The following standards apply to new development, including new and substantially improved structures, in the areas of special flood hazard shown on the Flood Insurance Rate Map designated in § 113-6:
A.
Coastal high-hazard areas and Coastal A Zones. The following requirements
apply within Zones V1-V30, VE and V:
(1)
All new construction, including manufactured homes and recreational
vehicles on-site 180 days or longer and not fully licensed for highway
use, shall be located landward of the reach of high tide.
(2)
The use of fill for structural support of buildings, manufactured
homes or recreational vehicles on-site 180 days or longer is prohibited.
(3)
Man-made alteration of sand dunes which would increase potential
flood damage is prohibited.
B.
Subdivision and development proposals. The following standards apply
to all new subdivision proposals and other proposed development in
areas of special flood hazard (including proposals for manufactured
home and recreational vehicle parks and subdivisions):
(1)
Proposals shall be consistent with the need to minimize flood damage.
(2)
Public utilities and facilities such as sewer, gas, electrical and
water systems shall be located and constructed to minimize flood damage.
(3)
Adequate drainage shall be provided to reduce exposure to flood damage.
(4)
Proposed development shall not result in physical damage to any other
property (e.g., stream bank erosion or increased flood velocities).
If requested by the local administrator, the applicant shall provide
a technical analysis, by a licensed professional engineer, demonstrating
that this condition has been met.
(5)
Proposed development shall be designed, located, and constructed
so as to offer the minimum resistance to the flow of water and shall
be designed to have a minimum effect upon the height of floodwater.
(6)
Any equipment or materials located in a special flood hazard area
shall be elevated, anchored, and floodproofed as necessary to prevent
flotation, flood damage, and the release of hazardous substances.
(7)
No alteration or relocation of a watercourse shall be permitted unless:
(a)
A technical evaluation by a licensed professional engineer demonstrates
that the altered or relocated segment will provide conveyance equal
to or greater than that of the original stream segment and will not
result in physical damage to any other property;
(b)
If warranted, a conditional revision of the Flood Insurance
Rate Map is obtained from the Federal Emergency Management Agency,
with the applicant providing the necessary data, analyses, and mapping
and reimbursing the Town of Evans for all fees and other costs in
relation to the application; and
(c)
The applicant provides assurance that maintenance will be provided
so that the flood-carrying capacity of the altered or relocated portion
of the watercourse will not be diminished.
C.
Encroachments.
(1)
Within Zones A1-A30 and AE, on streams without a regulatory floodway,
no new construction, substantial improvements or other development
(including fill) shall be permitted unless:
(a)
The applicant demonstrates 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 location; or
(b)
The Town of Evans agrees to apply to the Federal Emergency Management
Agency (FEMA) for a conditional FIRM revision, FEMA approval is received
and the applicant provides all necessary data, analyses and mapping
and reimburses the Town of Evans for all fees and other costs in relation
to the application. The applicant must also provide all data, analyses
and mapping and reimburse the Town of Evans for all costs related
to the final map revision.
(2)
On streams with a regulatory floodway, as shown on the Flood Boundary and Floodway Map or the Flood Insurance Rate Map adopted in § 113-6, no new construction, substantial improvements or other development in the floodway (including fill) shall be permitted unless:
(a)
A technical evaluation by a licensed professional engineer demonstrates
through hydrologic and hydraulic analyses performed in accordance
with standard engineering practice that such an encroachment shall
not result in any increase in flood levels during occurrence of the
base flood; or
(b)
The Town of Evans agrees to apply to the Federal Emergency Management
Agency (FEMA) for a conditional FIRM and floodway revision, FEMA approval
is received and the applicant provides all necessary data, analyses
and mapping and reimburses the Town of Evans for all fees and other
costs in relation to the application. The applicant must also provide
all data, analyses and mapping and reimburse the Town of Evans for
all costs related to the final map revisions.
(3)
In Zones A1-A30, AE and AH, and also Zone A if base flood elevation
data are available, if any development is found to increase or decrease
base flood elevations, the Town of Evans shall as soon as practicable,
but not later than six months after the date such information becomes
available, notify FEMA and the New York State Department of Environmental
Conservation of the changes by submitting technical or scientific
data in accordance with standard engineering practice.
The following standards apply to new development, including new and substantially improved structures, in the areas of special flood hazard shown on the Flood Insurance Rate Map designated in § 113-6:
A.
Anchoring. New structures and substantial improvement to structures
in areas of special flood hazard shall be anchored to prevent flotation,
collapse, or lateral movement during the base flood. This requirement
is in addition to applicable state and local anchoring requirements
for resisting wind forces.
B.
Construction materials and methods.
(1)
New construction and substantial improvements to structures shall
be constructed with materials and utility equipment resistant to flood
damage.
(2)
New construction and substantial improvements to structures shall
be constructed using methods and practices that minimize flood damage.
