Sprayed polyurethane foam and closed- cell plastic foams are the only materials that FEMA classifies as acceptable flood
damage-resistant insulation materials for
floors, walls and ceilings in its building design
criteria for special flood hazard areas (SFHAs).
This requirement applies to new construction,
repair of substantially damaged buildings, and
substantial improvement of existing buildings
in SFHAs. To protect buildings constructed
in SFHAs, FEMA’s National Flood Insurance
Program (NFIP) requires the use of building
materials that are ”resistant to flood damage.”
Home Builder’s Guide to Coastal
Construction Technical Fact Sheet
Series (FEMA P-499)
FEMA has produced a series of 37 fact sheets to
provide technical guidance and recommendations
concerning the construction of coastal residential
buildings. The fact sheets present information
aimed at improving the performance of buildings
subject to flood and wind forces in coastal
FEMA Technical Bulletin 2 – ”Flood Damage-
Resistant Materials Requirements” for Buildings
Located in Special Flood Hazard Areas in
accordance with the National Flood Insurance
Program shows closed cell spray foam as the
only Class 5 insulation.
Sprayed closed-cell foam polyurethane insulation is used to
fill wall cavities in framed construction (see Figure 5). When
sprayed, it expands and hardens forming a rigid air barrier
and acting as a moisture retardant.
FEMA designates sprayed polyurethane foam
and closed-cell plastic foams as a Class 5 flood
damage-resistant building material. Class 5,
which is FEMA’s highest rating, are materials
considered highly resistant to floodwater
damage, including damage caused by moving
water, and can survive wetting and drying and
may be successfully cleaned after a flood to
render them free of most harmful pollutants.
•;Sprayed closed-cell foam insulation expands to fill wall
cavities, small holes, and gaps as it expands, producing a
rigid barrier that results in reduced energy costs.
•;It is quick to apply and may require less time to install
than conventional batt insulation.
•;It offers acceptable flood resistance, which is shown in
NFIP Technical Bulletin 2-08, Flood-Resistant Material
Requirements for Buildings Located in Special Flood
Hazard Areas in accordance with the National Flood
The documents illustrate National Flood
Insurance Program (NFIP) regulatory
requirements, the proper siting of coastal
buildings, and recommended design and
construction practices for building components,
including structural connections, the building
envelope, and utilities.
Things to consider if building with sprayed closed-cell foam
Section 1. 7, titled ”Coastal Building Materials”
includes references to closed-cell spray
polyurethane foam insulation.
Section 1. 8 – titled ”Non Traditional Building
Materials” contains an entire section about the
usage and benefits of closed-cell spray foam
insulation as a flood resistant material.
NOTE: FEMA specifically discusses Closed-cell foam
as being classified as ”acceptable,” however to the
trained eye, you will notice the photo they use shows
•;Tests have shown that sprayed foam insulation can
improve the strength of structural framing systems
and connections. However, structural framing systems
and connections must be designed and constructed in
accordance with all applicable building codes.
•;While closed-cell foam is a flood-resistant material, it
should be used in conjunction with preservative-treated,
or naturally durable, wood or corrosion-resistant metal
•;Closed-cell foam should not be confused with other
types of insulation. Some varieties of insulation on
the market may be more cost effective and more
environmentally friendly; however, many of these
products are not considered flood-resistant materials.
Testing reports and provisions of the building code
should be consulted for applicability in a coastal
•;Sprayed foam systems (such as those used in a wall
system) create an assembly that when inundated by
floodwaters may not be easily dried. For this reason,
they are not appropriate to use below the BFE and are
not considered flood-resistant material unless the entire
assembly has been determined to be flood-resistant.
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