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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.