(3)
For enclosed areas below the lowest floor of a structure within Zones
A1-A30, AE, AO or A, new and substantially improved structures shall
have fully enclosed areas below the lowest floor that are usable solely
for parking of vehicles, building access or storage in an area other
than a basement and which are subject to flooding, designed to automatically
equalize hydrostatic flood forces on exterior walls by allowing for
the entry and exit of floodwaters. Designs for meeting this requirement
must either be certified by a licensed professional engineer or architect
or meet or exceed the following minimum criteria:
(a)
A minimum of two openings of each enclosed area having a total
net area of not less than one square inch for every square foot of
enclosed area subject to flooding.
(b)
The bottom of all such openings no higher than one foot above
grade.
(c)
Openings not less than three inches in any direction. Openings
may be equipped with louvers, valves, screens or other coverings or
devices, provided they permit the automatic entry and exit of floodwaters.
Enclosed areas subgrade on all sides are considered basements and
are not permitted.
(4)
Within Zones V1-V30 and VE, and also within Zone V if base flood
elevation are available, new construction and substantial improvements
shall have the space below the lowest floor either free from obstruction
or constructed with nonsupporting breakaway walls, open wood lattice-work
or insect screening intended to collapse under wind and water loads
without causing collapse, displacement, or other structural damage
to the elevated portion of the building or supporting foundation system.
The enclosed space below the lowest floor shall be used only for parking
vehicles, building access or storage. Use of this space for human
habitation is expressly prohibited. The construction of stairs, stairwells
and elevator shafts are subject to the design requirements for breakaway
walls.
C.
Utilities.
(1)
New and replacement electrical equipment, heating, ventilating, air
conditioning, plumbing connections, and other service equipment shall
be located at least two feet above the base flood elevation, or be
designed to prevent water from entering and accumulating within the
components during a flood and to resist hydrostatic and hydrodynamic
loads and stresses. Electrical wiring and outlets, switches, junction
boxes and panels shall be elevated or designed to prevent water from
entering and accumulating within the components unless they conform
to the appropriate provisions of the electrical part of the Building
Code of New York State or the Residential Code of New York State for
location of such items in wet locations.
(2)
New and replacement water supply systems shall be designed to minimize
or eliminate infiltration of floodwaters into the system.
(3)
New and replacement sanitary sewage systems shall be designed to
minimize or eliminate infiltration of floodwaters. Sanitary sewer
and storm drainage systems for buildings that have openings below
the base flood elevation shall be provided with automatic backflow
valves or other automatic backflow devices that are installed in each
discharge line passing through a building's exterior wall.
(4)
On-site waste disposal systems shall be located to avoid impairment
to them or contamination from them during flooding.
The following standards apply to new and substantially improved residential structures located in areas of special flood hazard, in addition to the requirements in § 113-15B, Subdivision and development proposals; § 113-15C, Encroachments; and § 113-16, Standards for all structures:
A.
Within Zones A1-A30, AE and AH, and also Zone A if base flood elevation
data are available, new construction and substantial improvements
shall have the top of the lowest floor (including basement) elevated
to or above two feet above the base flood elevation. Within Zones
AH, adequate drainage paths are required to guide floodwaters around
and away from proposed structures on slopes.
B.
Within Zone A, when no base flood elevation data are available, a
base flood elevation shall be determined by either:
(1)
Obtaining and reasonably using data available from a federal, state,
or other source, plus two feet of freeboard; or
(2)
Determining the base flood elevation in accordance with accepted
hydrologic and hydraulic engineering practice, plus two feet of freeboard.
Determinations shall be undertaken by a registered design professional
who shall document that the technical methods used reflect currently
accepted engineering practice. Studies, analyses, and computations
shall be submitted in sufficient detail to allow thorough review and
approval.
C.
Within Zone AO, new construction and substantial improvements shall have the lowest floor (including basement) elevated above the highest adjacent grade at least as high as the depth number specified in feet on the community's Flood Insurance Rate Map enumerated in § 113-6, plus one foot of freeboard. In areas designated as Zone AO where a depth number is not specified on the map, the depth number shall be taken as being equal to two feet. Within AO, adequate drainage paths are required to guide floodwaters around and away from proposed structures on slopes.
The following standards, in addition to the standards in § 113-15A, Coastal high-hazard areas and Coastal A Zones; § 113-15B, Subdivision and development proposals; and § 113-16, Standards for all structures, apply to new and substantially improved residential structures located in areas of special flood hazard shown as Zones V1-V30, VE or V on the community's Flood Insurance Rate Map designated in § 113-6:
A.
