Summary of Coastal Construction Requirements and Recommendations
Home Builder’s Guide to Coastal Construction
FEMA 499/August 2005
Technical Fact Sheet No. 2

Purpose: To summarize National Flood Insurance Program (NFIP) regulatory 
requirements concerning coastal construction and provide recommendations for 
exceeding those requirements in some instances.

Key Issues
--New construction* in coastal flood hazard areas (V zones and A zones) must 
meet minimum NFIP and community requirements. Repairs, remodeling, and additions 
must meet community requirements and may also be subject to NFIP requirements.
--NFIP design and construction requirements are more stringent in V zones than 
in A zones, in keeping with the increased flood, wave, floodborne debris and 
erosion hazards in V zones.	
--Some coastal areas mapped as A zones may be subject to damaging waves and 
erosion (these areas are often referred to as Coastal A Zones). Buildings in 
these areas constructed to minimum NFIP A-zone requirements may sustain major 
damage or be destroyed during the Base Flood. It is strongly recommended that 
buildings in A zones subject to breaking waves and erosion be designed and 
constructed to V-zone standards.
--Buildings constructed to minimum NFIP A-zone standards and subject solely to 
shallow flooding without the threat from breaking waves and erosion will 
generally sustain only minor damage during the Base Flood.
--Following the recommendations in the table below will result in lower damage 
to the building and reduced flood insurance premiums (see the V-Zone Risk Factor 
Rating Form in FEMA's Flood Insurance Manual 
(http://www.fema.gov/nfip/manual.shtm).

* For floodplain management purposes, new construction means structures for 
which the start of construction began on or after the effective date of a 
floodplain management regulation adopted by a community. Substantial 
improvements, repairs of substantial damage, and some enclosures must meet most 
of the same requirements as new construction.

The following tables summarize NFIP regulatory requirements and recommendations 
for exceeding those requirements for both (1) new construction and (2) repairs, 
remodeling, and additions.

Requirements and Recommendations for New Construction (Note a)

General Requirements

Design (Also see Certification)
--V Zone: Requirement: building and its foundation must be designed, 
constructed, and anchored to prevent flotation, collapse, and lateral movement 
due to simultaneous wind and water loads (see Fact Sheet No. 5)
--Coastal A Zone (note b): Requirement: building must be designed, constructed, 
and anchored to prevent flotation, collapse, and lateral movement resulting from 
hydrodynamic and hydrostatic loads, including the effects of buoyancy. 
Recommendation: follow v-zone requirement.
--A Zone (note c): Requirement: building must be designed, constructed, and 
anchored to prevent flotation, collapse, and lateral movement resulting from 
hydrodynamic and hydrostatic loads, including the effects of buoyancy. 

Free of Obstructions
--V Zone: Requirement: the space below the lowest floor must be free of 
obstructions (e.g., free of any building element, equipment, or other fixed 
objects that can transfer flood loads to the foundation, or that can cause 
floodwaters or waves to be deflected into the building), or must be constructed 
with non-supporting breakaway walls, open lattice, or insect screening. (see 
Fact Sheet Nos. 5, 27)
--Coastal A Zone: Requirement: none. Recommendation: follow v-zone requirement.
--A Zone: Requirement: none

Materials (see Fact Sheet Nos. 1, 8)
--V Zone: Requirement: structural and nonstructural building materials at or 
below BFE must be flood-resistant.
--Coastal A Zone: Requirement: structural and nonstructural building materials 
at or below BFE must be flood-resistant.
--A Zone: Requirement: structural and nonstructural building materials at or 
below BFE must be flood-resistant.

Construction (See Fact Sheet No. 1) (Also see Certification)
--V Zone: Requirement: building must be constructed with methods and practices 
that minimize flood damage
--Coastal A Zone: Requirement: building must be constructed with methods and 
practices that minimize flood damage
--A Zone: Requirement: building must be constructed with methods and practices 
that minimize flood damage 

Siting (see Fact Sheet Nos. 6, 7)
--V Zone: Requirement: all new construction shall be landward of mean high tide; 
alteration of sand dunes and mangrove stands that increases potential flood 
damage is prohibited. Recommendation: site new construction landward of long-
term erosion setback and landward of area subject to erosion during 100-year 
coastal flood event.
--Coastal A Zone: Requirement: encroachments into floodways designated along 
rivers and streams are prohibited unless they will cause no increase in flood 
stage; where floodways have not been designated, encroachments into the SFHA 
cannot increase the BFE by more than 1 foot. Recommendation: follow v-zone 
requirement.
--A Zone: Requirement: encroachments into floodways designated along rivers and 
streams are prohibited unless they will cause no increase in flood stage; where 
floodways have not been designated, encroachments into the SFHA cannot increase 
the BFE by more than 1 foot.

