In addition to the general requirements of Article IV of this chapter, the requirements of this section shall:
A.
Apply in flood hazard areas that are identified as coastal high hazard
areas (V Zones) and Coastal A Zones (if delineated).
B.
Apply to all development, new construction, substantial improvements
(including repair of substantial damage), and placement, replacement,
and substantial improvement (including repair of substantial damage)
of manufactured homes.
C.
Exception: In Coastal A Zones, the requirements of Article V of this chapter shall apply to substantial improvements (including repair of substantial damage) and substantial improvement of manufactured homes (including repair of substantial damage) and replacement manufactured homes. [Note: See "Coastal Construction Manual" (FEMA P-55).]
A.
The placement of structural fill for the purpose of elevating buildings
is prohibited.
B.
Buildings shall be located landward of the reach of mean high tide.
C.
Minor grading, and the placement of minor quantities of fill, shall
be permitted for landscaping and for drainage purposes under and around
buildings and for support of parking slabs, pool decks, patios, and
walkways.
D.
Site preparations shall not alter sand dunes unless an engineering
analysis demonstrates that the potential for flood damage is not increased.
New structures and substantial improvement (including repair of substantial damage) of existing structures shall comply with the applicable requirements of Article IV of this chapter and the requirements of this section.
A.
Foundations.
(1)
Structures shall be supported on pilings or columns and shall be
adequately anchored to such pilings or columns. Pilings shall have
adequate soil penetrations to resist the combined wave and wind loads
(lateral and uplift). Water loading values used shall be those associated
with the base flood. Wind loading values shall be those required by
applicable building codes. Pile embedment shall include consideration
of decreased resistance capacity caused by scour of soil strata surrounding
the piling.
(2)
Slabs, pools, pool decks, and walkways shall be located and constructed
to be structurally independent of structures and their foundations
to prevent transfer of flood loads to the structures during conditions
of flooding, scour, or erosion from wave-velocity flow conditions,
and shall be designed to minimize debris impacts to adjacent properties
and public infrastructure.
B.
C.
Certification of design. As required in § 117-15A(13) of this chapter, the applicant shall include in the application a certification prepared by a licensed professional engineer or a licensed architect that the design and methods of construction to be used meet the requirements of Subsection A, Subsection B, Subsection D, and the building code.
D.
Enclosures below the lowest floor.
(1)
Enclosures below the lowest floor shall be used solely for parking
of vehicles, building access, or limited storage.
(2)
Enclosures below the lowest floor shall be less than 299 square feet
in area (exterior measurement).
(3)
Walls and partitions are permitted below the elevated floor, provided
that such walls and partitions are designed to break away under flood
loads and are not part of the structural support of the building or
structure. [Note: See NFIP Technical Bulletin #9, "Design and Construction
Guidance for Breakaway Walls."]
(4)
Electrical, mechanical, and plumbing system components shall not
be mounted on or penetrate through walls that are designed to break
away under flood loads.
(5)
Walls intended to break away under flood loads shall be constructed
with insect screening or open lattice, or shall be designed to break
away or collapse without causing collapse, displacement, or other
structural damage to the elevated portion of the building or supporting
foundation system. Such walls, framing, and connections shall have
a design safe loading resistance of not less than 10 pounds per square
foot and no more than 20 pounds per square foot; or
(6)
Where wind loading values of the building code exceed 20 pounds per
square foot, the applicant shall submit a certification prepared and
sealed by a licensed professional engineer or licensed architect that:
(a)
The walls and partitions below the lowest floor have been designed
to collapse from a water load less than that which would occur during
the base flood.
(b)
The elevated portion of the building and supporting foundation
system have been designed to withstand the effects of wind and flood
loads acting simultaneously on all building components (structural
and nonstructural). Water loading values used shall be those associated
with the base flood; wind loading values used shall be those required
by the building code.
(c)
In Coastal A Zones, in addition to the requirements of this section, walls below the lowest floor shall have flood openings that meet the requirements of § 117-34C(3) of this section.
B.
For horizontal additions, whether structurally connected or not structurally
connected, to the base building:
(1)
If the addition combined with other proposed repairs, alterations, or modifications of the base building constitutes substantial improvement, the base building and the addition shall comply with the applicable requirements of Article IV of this chapter and this section.
(2)
If the addition constitutes substantial improvement, the base building and the addition shall comply with all of the applicable requirements of Article IV of this chapter and this section. [Note: The base building is required to comply. Otherwise it is an obstruction that does not comply with the free-of-obstruction requirement that applies to the elevated addition; see § 117-40B(3) of this chapter.]
C.
A horizontal addition to a building or structure that is not substantial
improvement is not required to comply with this section.
A.
Accessory structures shall be limited to not more than 600 square
feet in total floor area.
B.
Accessory structures shall comply with the elevation requirements and other requirements of § 117-40 of this chapter or, if not elevated, shall:
(1)
Be usable only for parking of vehicles or limited storage;
(2)
Be constructed with flood damage-resistant materials below the base
flood elevation;
(3)
Be constructed and placed to offer the minimum resistance to the
flow of floodwaters;
(4)
Be anchored to prevent flotation;
(5)
Have electrical service and mechanical equipment elevated to or above
the base flood elevation; and
(6)
If large than 100 square feet in size, have walls that meet the requirements of § 117-40D(3) through (6) of this chapter, as applicable for the flood zone; and if located in Coastal A Zones, walls shall have flood openings that meet the requirements of § 117-34C(3) of this chapter.
[Note: See NFIP Technical Bulletin #5, "Free-of-Obstruction
Requirements."]
A.
Decks and patios. In addition to the requirements of the building
code or the residential code, decks and patios shall be located, designed,
and constructed in compliance with the following:
(1)
A deck that is structurally attached to a building or structure shall
have the bottom of the lowest horizontal structural member at or above
the flood protection elevation and any supporting members that extend
below the design flood elevation shall comply with the foundation
requirements that apply to the building or structure, which shall
be designed to accommodate any increased loads resulting from the
attached deck.
(2)
A deck or patio that is located below the flood protection elevation
shall be structurally independent from structures and their foundation
systems, and shall be designed and constructed either to remain intact
and in place during base flood conditions or to break apart into small
pieces that will not cause structural damage to adjacent elevated
structures.
(3)
A deck or patio that has a vertical thickness of more than 12 inches
or that is constructed with more than the minimum amount of fill that
is necessary for site drainage shall not be approved unless an analysis
demonstrates no harmful diversion of floodwaters or wave runup and
wave reflection that would increase damage to adjacent elevated structures.
(4)
A deck or patio that has a vertical thickness of 12 inches or less
and that is at natural grade or on fill material that is similar to
and compatible with local soils and is the minimum amount necessary
for site drainage may be approved without requiring analysis of the
impact on diversion of floodwaters or wave runup and wave reflection.
B.
Other development. Other development activities shall be permitted
only if located outside the footprint of, and not structurally attached
to, structures, and only if an analysis demonstrates no harmful diversion
of floodwaters or wave runup and wave reflection onto adjacent elevated
structures. Other development includes but is not limited to:
