National Flood Insurance Program (NFIP) 

Floodplain Management Bulletin 

Historic Structures 

FEMA P-467-2 

May 2008 

FEMA 
National Flood Insurance Program 

Page 1 of 22 

Floodplain Management Bulletin 

Historic Structures 

This Floodplain Management Bulletin addresses how the National Flood Insurance Program (NFIP) 

treats historic structures. This bulletin also identifies mitigation measures that can be taken to protect 

historic structures from floods. The bulletin addresses the following topics: 

Introduction ...........................................................................................................................................2 

Background on the NFIP.......................................................................................................................2 

The NFIP and Historic Structures .........................................................................................................3 

Definition of “Historic Structures” .................................................................................................3 

Floodplain Management Requirements that Provide Relief for Historic Structures ......................4 

Historic Structures in the Floodway......................................................................................................5 

New Construction and Non-contributing Structures in Historic Districts.............................................6 

Substantial Improvements to Existing Structures in Historic Districts .................................................7 

Flood Insurance for Historic Structures ................................................................................................8 

Minimizing the Impacts of Flooding on Historic Structures.................................................................9 

Protection Measures for Historic Structures ...................................................................................9

Hazard Mitigation Planning Can Benefit Historic Structures.......................................................19 

Further Information .............................................................................................................................20 

State and Local Mitigation Planning “How-To” Guides ..............................................................20 

Other Mitigation Documents ........................................................................................................21 

Comments............................................................................................................................................22 

Ordering Information ..........................................................................................................................22 
National Flood Insurance Program Floodplain Management Bulletin 

Page 2 of 22 

Introduction 

The National Flood Insurance Program (NFIP) gives special consideration to the unique value of 

one of our Nation’s most significant resources – its historic buildings, landmarks, and sites. It does 

so in two ways. 

First, the NFIP floodplain management regulations provide significant relief to historic structures. 

Historic structures do not have to meet the floodplain management requirements of the program as 

long as they maintain their historic structure designation. They do not have to meet the new 

construction, substantial improvement, or substantial damage requirements of the program. This 

exclusion from these requirements serves as an incentive for property owners to maintain the 

historic character of the designated structure (44 CFR §60.3). It may also serve as an incentive for 

an owner to obtain historic designation of a structure. 

Secondly, a designated historic structure can obtain the benefit of subsidized flood insurance 

through the NFIP even if it has been substantially improved or substantially damaged so long as the 

building maintains its historic designation. The amount of insurance premium charged the historic 

structure may be considerably less than what the NFIP would charge a new non-elevated structure 

built at the same level. Congress requires that the NFIP charge actuarial rates for all new 

construction and substantially improved structures (National Flood Insurance Act of 1968, 

42 U.S.C. 4015). 

Although the NFIP provides relief to historic structures from having to comply with NFIP floodplain management requirements for new construction, communities and owners of historic 

structures should give consideration to mitigation measures that can reduce the impacts of flooding 

on historic structures located in Special Flood Hazard Areas (44 CFR §60.3). Mitigation measures 

to minimize future flood damages should be considered when historic structures are rehabilitated or 

are repaired following a flood or other hazard event. Qualified professionals such as architects, 

historic architects, and engineers who have experience in flood mitigation techniques can help 

identify measures that can be taken to minimize the impacts of flooding on a historic structure 

while maintaining the structure’s historic designation. 

The purpose of this floodplain management bulletin is to explain how the NFIP defines historic 

structure and how it gives relief to historic structures from NFIP floodplain management requirements (44 CFR §60.3). This bulletin also provides guidance on mitigation measures that can be 

taken to minimize the devastating effects of flooding to historic structures. 

Background on the NFIP 

Congress created the NFIP in 1968 to provide federally supported flood insurance coverage, which 

generally was not available from private companies. The NFIP is based on a mutual agreement 

with communities that have been identified as having Special Flood Hazard Areas. The Federal 

Emergency Management Agency (FEMA) will make flood insurance coverage available in a 
National Flood Insurance Program Floodplain Management Bulletin 

Page 3 of 22 

community provided that it adopts and enforces floodplain management regulations that meet or 

exceed the minimum requirements of the NFIP (44 CFR §60.3). This is accomplished through 

local floodplain management regulations. 

The NFIP minimum building and development regulations that communities must adopt require 

that new and substantially improved and substantially damaged residential buildings be elevated so 

that the lowest floor is at or above the Base Flood Elevation (BFE) determined for the site. Nonresidential buildings have the option of elevation or dry floodproofing to the BFE [44 CFR 

§60.3(c)(2), (c)(3), and (e)(4)]. Dry floodproofing means making a building watertight, substantially impermeable to floodwaters to the BFE. 

Substantial improvement means “any reconstruction, rehabilitation, addition, or other improvement of a structure, the cost of which equals or exceeds 50 percent of the market value of the 

structure before the “start of construction” of the improvement. This term includes structures 

which have incurred substantial damage regardless of the actual repair work performed.” 

Substantial improvement also includes the repair of buildings that have been substantially 

damaged. Substantial damage means “damage of any origin sustained by a structure whereby the 

cost of restoring the structure to its before damaged condition would equal or exceed 50 percent of 

the market value of the structure before the damage occurred.” 

In summary, structures that are “substantially improved” and “substantially damaged” must be 

brought into compliance with the community’s floodplain management requirements [44 CFR 

§60.3(c)(2), (c)(3), and (e)(4)]. 

The NFIP and Historic Structures 

This section provides information on the NFIP definition of “historic structure” and the floodplain 

management requirements that will be included in community floodplain management ordinances. 