Foundation

Structural Fill
--V Zone: prohibited (see Fact Sheet No. 11)
--Coastal A Zone: Allowed, but not recommended; compaction required where used; 
protect against scour and erosion (note d) (See Fact Sheet No. 11)
--A Zone: Allowed; compaction required where used; protect against scour and 
erosion (note d)

Solid Foundation (See Fact Sheet Nos. 11, 15)
--V Zone: prohibited
--Coastal A Zone: allowed, but not recommended (note d)
--A Zone: allowed (note d)

Open Foundation (see Fact Sheet No. 11)
--V Zone: required.
--Coastal A Zone: recommended (note d)
--A Zone: allowed (note d)

Lowest Floor Elevation (see Fact Sheet No. 4) (Also see Certification)
--V Zone: See Bottom of Lowest Horizontal Structural Member (see Fact Sheet No. 
5)
--Coastal A Zone: Requirement: top of floor must be at or above BFE (note e). 
Recommendation: elevate bottom of lowest horizontal structural member to or 
above BFE (note e)
--A Zone: Requirement: top of floor must be at or above BFE (note e). 
Recommendation: elevate bottom of lowest horizontal structural member to or 
above BFE (note e).

Bottom of Lowest Horizontal Structural Member (see Fact Sheet No. 4)
--V Zone: must be at or above BFE (note e) (see Fact Sheet No. 5) 
--Coastal A Zone: allowed below BFE (note e), but not recommended (note d). 
Recommendation: follow v-zone requirement.
--A Zone: allowed below BFE (note e), but not recommended (note d). 
Recommendation: follow v-zone requirement.

Orientation of Lowest Horizontal Structural Member
--V Zone: Requirement: none. Recommendation: orient perpendicular to wave crest.
--Coastal A Zone: Requirement: none. Recommendation: follow v-zone requirement.
--A Zone: Requirement: none.

Freeboard (see Fact Sheet Nos. 1, 4)
--V Zone: Not required (note e), but recommended
--Coastal A Zone: Not required (note e), but recommended
--A Zone: Not required (note e), but recommended

Enclosures Below BFE (also see Certification) (see Fact Sheet No. 27)
--V Zone: Prohibited, except for breakaway walls, open lattice, and screening 
(note f). Recommendation: if constructed, use open lattice or screening instead 
of breakaway walls.
--Coastal A Zone: Allowed but not recommended. Requirement: if area is fully 
enclosed, enclosure walls must be equipped with openings to equalize hydrostatic 
pressure; size, location, and covering of openings governed by regulatory 
requirements. Recommendation: elevate on open foundation; if enclosure is 
constructed, use breakaway walls (with flood openings), open lattice, or 
screening, as required in V zone (notes f, g).
--A Zone: Allowed. Requirement: if area is fully enclosed, enclosure walls must 
be equipped with openings to equalize hydrostatic pressure; size, location, and 
covering of openings governed by regulatory requirements (notes f, g).

Nonstructural Fill
--V Zone: Allowed for minor landscaping and site drainage as long as fill dies 
not interfere with free passage of floodwaters and debris beneath building, or 
cause changes in flow direction during coastal storms that could result in 
damage to buildings. 
--Coastal A Zone: allowed (note h). Recommendation: follow v-zone requirement.
--A Zone: Allowed. Recommendation: follow v-zone requirement.

Use of Space Below BFE (note i) (see Fact Sheet No. 27)
--V Zone: Allowed only for parking, building access, and storage.
--Coastal A Zone: Allowed only for parking, building access, and storage.
--A Zone: Allowed only for parking, building access, and storage.

