Support Function

Sector-Based 

Approach for 

Puerto Rico

Section 3.2.1 

and 3.2.2

PR-37–Many buildings 

were observed in highly 

vulnerable locations.

PR-37a. Puerto Rico and 

local municipalities should 

consider acquisition of highly 

vulnerable buildings.

PR-37b. FEMA and the USGS 

should consider development 

of enhanced guidance for 

addressing slope stability and 

erosion vulnerabilities for new 

and existing construction.

PR-37c. Require 

documentation of geotechnical 

review for areas with slope 

stability concerns.

PR-37d. Require erosion 

vulnerability assessment for 

new construction in known 

erosion areas.

Housing

Housing

CPCB

CPCB

Housing

Housing

Capacity Building

Capacity Building

Section 6.5 PR-38–Groundmounted PV systems 

heavily damaged by the 

storm hindered the full 

return of electrical utility 

service.

PR-38. Incorporate mitigation 

and preparedness aspects 

into PV system repairs

Infrastructure Energy

Section 6.5.1 PR-39–Structural 

performance may have 

been impacted by 

incorrect sizing.

PR-39. Improve the sizing of 

structural systems for groundmounted PV solar arrays.

Infrastructure Energy

Section 6.1.1 PR-40–Open crosssection framing 

members do not have 

the same performance 

as closed cross-section 

members due to 

differences in member 

strength and torsional 

rigidity.

PR-40. Use closed shape 

cross-sections for the 

design of structural framing 

members.

Infrastructure Energy

PR-41–Installation of 

arrays does not allow 

for bolt checks.

PR-41. Ground-mounted 

PV solar installation and 

O&M procedures should 

account for proper bolt torque 

specifications and checks.

Infrastructure Energy

Sections 

6.5.1 and 

6.5.2

PR-42–Vibrations 

from dynamic, cyclical 

loading caused failure 

of bolted connections 

of ground-mounted PV 

solar arrays.

PR-42. Designers should 

consider utilizing a stainlesssteel locking nut with a nylon 

insert for all bolted structural 

connections of groundmounted PV solar arrays.

Infrastructure Energy
7-34 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

CONCLUSIONS AND RECOMMENDATIONS

 Supporting 

Observations Conclusions Recommendations NDRF Recovery Support Function

Sector-Based 

Approach for 

Puerto Rico

Section 2.5 PR-43–Current design 

standards for groundmounted PV solar 

arrays do not provide 

for dynamic testing.

PR-43. Consider research into 

dynamic testing of groundmount PV solar arrays.

Infrastructure Capacity Building, 

Energy

Section 2.5 PR-44–Current design 

standards do not 

provide recommended 

design loads specific 

to ground-mounted PV 

solar arrays.

PR-44. ASCE should consider 

adding specific design criteria 

for ground-mount PV solar 

arrays to ASCE 7-22.

Infrastructure Capacity Building, 

Energy

Section 3.3.1 PR-45–Current design 

standards do not clearly 

provide recommended 

design loads specific to 

solar water heaters.

PR-45. ASCE should consider 

adding specific design criteria 

for solar water heaters to 

ASCE 7-22.

Housing Housing

Section 3.3.1 PR-46-The use of 

flood-damage-resistant

materials minimized

damage due to water 

intrusion and flooding 

and facilitated quicker 

recovery.

PR-46. Building 

owners should use 

flood-damage-resistant

materials in existing 

concrete and CMU 

buildings.

Housing Housing
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT A-1

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HURRICANES

IRMA AND MARIA

IN PUERTO RICO

MITIGATION ASSESSMENT TEAM REPORT

Acknowledgments

The Federal Emergency Management Agency (FEMA) would like to acknowledge the contributions 

of the following persons to the Mitigation Assessment Team study of the areas affected by Hurricanes 

Irma and Maria in Puerto Rico:

Glenn Bethel

USDA Remote Sensing Advisor

Bill Blanton, CFM

FEMA Headquarters

Clark Brewer

FEMA Region II

Sarah Caponigro, PE

Atkins

Bill Coulbourne, PhD, PE 

Bill Coulbourne Consulting

Hector Cruzado, PhD, PE

Department of Civil and Environmental Engineering and Land Surveying, Polytechnic 

University of Puerto Rico.

Gina Filippone

AECOM
Kelly George, CFM

DCMC Partners

Gerardo Irizarry

Municipality of Carolina

Víctor Joglar

Municipality of Bayamón

José Lebrón, CFM

FEMA Region II

Betito Marquez

Municipality of Toa Baja

Victor Medina

Puerto Rico Planning Board

Julio Menéndez

PRDOH

Judith Mitrani-Reiser, PhD

National Institute of Standards and Technology

Mike Moriarty

FEMA Region II

Evelyn Moya

OGPe

Carlos Olmedo 

Municipality of Toa Baja

Gustavo Pacheco, PhD, PE

Department of Civil and Environmental Engineering and Land Surveying, Polytechnic 

University of Puerto Rico

Manny A. Perotin, PE, CFM

CDM Smith

John “Bud” Plisich

FEMA Region IV

Miguel Rivera

Puerto Rico Planning Board

Arleen Reyes Rodriguez, CFM

Puerto Rico Planning Board

Laurie Schoeman

Enterprise Community Partners

Ian Carlo Serna

OPGe

A-2 MITIGATION ASSESSMENT TEAM REPORT HURRICANES IRMA AND MARIA IN PUERTO RICO

ACKNOWLEDGMENTS
Pataya Scott

FEMA Headquarters

Alan Springett

FEMA Region II

Sandra Torres

Municipality of Bayamón

José L. Valenzuela, MSEM, CFM

Puerto Rico Central Recovery, Reconstruction, and Resiliency Office (COR3)

Cristobal Vazquez

Municipality of Toa Baja

Peter Vickery, PhD

ARA

Gregory Wilson, CFM

FEMA Headquarters

Alexis Xavier Estrada-Cora

FEMA 

Erica Kuligowski, PhD

National Institute of Standards and Technology

Carmen Martinez

National Institute of Standards and Technology

Héctor González

FEMA Headquarters

Gokhan Inci, PhD, PE, PMP

FEMA Headquarters

Carmen Quiñones

Municipality of Carolina

Carlos Rodríguez

Municipality of Carolina

Lisette Rodríguez

OGPe

HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT A-3

ACKNOWLEDGMENTS
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U.S. Department of Energy. 2017. Hurricane Irma & Hurricane Harvey Event Report (Update #22).