Definition of “Historic Structures” 

The definition section of the NFIP [Code of Federal Regulations (CFR) 44 Part 59], defines 

“historic structure” as “any structure that is: 

(1) Listed individually in the National Register of Historic Places (a listing maintained by the 

Department of Interior) or preliminarily determined by the Secretary of the Interior as 

meeting the requirements for individual listing on the National Register; (This includes 

structures that are determined to be eligible for listing by the Secretary of the Interior as a 

historic structure. A determination of “eligibility” is a decision by the Department of the 

Interior that a district, site, building, structure or object meets the National Register criteria 

for evaluation although the property is not formally listed in the National Register.)
National Flood Insurance Program Floodplain Management Bulletin 

Page 4 of 22 

(2) Certified or preliminarily determined by the Secretary of the Interior as contributing to the 

historical significance of a registered historic district or a district preliminarily determined 

by the Secretary to qualify as a registered historic district; 

(3) Individually listed on a state inventory of historic places in states with historic preservation 

programs which have been approved by the Secretary of the Interior; or 

(4) Individually listed on a local inventory of historic places in communities with historic 

preservation programs that have been certified either: 

(a) By an approved state program as determined by the Secretary of the Interior or 

(b) Directly by the Secretary of the Interior in States without approved programs.”

This definition was coordinated with the Department of Interior when it was added to the NFIP 

Regulations in 1989. 

The purpose of this definition is to provide NFIP communities with criteria to distinguish between 

“historic structures” and the other existing buildings which remain subject to NFIP floodplain 

management requirements (44 CFR §60.3). While it is important to preserve historic structures and 

other cultural resources, it is also critical to ensure that other existing flood-prone structures are 

protected from flood damage when they are substantially improved or substantially damaged. 

Floodplain Management Requirements that Provide 

Relief for Historic Structures 

The NFIP floodplain management requirements contain two provisions that are intended to provide 

relief for “historic structures” located in Special Flood Hazard Areas: 

(1) The definition of “substantial improvement” at 44 CFR 59.1 includes the following exclusion for historic structures, 

 “Any alteration of a “historic structure”, provided that the alteration will 

not preclude the structure’s continued designation as an “historic structure”. 

The same exemption also applies to “historic structures” that have been “substantially damaged”. 

This provision exempts historic structures from the substantial improvement and substantial 

damage requirements of the NFIP. 

(2) The other provision of the NFIP floodplain management regulations that provides relief for 

“historic structures” is the variance criteria at 44 CFR 60.6(a). This provision states: 

 “Variances may be issued for the repair or rehabilitation of historic structures upon a determination that the proposed repair or rehabilitation will not 

preclude the structure’s continued designation as a historic structure and the 

variance is the minimum necessary to preserve the historic character and design of the structure.” 

Under the variance criteria, communities can place conditions to make the building more flood 

resistant and minimize flood damages, but such conditions should not affect the historic
National Flood Insurance Program Floodplain Management Bulletin 

Page 5 of 22 

character and design of the building. See the section on Minimizing the Impacts of Flooding 

on Historic Structures for ideas on conditions that could be established to make the building 

more flood resistant and to minimize flood damages. 

 

Communities have the option of using either provision for addressing the unique needs of “historic 

structures”. Communities should adopt only one option to address “historic structures.” Some 

communities have chosen to adopt an ordinance that requires variances for improvements or repairs 

to “historic structures” and do not exclude such improvements from the substantial improvement 

definition in their ordinance. Other communities include the “historic structures” exemption as part 

of their “substantial improvement” definition. In either case, “historic structures” can be excluded 

from the NFIP elevation and floodproofing requirements. Whether a community exempts a 

“historic structure” under the substantial improvement definition or through the variance process, 

the exemption of the “historic structure” from the NFIP floodplain management requirements 

should be documented and maintained in the community permit files. 

However, if plans to substantially improve a “historic structure” or repair a substantially damaged 

“historic structure” would result in loss of its designation as an “historic structure”, the structure no 

longer qualifies for the exemption and would be required to meet the NFIP floodplain management 

regulations (44 CFR §60.3). This determination needs to be made in advance of issuing a permit. 

This provides an incentive to the property owner to maintain the structure’s historic designation 

rather than altering the structure in such a way that it loses its designation as a “historic structure”. 

Even if a “historic structure” is exempted from the substantial improvement and substantial damage 

requirements, consideration should be given to mitigation measures that can reduce the impacts of 

future flooding. There are mitigation measures that can reduce flood damages to historic structures 

without affecting the structure’s historic designation. See the section on Minimizing the Impacts of 

Flooding on Historic Structures. 

Historic buildings may also be subject to the local building codes. Many States and communities 

use the International Codes as the basis for their buildings codes. The International Codes contain 

provisions for addressing historic buildings in a manner consistent with the NFIP. 

Historic Structures in the Floodway 

The NFIP floodplain management requirements could apply to an addition to a “historic structure”, 

if the structure or addition is located in a floodway. The floodway includes the channel of the river 

and the adjacent floodplain that must be reserved in an unobstructed condition in order to discharge 

the base flood without increasing flood levels by more than one foot (44 CFR § 59.1, “regulatory 

floodway”). All structures and improvements to structures, including additions to “historic 

structures”, must comply with the floodway encroachment provisions of 44 CFR § 60.3(c)(10) and 

(d)(3) of the NFIP Regulations. 
National Flood Insurance Program Floodplain Management Bulletin 

Page 6 of 22 

44 CFR § 60.3(c)(10) applies to rivers and streams where FEMA has established BFEs, but has not 

provided the community with the data necessary to designate a floodway: 

Require until a regulatory floodway is designated, that no new construction, 

substantial improvements, or other development (including fill) shall be permitted within Zones A1-30 and AE on the community’s FIRM [Flood Insurance Rate Map], unless it is demonstrated that the cumulative effect of the 

proposed development, when combined with all other existing and anticipated development, will not increase the water surface elevation of the base 

flood more than one foot at any point within the community. 

§ 60.3(d)(3) applies to rivers and streams where FEMA has provided both established BFEs and 

provided the community with the data necessary to designate a floodway: 

Prohibit encroachments, including fill, new construction, substantial improvements, and other development within the adopted regulatory floodway 

unless it has been demonstrated through hydrologic and hydraulic analyses 

performed in accordance with standard engineering practice that the proposed encroachment would not result in any increase in flood levels within 

the community during the occurrence of the base flood discharge. 

As an example, an addition, or any portion thereof, to a “historic structure” that expands the square 

footage of the structure beyond its footprint into the floodway must comply with the regulatory 

floodway criteria [44 CFR §60.3(c)(10) and (d)(3)]. These additions can obstruct flood flows and 

increase flood stages. Under 44 CFR § 60.3(d)(3), such an addition would be prohibited if any rise 

in the flood level would result from the addition. FEMA defines “any” as meaning a zero increase. 