Utilities (note i)
--V Zone: Requirement: utilities, including ductwork and equipment, must be 
designed, located, and elevated to prevent floodwaters from entering and 
accumulating in components during flooding; utility lines must not be installed 
or stubbed out in enclosures below BFE.
--Coastal A Zone: Requirement: utilities, including ductwork and equipment, must 
be designed, located, and elevated to prevent floodwaters from entering and 
accumulating in components during flooding; utility lines must not be installed 
or stubbed out in enclosures below BFE.
--A Zone: Requirement: utilities, including ductwork and equipment, must be 
designed, located, and elevated to prevent floodwaters from entering and 
accumulating in components during flooding; utility lines must not be installed 
or stubbed out in enclosures below BFE.

Certification

Elevation
--V Zone: Requirement: bottom of lowest horizontal structural member must be at 
or above BFE (note e); electrical, heating, ventilation, plumbing, and air 
conditioning equipment and other service facilities (including ductwork) must be 
designed and/or located so as to prevent water from entering or accumulating 
within the components during flooding (see Fact Sheet Nos. 4, 5, 29)
--Coastal A Zone: Requirement: top of lowest floor must be at or above BFE (note 
e); electrical, heating, ventilation, plumbing, and air conditioning equipment 
and other service facilities (including ductwork) must be designed and/or 
located so as to prevent water from entering or accumulating within the 
components during flooding (see Fact Sheet Nos. 4, 29). Recommendation: follow 
v-zone requirement
--A Zone: Requirement: Requirement: top of lowest floor must be at or above BFE 
(note e); electrical, heating, ventilation, plumbing, and air conditioning 
equipment and other service facilities (including ductwork) must be designed 
and/or located so as to prevent water from entering or accumulating within the 
components during flooding (see Fact Sheet Nos. 4, 29). Recommendation: follow 
v-zone requirement

Structure
--V Zone: Requirement: registered engineer or architect must certify that design 
and methods of construction are in accordance with accepted standards of 
practice for meeting design requirements described under General Requirements 
(see Fact Sheet No. 5)
--Coastal A Zone: Requirement: none. Recommendation: follow v-zone requirement. 
--A Zone: Requirement: none. Recommendation: follow v-zone requirement.

Breakaway Walls (see Fact Sheet Nos. 5, 27) (Also see Enclosures Below BFE)
--V Zone: Requirement: walls must be designed to break free under larger of (1) 
design wind load, (2) design seismic load, or (3) 10 psf, acting perpendicular 
to the plane of the wall; if loading at which breakaway wall is intended to 
collapse exceeds 20 psf, breakaway wall design shall be certified; when 
certification is required, registered engineer or architect must certify that 
walls will collapse under a water load associated with the Base Flood and that 
elevated portion of building and its foundation will not subject to collapse, 
displacement, or lateral movement under simultaneous wind and water loads (note 
f). 
--Coastal A Zone: Requirement: not required, but recommended (note f, g) with 
open foundation in lieu of solid walls; if breakaway walls are used and enclose 
an area, flood openings are required. (see Fact Sheet Nos. 11, 15)
--A Zone: Requirement: none (note f, g)

Openings in Below BFE-Walls (see Fact Sheet Nos. 11, 15) (also see Enclosures 
Below BFE)
--V Zone: not applicable (note i)
--Coastal A Zone: Requirement: unless number and size of openings meet 
regulatory requirements, registered engineer or architect must certify that 
openings are designed to automatically equalize hydrostatic forces on walls by 
allowing automatic entry and exit of floodwaters.
--A Zone: Requirement: unless number and size of openings meet regulatory 
requirements, registered engineer or architect must certify that openings are 
designed to automatically equalize hydrostatic forces on walls by allowing 
automatic entry and exit of floodwaters.