Event Report. https://www.energy.gov/sites/prod/files/2017/10/f37/Hurricane%20

Harvey%20Event%20Summary%2022.pdf

Zimmer Biomet. 2017. “Zimmer Biomet Provides Update on Manufacturing Facilities in Guaynabo 

and Ponce, Puerto Rico”. October 4. http://investor.zimmerbiomet.com/news-and-events/

news/2017/10-04-2017

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BIBLIOGRAPHY
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Acronyms

ABFE Advisory Base Flood Elevation

AC Air conditioning

ARA Applied Research Associates, Inc.

ARPE Administración de Reglamentos y Permisos (Regulations and Permits Administration)

ARRA American Recovery and Reinvestment Act

ASCE American Society of Civil Engineers

AST Atlantic Standard Time

ASTM American Section of the International Association for Testing Materials, now ASTM 

International

BARA Best available refuge area

BCEGS Building Code Effectiveness Grading Schedule

BFE Base Flood Elevation 

BPAT Building Performance Assessment Team

CAZ Coastal A Zone

CIAPR Colegio de Ingenieros y Agrimensores de Puerto Rico (Professional College of 

Engineers and Land Surveyors of Puerto Rico)

CMU Concrete masonry unit
C-2 MITIGATION ASSESSMENT TEAM REPORT HURRICANE IRMA AND MARIA IN PUERTO RICO

ACRONYMS

CPCB Community Planning and Capacity Building

CRS Community Rating System

DFE Design flood elevation

DHSOIG Department of Homeland Security Office of the Inspector General

EOC Emergency Operations Center

FEMA Federal Emergency Management Agency

FIRM Flood Insurance Rate Map

HMA Hazard Mitigation Assistance

HMGP Hazard Mitigation Grant Program

HSS Housing and Social Services

HPRP Home Protection Roofing Program

HUD Housing and Urban Development

HVAC Heating, ventilation, and air conditioning

I-Codes International Code series

IBC International Building Code

IBHS Insurance Institute for Business and Home Safety

ICBO International Conference of Building Officials

ICC International Code Council

IEBC International Existing Building Code

IRC International Residential Code

JFO Joint Field Office

kph kilometers per hour

MAT Mitigation Assessment Team

MBS Metal Building System

MEP Mechanical, electrical, and plumbing

MHHW Mean high high water

mph miles per hour

MW Megawatts

MWFRS Main wind-force resisting system

MWh megawatt hours

NFIP National Flood Insurance Program
HURRICANES IRMA AND MARIA IN PUERTO RICO MITIGATION ASSESSMENT TEAM REPORT C-3

ACRONYMS

NIST National Institute of Standards and Technology

NOAA National Oceanographic and Atmospheric Administration

NSHP New Secure Housing Program

NSSA National Storm Shelter Association

OGPe Oficina de Gerencia de Permisos (Permits Management Office)

ORNL Oak Ridge National Laboratory

PRBC Puerto Rico Building Code

PRDE Puerto Rico Department of Education (Departamento de Educación)

PRDOH Puerto Rico Department of Housing (Departamento de Vivienda)

PRDJ Puerto Rico Department of Justice (Departamento de Justicia de Puerto Rico)

PREMA Puerto Rico Emergency Management Agency, formally the Puerto Rico State Agency for 

Emergency and Disaster Management (Agencia Estatal para el Manejo de Emergencias y 

Administración de Desastres)

PREPA Puerto Rico Electric Power Authority (Autoridad de Energía Eléctrica)

PRIFA Puerto Rican Infrastructure Financing Authority (Autoridad para el financiamiento de 

la Infraestructura)

PRPB Puerto Rico Planning Board (Junta de Planificación de Puerto Rico)

PV Photovoltaic

SEAOC Structural Engineers Association of California

SST Sea surface temperature

UBC Uniform Building Code

UL UL LLC, formerly Underwriters Laboratories

UPR University of Puerto Rico

USACE U.S. Army Corps of Engineers

USGS U.S. Geological Survey

USVI U.S. Virgin Islands

WAP Weatherization Assistance Program
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Recovery Advisories for 

Hurricanes Irma and Maria in 

Puerto Rico

FEMA has prepared new Recovery Advisories (RAs) that present guidance to engineers, architects, 

homeowners, and local officials on mitigation measures that can be taken to minimize building 

damage in a hurricane event. Five advisories are referenced in this Appendix:

PR - RA 1: Rooftop Equipment Maintenance and Attachment in High-Wind Regions

PR - RA 2: Siting, Design, and Construction in Coastal Flood Zones

PR - RA 3: Safe Rooms and Storm Shelters for Life-Safety Protection from Hurricanes

PR - RA 4: Best Practices for Minimizing Flood Damage to Existing Structures

PR - RA 5: Protecting Windows and Openings in Buildings

PR - RA 6: Repair and Replacement of Wood Residential Roof Covering Systems

These advisories are online at https://www.fema.gov/media-library/assets/documents/158123
FEMA P-2020