New Construction and Non-contributing 

Structures in Historic Districts 

Generally, registered historic districts contain a mix of buildings. In addition to structures that 

contribute to the historic significance of the district, there will generally be structures in historic 

districts that have no historical significance and which do not contribute to the historic significance 

of a registered historic district (called “non-contributing” structures). In addition, there may be 

sites in these districts that are undeveloped or vacant land. Whole districts cannot be exempt from 

floodplain management regulations and a blanket variance cannot be issued for all land within these 

districts. The non-contributing structures and vacant lots in historic districts remain subject to all 

of the floodplain management requirements that apply to new construction and substantial 

improvements (44 CFR §60.3). 

Some communities have argued that they should be allowed to grant variances for new buildings or 

for substantial improvements to non-contributing buildings in historic districts. They claim that 

requiring that the new structures or substantially improved structures be elevated to BFE could be 

harmful to the historic significance of the district. FEMA maintains that this would be contrary to 

the purposes of the NFIP and could result in greatly increased flood damages and, in some instance, 
National Flood Insurance Program Floodplain Management Bulletin 

Page 7 of 22 

even result in loss of life. There are ways to elevate or floodproof new structures and substantially 

improve non-contributing structures so that they comply with the NFIP regulations, but that are still 

in harmony with the historic nature of the district. While the NFIP requires protection to the BFE, 

it does not specify the means (44 CFR §60.3). An architect should be able to design a new building 

that is both compliant with NFIP floodplain management requirements and compatible with the 

historic nature of the district. For example, the protection does not have to be achieved by unsightly 

mounds of dirt or bare pilings or other elevated foundations. The structure could be elevated on 

pilings or other foundation elements and the lower area then covered by an architecturally pleasing 

façade that will not impair the aesthetics of a historic district. The foundation could be camouflaged with landscaping, porches, or staircases (See the examples in latter sections of this bulletin). 

The NFIP was specifically established by Congress to reduce threats to lives and the potential for 

damages to new construction in flood hazard areas in exchange for providing flood insurance. 

Exempting new construction from the NFIP elevation requirements in historic districts would be 

contrary to the National Flood Insurance Act of 1968, as amended, and it would create a significant 

flood risk to structures and to the health and safety of the population. Potentially thousands of 

buildings would be placed in harms way, if new or non-contributing structures are not protected. 

Substantial Improvements to Existing 

Structures in Historic Districts 

Some property owners have wanted to substantially improve a non-contributing structure in a 

historic district, so that it can become a contributing structure to the historical significance of the 

registered historic district. For example, this type of improvement could involve removal of 

modern additions to the building, replacement of modern siding or roofing materials with historic 

materials, and other actions to restore the historic nature of the structure. If the improvement is a 

substantial improvement to a non-contributing structure, the structure still could qualify for relief 

from the NFIP floodplain management requirements in the following ways (44 CFR §60.3): 

• The property owner could apply through their State Historic Preservation Officer or Tribal 

Historic Preservation Officer for contributing status for the structure as is, prior to any improvements. If the building qualifies as “contributing to the historical significance of a registered historic district”, the community can grant a variance or exclude the improvements 

from the NFIP substantial improvement requirement depending on which provision the 

community has adopted [44 CFR §60.3(c)(2), (c)(3), and (e)(4)]. 

• The property owner could undertake the minimum work necessary to make the building a 

contributing structure, as long as the work is less than a substantial improvement. Once the 

structure is designated as “contributing”, any additional improvements including a substantial improvement could qualify for relief from the NFIP floodplain management requirements, so long as those improvements do not interfere with the designation as “contributing 

to the historical significance of a registered historic district” (44 CFR §60.3). 

• If the property owner chooses to undertake a substantial improvement of the building all at 

once or the owner needs to undertake the substantial improvement in order for the building 
National Flood Insurance Program Floodplain Management Bulletin 

Page 8 of 22 

to qualify as “contributing to the historical significance of a registered historic district”, the 

owner should contact the community for guidance on how they might qualify for relief from 

the NFIP substantial improvement requirement [44 CFR §60.3(c)(2), (c)(3), and (e)(4)]. In 

this situation, the community would have to issue a variance from the floodplain management ordinance. The community should obtain documentation for assurance that the improvements being proposed would qualify the building for “contributing” status before 

signing off on permits that would grant them relief under the NFIP. The owner should seek 

guidance from their State Historic Preservation Officer or Tribal Historic Preservation Officer on proposed improvements and on what documentation is needed to obtain preliminary 

approval. This information should be shared with the community. 

In all cases, the property owner should discuss their proposed plans with the community and seek 

guidance from the State Historic Preservation Officer or Tribal Historic Preservation Officer before 

undertaking any improvements to make sure the proposed work would qualify the building for the 

designation as a contributing structure. For any of the options described above, the community 

should also encourage the property owner to undertake flood damage reduction measures as part of 

the improvement, as long as measures do not interfere with its designation as a “historic structure”. 

Flood Insurance for Historic Structures 

In addition to the relief from the NFIP floodplain management requirements described above, 

owners of “historic structures” can obtain and maintain flood insurance at subsidized rates. Flood 

insurance coverage is required for most mortgage loans and for obtaining Federal grants and other 

financial assistance. The ability to obtain flood insurance coverage is also important to ensuring 

that historic structures can be repaired and restored after a flood event. 

The National Flood Insurance Act of 1968, as amended, requires that FEMA charge actuarial rates 

reflecting the flood risk to buildings built or substantially improved on or after the effective date of 

the initial Flood Insurance Rate Map (FIRM) for the community or after December 31, 1974, 

whichever is later. Actuarial rating assures that the risks associated with buildings in flood prone 

areas are borne by those located in such areas and not by the taxpayers at large. These buildings are 

referred to as Post-FIRM. The NFIP flood insurance rates are based on the degree of the flood risk. 