Repairs, Remodeling, and Additions (see Fact Sheet No. 30 and consult AHJ (note 
k) for building code requirements)

Substantial Improvements and Repairs of Substantial Damage
--V Zone: Requirement: must meet current NFIP requirements concerning new 
construction in V zones (note k, l) except for siting landward of mean high tide 
[see Fact Sheet Nos. 4, 5, 7, 11, 15, 27, 29]
--Coastal A Zone: Requirement: must meet current NFIP requirements concerning 
new construction in A zones (note k, m) [see Fact Sheet Nos. 4, 11, 15, 27, 29]. 
Recommendation: follow v-zone requirement
--A Zone: Requirement: must meet current NFIP requirements concerning new 
construction in A zones (note k, m) [see Fact Sheet Nos. 4, 11, 15, 27, 29]. 
Recommendation: elevate bottom of lowest horizontal structural member to or 
above BFE.

Lateral Additions That Constitute Substantial Improvement
--V Zone: Requirement: both addition and existing building must meet current 
NFIP requirements concerning new construction in V zones (note k, l, n) [see 
Fact Sheet Nos. 4, 5, 7, 11, 15, 27, 29].
--Coastal A Zone: Requirement: only addition must meet current NFIP requirements 
concerning new construction in A zones (note k, m, o) (See Fact Sheet Nos. 4, 7, 
11, 15, 27, 29), provided existing building is not subject to any work other 
than cutting entrance in common wall and connecting existing building to 
addition; if any other work is done to existing building, it too must meet 
current NFIP requirements for new construction in A zones. Recommendation: 
follow v-zone requirement
--A Zone: Requirement: only addition must meet current NFIP requirements 
concerning new construction in A zones (note k, m, o) (See Fact Sheet Nos. 4, 7, 
11, 15, 27, 29), provided the existing building is not subject to any work other 
than cutting an entrance in a common wall and connecting the existing building 
to the addition; if any other work is done to existing building, it too must 
meet current NFIP requirements for new construction in A zones. Recommendation: 
elevate bottom of lowest horizontal structural member of addition to or above 
BFE (same for existing building if it is elevated).

Lateral Additions That Do Not Constitute Substantial Improvement
--V Zone: Requirement: post-Flood Insurance Rate Map (FIRM) existing building -- 
addition must meet NFIP requirements in effect at time building was originally 
constructed (note k, l, n). Pre-FIRM existing building -- NFIP requirements 
concerning new construction not triggered (note k) [see Fact Sheet Nos. 4, 5, 7, 
11, 15, 27, 29]. Recommendation: make addition compliant with current NFIP 
requirements for V-zone construction.
--Coastal A Zone: Requirement: post-FIRM existing building -- addition must meet 
NFIP requirements in effect at time building was originally constructed (note k, 
m, o) [see Fact Sheet Nos. 4, 7, 11, 15, 27, 29]. Pre-FIRM existing building – 
NFIP requirements concerning new construction not triggered (note k). 
Recommendation: follow V-zone requirement.
--A Zone: Requirement: post-FIRM existing building -- addition must meet NFIP 
requirements in effect at time building was originally constructed (note k, m, 
o) [see Fact Sheet Nos. 4, 7, 11, 15, 27, 29]. Pre-FIRM existing building – NFIP 
requirements concerning new construction not triggered (note k). Recommendation:
elevate bottom of lowest horizontal structural member of addition to or above 
BFE (same for existing building if it is elevated) [see Fact Sheet No. 4].

Vertical Additions That Constitute Substantial Improvement 
--V Zone: Requirement: entire building must meet current NFIP requirements 
concerning new construction in V zones (note k, l, n) [see Fact Sheet Nos. 4, 5, 
7, 11, 15, 27, 29]. 
--Coastal A Zone: Requirement: entire building must meet current NFIP 
requirements concerning new construction in A zones (note k, m, o)[see Fact 
Sheet Nos. 4, 7, 11, 15, 27, 29]. Recommendation: follow V-zone requirement.
--A Zone: Requirement: entire building must meet current NFIP requirements 
concerning new construction in A zones (note k, m, o)[see Fact Sheet Nos. 4, 7, 
11, 15, 27, 29]. Recommendation: elevate bottom of lowest horizontal structural 
member to or above BFE [see Fact Sheet No. 4].

Vertical Additions That Do Not Constitute Substantial Improvement 
--V Zone: Requirement: post-FIRM existing building -- addition must meet NFIP 
requirements in effect at time building was originally constructed (note k, l, 
n) Pre-FIRM existing building -- NFIP requirements concerning new construction 
not triggered (note k) [see Fact Sheet Nos. 4, 5, 7, 11, 15, 27, 29]. 
Recommendation: make addition compliant with current NFIP requirements for V-
zone construction. 
--Coastal A Zone: Requirement: post-FIRM existing building -- addition must meet 
NFIP requirements in effect at time building was originally constructed (note k, 
m, o) Pre-FIRM existing building -- NFIP requirements concerning new 
construction not triggered (note k) [see Fact Sheet Nos. 4, 5, 7, 11, 15, 27, 
29]. Recommendation: follow V-zone requirement.
--A Zone: Requirement: post-FIRM existing building -- addition must meet NFIP 
requirements in effect at time building was originally constructed (note k, m, 
o) Pre-FIRM existing building -- NFIP requirements concerning new construction 
not triggered (note k) [see Fact Sheet Nos. 4, 5, 7, 11, 15, 27, 29]. 
Recommendation: elevate bottom of lowest horizontal structural member to or 
above BFE [see Fact Sheet No. 4].

Elevating on New Foundation
--V Zone: Requirement: new foundation must meet current NFIP requirements 
concerning new construction in V zones (note k, l); building must be properly 
connected and anchored to new foundation
--Coastal A Zone: Requirement: new foundation must meet current NFIP 
requirements concerning new construction in A zones (note k, m); building must 
be properly connected and anchored to new foundation. Recommendation: follow V-
zone requirement.
--A Zone: Requirement: new foundation must meet  current NFIP requirements 
concerning new construction in A zones (note k, m); building must be properly 
connected and anchored to new foundation. Recommendation: elevate bottom of 
lowest horizontal structural member to or above BFE  [see Fact Sheet No. 4].


Enclosures Below Buildings—-when enclosure constitutes a substantial improvement
--V Zone: Requirement: both enclosure and existing building must meet current 
NFIP requirements for new construction in V zones (note k, l, n) [see Fact Sheet 
Nos. 4, 5, 7, 11, 27, 29].
--Coastal A Zone: Requirement: both enclosure and existing building must meet 
current NFIP requirements for new construction in A zones (note k, m, o) [see 
Fact Sheet Nos. 4, 7, 11, 15, 27, 29]. Recommendation: follow V-zone 
requirement.
--A Zone: Requirement: both enclosure and existing building must meet current 
NFIP requirements for new construction in A zones (note k, m, o) [see Fact Sheet 
Nos. 4, 7, 11, 15, 27, 29]. Recommendation: elevate bottom of lowest horizontal 
structural member to or above BFE [see Fact Sheet No. 4].

Enclosures Below Buildings—-when enclosure does not constitutes a substantial 
improvement
--V Zone: Requirement: post-FIRM existing building -- enclosure must meet NFIP 
requirements in effect at time building was originally constructed (note k, l, 
n) Pre-FIRM existing building -- NFIP requirements concerning new construction 
not triggered (note k) [see Fact Sheet No. 27]. Recommendation: make enclosure 
compliant with current NFIP requirements for new V-zone construction.
--Coastal A Zone: Requirement: post-FIRM existing building -- enclosure must 
meet NFIP requirements in effect at time building was originally constructed 
(note k, m, o) Pre-FIRM existing building -- NFIP requirements concerning new 
construction not triggered (note k) [see Fact Sheet Nos. 15, 27]. 
Recommendation: construct only breakaway enclosures; install flood openings in 
enclosure; do not convert enclosed space to habitable use.
--A Zone: Requirement: post-FIRM existing building -- enclosure must meet NFIP 
requirements in effect at time building was originally constructed (note k, m, 
o) Pre-FIRM existing building -- NFIP requirements concerning new construction 
not triggered (note k)[see Fact Sheet Nos. 15, 27]. Recommendation: install 
flood openings in enclosure; do not convert enclosed space to habitable use.