The flood insurance premium calculations take into account a number of factors including the flood 

risk zone shown on the FIRM, elevation of the lowest floor above or below the BFE, the type of 

building, the number of floors, and the existence of a basement or an enclosure. The NFIP 

floodplain management requirements not only are designed to protect buildings constructed in 

floodplains from flood damages; they also help keep flood insurance premiums affordable (44 CFR 

§60.3). Buildings not properly elevated will be charged a much higher flood insurance premium 

due to the increased flood risk. If substantially improved historic structures were not elevated and 

made subject to these rates, the annual insurance premiums could be many thousands of dollars a 

year. Allowing historic structures to continue to be insured at subsidized rates, even when they are 

substantially improved or substantially damaged, represents a significant financial benefit to these 

building owners. 
National Flood Insurance Program Floodplain Management Bulletin 

Page 9 of 22 

Flood insurance at subsidized rates is available whether the “historic structure” is exempt from the 

NFIP substantial improvement requirement or is granted a variance under the variance provision. 

“Historic structures” are considered Pre-FIRM under the NFIP and are charged subsidized rates 

similar to existing structures. As long as a historic structure meets the definition of “historic 

structure” under the NFIP, it will not be actuarially rated (44 CFR §59.1). 

If a “historic structure” is substantially improved such that it loses its historic designation without 

meeting the elevation requirements of the NFIP, it will be actuarially rated as a Post-FIRM 

structure. This can be significantly higher than the subsidized rate on a “historic structure.” Thus, 

the subsidized flood insurance rate on “historic structures” also serves as an incentive to maintain 

the historic designation of the structure. 

Property owners of historic structures are encouraged to purchase NFIP flood insurance. Flood 

losses are not covered by homeowner’s insurance. Disaster assistance will not take care of all the 

financial needs, if the historic structure is damaged by flood. Even if disaster assistance is 

available, it is often in the form of a low-interest loan which has to be repaid, and it is only 

available if the President formally declares a disaster. Flood insurance compensates for all covered 

losses and is the best form of financial protection against the devastating effects of floods. Flood 

insurance policies purchased by individual property owners help them recover from flooding more 

quickly. 

Increased Cost of Compliance (ICC) coverage is not available to a historic structure that is exempt 

from the floodplain management requirements if a historic structure is substantially damaged (44 

CFR §60.3). ICC coverage provides for the payment of a claim for the cost to comply with State or 

community floodplain management laws or ordinances after a direct physical loss by floods. When 

a building covered by a State or community declares the building to be substantially or repetitively 

damaged, ICC will help pay up to $30,000 for the cost to elevate, floodproof, demolish, or relocate 

the building. However, if an exemption is granted administratively through the community’s 

variance process, and conditions are placed in the variance requiring one of the mitigation measures 

that meet the local floodplain management criteria, ICC will be available if the structure is declared 

substantially damaged or repetitively damaged. 

Minimizing the Impacts of Flooding on 

Historic Structures 

Protection Measures for Historic Structures

The primary damage to historic buildings in a flood disaster is from immersion of building 

materials in floodwaters and the moving force of floodwaters that can cause structural collapse. 

Storm and sanitary sewer backup during flooding is also a major cause of flood damage to 

buildings. In addition, floods may cause a fire due to ruptured utility lines; result in the growth of 

mold and mildew; and lead to swelling, warping, and disintegration of materials due to prolonged 

presence of moisture. 
National Flood Insurance Program Floodplain Management Bulletin 

Page 10 of 22 

Although “historic structures” are exempt from the NFIP floodplain management requirements for 

new and substantially improved construction, flood mitigation measures should be a consideration 

to minimize flood damages when rehabilitating a historic structure or repairing a damaged historic 

structure (44 CFR §60.3). 

Rehabilitating or repairing a historic structure provides an opportunity to incorporate measures to 

reduce future flood damages. In addressing multiple historic structures in a historic district or a 

single historic structure, one of the first steps to undertake is to assess the flood risk and estimate 

the amount of potential flood losses. The “how-to” guides described in the Hazard Mitigation 

Planning Can Benefit Historic Structures section of this Bulletin can help in assessing the flood risk 

and the potential flood losses to historic structures. The “how-to” guides can also help in 

identifying, evaluating, and prioritizing possible mitigation measures that reduce flood damages. 

Mitigation measures can take a variety of forms from simple low-cost improvements such as 

elevating utilities and mechanical equipment to structural measures such as elevation, dry 

floodproofing, or relocating the building to a site outside the Special Flood Hazard Area. Even the 

more costly measures such as elevation, dry-floodproofing, or relocation can have significant 

benefits relative to their cost including: 

• Reduction of flood damages. The buildings may not sustain flood damages or at least those 

damages will be significantly less than if no mitigation measures were implemented. 

• Reduction in flood insurance premiums. Buildings that are elevated to or above the BFE or 

relocated out of the floodplain can qualify for flood insurance at actuarial rates that are generally less expensive than even the subsidized flood insurance rates charged to existing 

structures. 

• Long-term preservation of the building. Historic structures that are repeatedly flooded will 

deteriorate and eventually may have to be demolished unless they are protected from flooding. Mitigation measures can help preserve the building for future generations. 

One of the challenges in mitigating the flood risk to a “historic structure” is the need to incorporate 

mitigation measures in such a way that the structure does not lose its historic designation. When 

evaluating mitigation measures for historic structures, care should be taken so that new designs and 

new materials do not obscure existing significant historic features. Retrofitting a historic structure 

to reduce flood damages can be done that it has minimal impact on the structure’s historic integrity 

and so that it maintains its historic designation. 

A range of mitigation measures may be available for a particular historic structure. By adhering to 

the Secretary of the Interior’s Standards for the Treatment of Historic Properties and by seeking 

the help of an architect or engineering professional experienced in rehabilitating historic structures, 

a structure’s original historic setting, scale, and distinctive features can be preserved. You may 

want to also refer to the Preservation Briefs published by the National Park Service, which provide 

guidance on preserving, rehabilitating, and restoring historic buildings. You may also want to seek 

guidance from your State Historic Preservation Officer or Tribal Historic Preservation Officer. 
National Flood Insurance Program Floodplain Management Bulletin 

Page 11 of 22 

There is a variety of relatively simple measures that can be implemented to minimize the effects of 

flooding. Although these measures are designed to reduce flood damages, they may not eliminate 

flooding altogether. Many of the techniques described below may have minimal impact on the 

character-defining design features of the historic structure and some are relatively inexpensive to 

implement. Several of these will require a design professional and licensed contractor to 

implement. 