Reconstruction of Destroyed or Razed Building
--V Zone: Requirement: where entire building is destroyed, damaged, or 
purposefully demolished or razed, replacement building must meet current NFIP 
requirements concerning new construction in V zones (note k, l), even if built 
on foundation from original building [see Fact Sheet Nos. 4, 5, 30].
--Coastal A Zone: Requirement: where entire building is destroyed, damaged, or 
purposefully demolished or razed, replacement building must meet current NFIP 
requirements concerning new construction in A zones (note k, m), even if built 
on foundation from original building [see Fact Sheet Nos. 4, 30]. 
Recommendation: follow V-zone requirement.
--A Zone: Requirement: where entire building is destroyed, damaged, or 
purposefully demolished or razed, replacement building must meet current NFIP 
requirements concerning new construction in A zones (note k, m), even if built 
on foundation from original building [see Fact Sheet Nos. 4, 30].

Moving Existing Building
--V Zone: Requirement: where existing building is moved to new location or site, 
relocated building must meet current NFIP requirements concerning new 
construction in V zones (note k, l) [see Fact Sheet Nos. 4, 5, 30].
--Coastal A Zone: Requirement: where existing building is moved to new location 
or site, relocated building must meet current NFIP requirements concerning new 
construction in A zones (note k, m) [see Fact Sheet Nos. 4, 30]. Recommendation:
follow V-zone requirement.
--A Zone: Requirement: where existing building is moved to new location or site, 
relocated building must meet current NFIP requirements concerning new 
construction in A zones (note k, m) [see Fact Sheet Nos. 4, 30]. 
Recommendation: elevate bottom of lowest horizontal structural member to or 
above BFE [see Fact Sheet No. 4]. 


Notes
a	“Prohibited” and “Allowed” refer to the minimum NFIP regulatory 
requirements; individual states and communities may enforce more stringent 
requirements that supersede those summarized here. Exceeding minimum NFIP 
requirements will provide increased flood protection and may result in lower 
flood insurance premiums.
b	In these areas, buildings are subject to flooding conditions similar to, 
but less severe than, those in V zones. These areas can be subject to breaking 
waves greater than or equal to 1.5 feet high (which can destroy conventional 
wood-frame and unreinforced masonry wall construction) and erosion (which can 
undermine shallow foundations).
c	In these areas, buildings are subject to flooding conditions similar to 
those in riverine A zones.
d	Some coastal communities require open foundations in A zones.
e	State or community may require freeboard or regulate to a higher elevation 
(e.g., Design Flood Elevation (DFE)).
f	Some coastal communities prohibit breakaway walls and allow only open 
lattice or screening.
g	If an area below the BFE in an A-zone building is fully enclosed by 
breakaway walls, the walls must meet the requirement for openings that allow 
equalization of hydrostatic pressure.
h	Placement of nonstructural fill adjacent to buildings in coastal AO zones 
is not recommended.
i	There are some differences between what is permitted under floodplain 
management regulations and what is covered by NFIP flood insurance. Building 
designers should be guided by floodplain management requirements, not by flood 
insurance policy provisions. For more information, see Section 9.3.1.1 in 
Chapter 9 of FEMA’s Coastal Construction Manual (FEMA 55).
j	Walls below BFE must be designed and constructed as breakaway walls that 
meet the minimum requirements of the NFIP regulations. For more information, see 
Section 6.4.3.3 in Chapter 6 of FEMA’s Coastal Construction Manual (FEMA 55).
k	Consult with authority having jurisdiction (AHJ) regarding more 
restrictive requirements for repairs, remodeling, and additions.
l 	NFIP requirements for new construction in V zones include those pertaining 
to Design and Construction, Flood-Resistant Materials, Siting, Foundations, 
Lowest Floor Elevation, Enclosures Below the BFE, Free of Obstructions, 
Utilities, and Certifications.
m 	NFIP requirements for new construction in A zones include those pertaining 
to Design and Construction, Flood-Resistant Materials, Siting, Foundations, 
Foundation Openings, Lowest Floor Elevation, Enclosures Below the BFE, 
Utilities, and Certifications.
n 	An addition in the form of an attached garage would not have to be 
elevated to or above the BFE, because its use (parking) would be allowed below 
the BFE; however, it would have to meet other NFIP requirements for new 
construction in V zones.
o 	An addition in the form of an attached garage would not have to be 
elevated to or above the BFE, because its use (parking) would be allowed below 
the BFE; however, it would have to meet other NFIP requirements for new 
construction in A zones.

[End of Fact Sheet No. 2]