• Relocate contents to a safer location. For example, heirlooms and other cultural resources 

should be located above the BFE. At a minimum, valuable contents should be removed from 

flood-prone basements. 

• Create positive drainage around the building. In places where ground slope against the 

building facade is either flat or toward the building, increase the grade immediately adjacent 

to the façade to achieve positive drainage away from the building. In some situations, existing masonry and concrete window wells around basement windows may need to be built up 

to retain the extra height of the fill. 

• Protect mechanical and utility equipment. Elevating mechanical and utility equipment 

(including electrical, heating, ventilation, plumbing and air conditioning equipment) above 

the BFE can protect them from flood damage. Guidance for protecting mechanical and utility equipment from flooding can be found in the FEMA publication, Protecting Building 

Utilities from Flood Damage, Principles and Practices for the Design and Construction of 

Flood Resistant Building Utility Systems (FEMA 348/November 1999). 

• Remove modern finished materials from basements or other areas that are floodprone. 

Often historic structures are constructed from materials that are relatively flood-resistant. 

For example, basements often had stone or rubble walls and dirt floors. These buildings often were repeatedly flooded with minimal flood damages except to building contents. In 

more recent years many of these areas have been finished off using modern materials that 

are less resistant to flood damage and building utilities added. It may be possible to wetfloodproof the building merely by removing these modern materials and restoring these 

areas to their original configuration. 

• Use flood resistant materials below the BFE. When rehabilitating or repairing a damaged 

historic structure, use flood resistant materials below the BFE to improve the structure’s 

ability to withstand flooding. Guidance for using flood resistant materials can be found in 

Technical Bulletin 2-93, Flood-Resistant Materials Requirements for Buildings Located in 

Special Flood Hazard Area in accordance with the National Flood Insurance Programs. 

• Fill in the basement. For historic structures with basements, a simple solution to minimize 

flood damage and reduce the potential for structural damage is to abandon the basement, 

raise any mechanical and utility equipment, and fill in the basement with sand or gravel. 

• Wet floodproofing the basement. This measure allows the internal flooding of a basement. 

Flooding of a structure’s interior is intended to counteract hydrostatic pressure on the walls, 

surfaces, and supports of the structure by equalizing interior and exterior water levels during 

a flood. Inundation also reduces the danger of buoyancy from hydrostatic uplift forces. 

Such measures may require alteration of a basement’s design and construction, use of flood-
National Flood Insurance Program Floodplain Management Bulletin 

Page 12 of 22 

resistant materials, adjustment of the basement’s maintenance, relocation of equipment and 

contents, and emergency preparedness. Guidance for wet floodproofing a basement can be 

found in Technical Bulletin 7-93 Wet Floodproofing Requirements for Structures Located in 

Special Flood Hazard Areas in accordance with the National Flood Insurance Program. 

• Install “mini”-floodwalls to protect openings, such as a window well. For low level flooding, a type of “mini”-floodwall can be used to permanently protect various types of openings. Possible materials for this use include brick, concrete block and poured concrete. 

They should be supported by and securely tied into a footing so that they will not be undercut by scouring and the soil under these walls should be fairly impervious to control seepage. Some form of sealant may be needed on the outside to control seepage. 

• Temporary measures. Where it is not possible to use the above measures to protect a building from flooding, it may be possible to use temporary measures to reduce flood damages. 

Examples include sand-bagging openings, installing temporary barriers or flood shields in 

openings, and evacuating building contents to floors above the flood level. In order for this 

approach to work, one must develop an emergency plan and stock-pile the required materials ahead of time. The amount of flood warning time available for the site is critical and 

it must be ensured that adequate personnel are available to install the measures. Do not try 

to keep water out of buildings unless an engineering analysis is conducted to ensure that the 

walls are strong enough to withstand flood forces (hydrostatic, hydrodynamic, debris, and 

buoyancy). 

Property owners may want to undertake more extensive mitigation measures, if there is a likelihood 

of significant or more frequent flood damage to the historic structure. These mitigation measures 

could include elevating, floodproofing, or relocating the structure to a site that is outside of the 

Special Flood Hazard Area. These mitigation measures are described below. 

Elevation 

One of the common methods of protecting flood-prone buildings is to elevate the lowest floor of a 

structure above the BFE (elevation of the one-percent-annual chance flood). Elevation is an 

effective mitigation measure, if designed and constructed appropriately to withstand flood forces. 

Although elevation is a practical solution for flooding problems, the flooding conditions and other 

hazards at the site must be carefully examined so that the most suitable technique and foundation 

type can be determined. There are two types of elevation to consider: (1) The entire building is 

lifted and placed on a new elevated foundation (columns, piers, posts, or raised foundation walls 

such as a crawl space). (2) In situations where it is possible to leave the exterior of the building the 

same, raise the interior floor of the building above the BFE. This may be an alternative for older 

stone buildings with high ceilings and elevated window sills. 
National Flood Insurance Program Floodplain Management Bulletin 

Page 13 of 22 

Elevation of a historic residence in Mandeville, Louisiana 

Elevation of a historic residence in Mandeville, Louisiana 

Essentially, the steps 

required for elevating a 

building are largely the 

same in all cases. A cradle 

of steel beams is inserted 

under the structure; jacks 

are used to raise both the 

beams and structure to the 

desired height; a new 

elevated foundation for the 

house is constructed; and 

the structure is then 

lowered back onto the new 

foundation and 

reconnected. At a 

minimum, the foundation 

of the elevated structure must be able to withstand the expected loads at a site which may include 

hydrostatic pressure, hydrodynamic loads from velocity water and wave impacts, debris impact 

resulting from the flood, and buoyancy. The foundation must also be able to resist undermining by 

any expected erosion or scour. Therefore, the flooding characteristics and building type and 

condition will need to be examined to determine which type of foundation will be the most suitable. 

While elevating a structure above the BFE will provide the structure the most protection, a less 

intrusive elevation may be desired or more feasible for a historic structure. Other protection 

measures, such as elevating utilities and equipment above the BFE, should be considered if 

elevating a historic structure to the BFE is not practicable. 

Elevation of a historic structure 

does not have to be achieved by 

unsightly pilings or other 

foundation that would impair the 

aesthetics of a historic district. The 

structure could be elevated on 

pilings or foundation walls and the 

foundation area could then be 

covered by an architecturally 

pleasing facade that is consistent 

with materials from the historic 

structure. The lower area can also 

be camouflaged with landscaping. 
National Flood Insurance Program Floodplain Management Bulletin 

Page 14 of 22 

113 Calhoun today 

Photo courtesy of 113 Calhoun Street Foundation. 

Elevation in South Carolina. 113 

Calhoun Street is a 125-year old, three-story 

house that stands in the heart of the downtown 

historic district of Charleston, South Carolina. 

Already abandoned for several years by the time 

Hurricane Hugo struck in 1989, 113 Calhoun 

Street was in serious danger of collapse by 1997. 

Instead of demolishing the building, the City of 

Charleston donated it to the 113 Calhoun Street 

Foundation, a non-profit partnership formed 

between the South Carolina Sea Grant Consortium, Clemson University, and the City of 

Charleston. 

Using creative design solutions the 113 Calhoun 

Street Foundation transformed the derelict 

building into an educational center. Primary 

funding for the initial construction was provided 

by FEMA, while additional support, including 

the donation of products and services, came from 

the private sector. It was determined that an 

elevation above the BFE would not have been 

appropriate for 113 Calhoun Street. Such an 

elevation would have raised the building more 

than 5 feet, which would not have been in 

keeping with the surrounding streetscape and 

character of the historic district. Instead, the 

organization elevated the house only one foot, 

undertaking a variety of other types of interior 

and exterior improvements to protect against 

hazards. 

Even though it was elevated to below the BFE, 

the house is still protected from minor flooding 

events and suffers less damage in major flooding 

events. Improvements to the house included the 

following: 

• Placing HVAC ductwork at ceiling level 

and returns above the BFE. 

• Placing electrical, telephone, and 

computer outlets above the BFE, with no 

splices or connections below the BFE. 

113 Calhoun at inception of project 

Photo courtesy of 113 Calhoun Street Foundation. 
National Flood Insurance Program Floodplain Management Bulletin 

Page 15 of 22 

Frame building elevated on concrete block foundation faced with brick veneer. 

Belhaven, North Carolina.

• Installing interior decorative wainscoting to the BFE. This wainscoting consisted of waterresistant material, and could be removed to dry after a flood event. 

• Designing interior structural elements so that a continuous load path was created that minimized weak links in the building’s structural system. 

• Replacing the building’s deteriorated original foundation of unreinforced masonry brick 

with a new foundation consisting of concrete footings with steel ties. This new system allowed new timbers members to be bolted to the foundation, protecting against the twisting 

movements and other movements caused by seismic and wind forces. Brick from the original foundation was re-used as a veneer on the new foundation. 

Elevation in Belhaven, North Carolina. The Town of Belhaven, North Carolina, along 

the Pungo River, is subject to repeated flooding. In its last flood event, over 60 percent of the 

town’s buildings were damaged, including most of the buildings in the National Register-listed 

Belhaven Historic District. In an effort to retain the town’s historic and economic link to the 

waterfront, the decision was made to elevate the 379 buildings in place rather than relocate them to 

higher ground or demolish and rebuild them. 

With assistance from 

the North Carolina 

State Historic 

Preservation Officer, 

plans were developed 

for an elevation 

project that would best 

preserve the historic 

character of the 

district. In the plan, 

frame buildings were 

raised onto concrete 

block foundations 

faced with brick 

veneer. Brick 

buildings were 

elevated onto 

continuous concrete block foundations, which were also faced with brick veneer. A projecting 

brick course was used to demarcate where the original house ended and the new foundation began. 

Additional guidance was drafted for preserving porches, railings, balusters, and steps, and for 

replacing old materials with appropriate new materials where necessary. 

To prepare for the elevation project, large-format archival photographs were taken of each building 

that would be included in the project. These photographs provided a permanent record of the 

historic appearance of the district. Due to all these extra planning efforts for preserving its historic 

properties, the Belhaven Historic District was able to maintain its National Register status. 
National Flood Insurance Program Floodplain Management Bulletin 

Page 16 of 22 

By the time the next flood struck Belhaven, 32 of the planned 379 houses were elevated. It is 

estimated that elevation of these 32 properties alone saved the town over $1.3 million in direct and 

indirect damages. 

Floodproofing 

Another alternative is to “floodproof” the building, so that it will not sustain damage or so that 

damages are minimized. There are two types of floodproofing commonly called “dryfloodproofing” and “wet-floodproofing.” Dry floodproofing means making a building watertight, 

substantially impermeable to floodwaters. This form of floodproofing requires that the building be 

properly anchored to resist flotation, collapse, and lateral movement. It also may require the 

reinforcement of walls to withstand flood forces and impact forces generated by floating debris; the 

use of membranes and other sealants to reduce seepage of floodwater through walls and wall 

penetrations; the installation of pumps to control interior water levels; the installation of check 

valves to prevent entrance of floodwater or sewage flows through utilities; and the location of 

electrical, mechanical, utility, and other valuable vulnerable equipment and contents above the 

expected flood level. Dry-floodproofing must be implemented with an appropriate design by a 

registered professional engineer or architect. Additional guidance on dry floodproofing can be 

found in Technical Bulletin 3-93 Non-Residential Floodproofing – Requirements and Certification 

for Buildings Located in Special Flood Hazard Areas in accordance with the National Flood 

Insurance Program and in Floodproofing Non-Residential Structures (FEMA 102/May 1986). 

Wet-floodproofing allows for the flooding of a structure’s interior to equalize hydrostatic pressure 

on exterior walls, surfaces, and supports of the structure during a flood. Application of wetfloodproofing as a flood protection technique should be limited to specific situations in A Zones 

(including A, AE, A1-30, AH, AO, and AR zones). 

 

Flooding of a structure’s interior is intended to counteract hydrostatic flood forces on the exterior 

walls, surfaces, and supports of the structure during a flood. Inundation also reduces the danger of 

buoyancy from uplift forces. Use of wet floodproofing for historic structures requires careful 

consideration of protection techniques. 

Building materials for the area that is to be wet-floodproofed should be replaced with flood 

resistant materials. Valuable contents should be relocated to or above the BFE. Light, portable 

furnishings should be able to be moved quickly and easily before a flood. Utilities and equipment 

should be elevated to or above the BFE or located on a platform that is above the BFE. Consideration must be given to flood duration, frequency, and depth to determine if wet-floodproofing is a 

viable option. For example, flood-prone basements may be modified, so that they can be flooded 

without damage to the building or foundation. Additional guidance on wet floodproofing can be 

found in Technical Bulletin 7-93 Wet Floodproofing Requirements for Structures Located in 

Special Flood Hazard Areas in accordance with the National Flood Insurance Program. 
National Flood Insurance Program Floodplain Management Bulletin 

Page 17 of 22 

Floodproofing in Wisconsin. Flooding is an ongoing part of life in the rural riverside 

town of Darlington, Wisconsin, having caused millions of dollars in property damage over the past 

decade. Following the 

devastating damage from the 

1993 floods, the town could 

follow one of the three routes: 

do nothing and continue to 

suffer the periodic floods; 

move the central business 

distinct out of the floodplain 

and upset the local economy 

and sense of community; or 

do something innovative. 

Darlington chose innovation. It 

found creative solutions to retain 

the historic charm of its nineteenth 

century business district, while 

eliminating the threat of future 

flood devastation. 

The town took advantage of the 

very high ceilings common to many 

of the older buildings in Darlington; their height allowed first floors 

to be elevated out of flood danger 

with minimal impact to other 

historic features. Basements were 

filled with sand and gravel, 

floodproofing that portion of the 

building most vulnerable to flooding, and all utilities were upgraded and raised. All these measures 

were implemented without altering the exteriors or disrupting the historic integrity of these older 

buildings. 

These mitigation measures resulted in the 

successful floodproofing of the historic central 

business district against the 100-year flood 

event, as well as the revitalization of 

Darlington’s economy. 

The successful integration of historic 

preservation and hazard mitigation earned 

Darlington a Preservation Achievement Award 

from the State Historical Society of Wisconsin. 

Restored and retrofitted buildings in Downtown Darlington, Wisconsin 

To provide additional protection against floodwater, removable 

watertight floodgates were incorporated into the buildings 

Floodproofing the vestibule of a storefront 
National Flood Insurance Program Floodplain Management Bulletin 

Page 18 of 22 

Relocation 

Relocation is the mitigation measure that can offer the greatest security from future flooding. 

Relocation involves moving the entire structure out of the floodplain or it may involve dismantling 

a structure and rebuilding it elsewhere. It may be possible to relocate a building to a higher part of 

the same parcel or lot, but often it will be necessary to move the building to another site. In either 

case, it is the most reliable of all mitigation measures. In addition to relieving the property owner 

from future anxiety about flooding, this method can offer the opportunity to significantly reduce or 

even eliminate the need 

for flood insurance. 

Relocation may be the 

best option in cases 

where the building site is 

subject to repeat flooding 

or severe flooding, where 

flood depths and 

velocities can have 

significant impact on the 

building. 

Obviously, moving a 

structure is a complex 

operation and will have to 

be done by a professional 

with experience in 

relocating structures. 

Relocation generally 

involves raising the 

building and placing it on a wheeled vehicle, usually a large flatbed trailer. The building is then 

transported to the new site and lowered onto a new foundation. In general, structures over a crawl 

space or basement are the easiest to relocate, while structures that are slab-on-grade or multi-story 

are more difficult. Masonry buildings, buildings with stone or brick veneer, and buildings with 

chimneys may require extensive bracing to prevent cracking or structural failure. As structures 

become larger, moving them may become more complicated and more expensive. 

Relocation may, in some cases, be an appropriate option for historic structures by moving them out 

of harm’s way. However, historic structures often share important features to the site, such as 

landscaping, outbuildings, alleyways, orientation, setback from the street, or other historical 

context. These contributing features often help to define a neighborhood’s historic significance. If 

this option is being considered for a historic structure, consult with a historic preservation 

professional. The State Historic Preservation Officer or Tribal Historic Preservation Officer can 

also offer guidance. An example of a historic structure, which was relocated out of harm’s way, 

follows. 

Built by John Holm in 1847, the Magnolia Hotel, badly damaged from 

Hurricane Camille in 1969, was moved 100 yards north and restored by 

the City of Biloxi in 1972. As a result, the hotel experienced only minimal 

flooding during Hurricane Katrina. 
National Flood Insurance Program Floodplain Management Bulletin 

Page 19 of 22 

Relocation in Fulton, New York. On January 19, 1996, floodwaters of the Schoharie 

Creek rose nearly 18 feet damaging many properties in the Town of Fulton, in Schoharie County, 

New York. The Town of Fulton submitted a Hazard Mitigation Grant Program application to 

FEMA for the acquisition and demolition of 12 properties. In reviewing the Town of Fulton’s 

application, FEMA initiated consultation under section 106 of the National Historic Preservation 

Act. As a result, FEMA determined and the New York State Historic Preservation Officer 

concurred that one of the buildings 

in the application – known as the 

“Bruchmann residence” – was 

eligible for inclusion on the 

National Register of Historic 

Places and that its demolition 

would result in an “adverse 

effect.” The residence is 

significant as a notable and 

substantially intact example of a 

mid-19th century vernacular 

design and construction. 

Based on the “adverse effect” determination, a Memorandum of Agreement (MOA) was negotiated 

between the State Historic Preservation Officer, FEMA, and the Town of Fulton wherein the town 

would explore alternatives to demolition. The town implemented an advertising campaign in an 

attempt to identify a party willing and able to relocate the structure to another site. After more than 

2 years, an interested party submitted a statement of interest to the applicant and a deal was struck. 

The house was re-erected on its new site in Delaware County. 

Hazard Mitigation Planning Can Benefit Historic 

Structures 

Historic properties and cultural resources are valuable, economic assets in communities throughout 

the United States. For many communities, historic and cultural resources are a catalyst for 

economic development. Often not considered are the potentially devastating effects that flooding 

can have on historic properties. When disaster strikes and a community’s historic resources are 

damaged, the economic and social vitality of the community can be severely impacted. Communities can take steps to minimize the impacts of flooding on the community’s historic resources by 

integrating historic property and cultural resource protection into hazard mitigation planning. 

FEMA has developed a series of mitigation planning “how-to” guides for the purpose of assisting 

communities, States, and Tribes in developing an effective hazard mitigation plan. These guides 

have been developed by FEMA to provide an overview of the core elements associated with hazard 

mitigation planning. The four core elements include – organizing resources, assessing risks, 

developing a mitigation plan, and implementing the plan and monitoring progress. These “how-to 

series” include: 

Dismantling of Bruchmann residence, May 2000
National Flood Insurance Program Floodplain Management Bulletin 

Page 20 of 22 

• Getting started with the mitigation planning process, including important considerations for 

how one can organize efforts to develop an effective mitigation plan (FEMA 386-1); 

• Identifying hazards and assessing losses to community, State, or Tribe (FEMA 386-2); 

• Setting mitigation priorities and goals for community, State, or Tribe, and writing the plan 

(FEMA 386-3); and 

• Implementing the mitigation plan, including project funding and maintaining a dynamic 

plan that changes to meet new developments (FEMA 386-4). 

One particular guide developed specifically to address historic properties and cultural resources is 

the FEMA publication titled Integrating Historic Property and Cultural Resource Considerations 

Into Hazard Mitigation Planning (FEMA 386-6 / May 2005). This guide should be used in 

conjunction with the four guides described above. This guide will help communities accomplish 

the following with respect to historic structures and historic districts: 

• Identify and pull together resources for incorporating historic property and cultural resource 

considerations into a hazard mitigation plan; 

• Determine which historic properties and cultural resources are likely to be damaged in a 

disaster and prioritize them for protection; 

• Evaluate potential hazard mitigation actions for historic properties and cultural resources 

through the use of benefit-cost analysis and other decision-making tools; and 

• Develop and implement a hazard mitigation plan that addresses historic properties and 

cultural resources. 

To obtain copies of these publications, refer to Further Information section and Order Information 

section. 

Further Information

State and Local Mitigation Planning 

“How-To” Guides 

Getting Started – building support for mitigation planning, FEMA 386-1, September 2002. 

Understanding Your Flood Risk – identifying hazards and estimating losses, FEMA 386-2, August 

2001. 

Developing the Mitigation Plan – identifying mitigation actions and implementation strategies, 

FEMA 386-3, April 2003. 

Bringing the Plan to Life – implementing the hazard mitigation plan, FEMA 386-4, August 2003. 

Integrating Historic Property and Cultural Resource Considerations Into Hazard Mitigation 

Planning, FEMA 386-6, May 2005. 
National Flood Insurance Program Floodplain Management Bulletin 

Page 21 of 22 

Other Mitigation Documents 

Homeowner’s Guide to Retrofitting, Six Ways to Protect Your House from Flooding, FEMA 312, 

June 1998. 

Floodproofing Non-Residential Structures, FEMA 102, May 1986.

Flood-Resistant Materials Requirements for Buildings Located in Special Flood Hazard Areas in 

Accordance with the National Flood Insurance Program, FEMA Technical Bulletin 2-93, 

FIA-TB-2. 4/93.

Hurricane Katrina in the Gulf Coast, Mitigation Assessment Team Report, Building Performance 

Observations, Recommendations, and Technical Guidance, FEMA 549, July 2006. Chapter 6 and 

Appendix J. 

Openings in Foundation Walls for Buildings Located in Special Flood Hazard Areas in accordance 

with the National Flood Insurance Program, FEMA Technical Bulletin 1-93, FIA-TB-1 4/93. 

Non-Residential Floodproofing-Requirements and Certification for Buildings Located in Special 

Flood Hazard Areas in accordance with the National Flood Insurance Program, FEMA Technical 

Bulletin 3-93, FIA-TB-3. 4/93. 

Protecting Building Utilities From Flood Damage, Principles and Practices for the Design and 

Construction of Flood Resistant Building Utility Systems, FEMA 348, November 1999. 

Recommended Residential Construction for the Gulf Coast, Building on Strong and Safe Foundations, FEMA 550, July 2006. 

Repairing Your Flood Home, Federal Emergency Management Agency and the American Red 

Cross, ARC 4477 or FEMA 234, 1992. 

Wet Floodproofing Requirements for Structures Located in Special Flood Hazard Areas in 

accordance with the National Flood Insurance Program, Technical Bulletin 7-93, FIA-TB-7 12/93. 

To obtain a copy of these publications, see the section on Ordering Information. They are also 

available to view and download from http://www.fema.gov/library/index.jsp. 
National Flood Insurance Program Floodplain Management Bulletin 

Page 22 of 22 

Comments 

Any comments on the Floodplain Management Bulletin should be directed to: 

 DHS/FEMA

 Mitigation Directorate 

 500 C St., SW 

 Crystal City 

 Washington, D.C. 20472 

Ordering Information 

This document can be downloaded from the following website: 

http://www.fema.gov/library/index.jsp. 

Copies of this bulletin and the above listed publications are available from: 

 FEMA Distribution Facility 

 P.O. Box 2012 

 Jessup, MD 20794-2012. 

FEMA’s Distribution Facility also accepts telephone requests (1-800-480-2520) and facsimile 

requests (301-362-5335). 

This Bulletin represents FEMA’s interpretation of a statutory or regulatory requirement. The 

Bulletin itself does not impose legally enforceable rights and obligations, but sets forth a standard 

operating procedure or agency practice that FEMA employees follow to be consistent, fair, and 

equitable in the implementation of the agency’s authorities.