Elevation. New construction and substantial improvements shall be
elevated on pilings, columns or shear walls such that the bottom of
the lowest horizontal structural member supporting the lowest elevated
floor (excluding columns, piles, diagonal bracing attached to the
piles or columns, grade beams, pile caps and other members designed
to either withstand storm action or break away without imparting damaging
loads to the structure) is elevated to or above two feet above base
flood elevation so as not to impede the flow of water.
B.
Determination of loading forces. Structural design shall consider
the effects of wind and water loads acting simultaneously during the
base flood on all building components.
(1)
The structural design shall be adequate to resist water forces that
would occur during the base flood. Horizontal water loads considered
shall include inertial and drag forces of waves, current drag forces,
and impact forces from waterborne storm debris. Dynamic uplift loads
shall also be considered if bulkheads, walls, or other natural or
man-made flow obstructions could cause wave run-up beyond the elevation
of the base flood.
(2)
Buildings shall be designed and constructed to resist the forces
due to wind pressure. Wind forces on the superstructure include windward
and leeward forces on vertical walls, uplift on the roof, internal
forces when openings allow wind to enter the house, and upward force
on the underside of the house when it is exposed. In the design, the
wind should be assumed to blow potentially from any lateral direction
relative to the house.
(3)
Wind loading values used shall be those required by the building
code.
C.
Foundation standards.
(1)
The pilings or column foundation and structure attached thereto shall
be adequately anchored to resist flotation, collapse or lateral movement
due to the effects of wind and water pressures acting simultaneously
on all building components. Foundations must be designed to transfer
safely to the underlying soil all loads due to wind, water, dead load,
live load and other loads (including uplift due to wind and water).
(2)
Spread footings and fill material shall not be used for structural
support of a new building or substantial improvement of an existing
structure.
D.
Pile foundation design.
(1)
The design ratio of pile spacing to pile diameter shall not be less
than 8:1 for individual piles (this shall not apply to pile clusters
located below the design grade). The maximum center-to-center spacing
of wood piles shall not be more than 12 feet on center under load-bearing
sills, beams, or girders.
(2)
Pilings shall have adequate soil penetration (bearing capacity) to
resist the combined wave and wind loads (lateral and uplift) associated
with the base flood acting simultaneously with typical structure (live
and dead) loads, and shall include consideration of decreased resistance
capacity caused by erosion of soil strata surrounding the piles. The
minimum penetration for foundation piles is to an elevation of five
feet below mean sea level (msl) datum if the BFE is +10 msl or less,
or to be at least 10 feet below msl if the BFE is greater than +10
msl.
(3)
Pile foundation analysis shall also include consideration of piles
in column action from the bottom of the structure to the stable soil
elevation of the site. Pilings may be horizontally or diagonally braced
to withstand wind and water forces.
(4)
The minimum acceptable sizes for timber piles are a tip diameter
of eight inches for round timber piles and eight inches by eight inches
for square timber piles. All wood piles must be treated in accordance
with requirements of EPEE-C3 to minimize decay and damage from fungus.
(5)
Reinforced concrete piles shall be cast of concrete having a twenty-eight-day
ultimate compressive strength of not less than 5,000 pounds per square
inch, and shall be reinforced with a minimum of four longitudinal
steel bars having a combined area of not less than 1% nor more than
4% of the gross concrete area. Reinforcing for precast piles shall
have a concrete cover of not less than 1 1/4 inches for No. 5
bars and smaller and not less than 1 1/2 inches for No. 6 through
No. 11 bars. Reinforcement for piles cast in the field shall have
a concrete cover of not less than two inches.
(6)
Piles shall be driven by means of a pile driver or drop hammer, jetted,
or augered into place.
(7)
Additional support for piles in the form of bracing may include lateral
or diagonal bracing between piles.
(8)
When necessary, piles shall be braced at the ground line in both
directions by a wood timber grade beam or a reinforced concrete grade
beam. These at-grade supports should be securely attached to the piles
to provide support even if scoured from beneath.
(9)
Diagonal bracing between piles, consisting of two-inch by eight-inch
(minimum) members bolted to the piles, shall be limited in location
to below the lowest supporting structural member and above the stable
soil elevation, and aligned in the vertical plane along pile rows
perpendicular to the shoreline. Galvanized steel rods (minimum diameter
1/2 inch) or cable-type bracing is permitted in any plane.
(10)
Knee braces, which stiffen both the upper portion of a pile
and the beam-to-pile connection, may be used along pile rows perpendicular
and parallel to the shoreline. Knee braces shall be two-by-eight lumber
bolted to the sides of the pile/beam, or four-by-four or larger braces
framed into the pile/beam. Bolting shall consist of two five-eighths-inch
galvanized steel bolts (each end) for two-by-eight members, or one
five-eighths-inch lag bolt (each end) for square members. Knee braces
shall not extend more than three feet below the elevation of the base
flood.
E.
Column foundation design. Masonry piers or poured-in-place concrete
piers shall be internally reinforced to resist vertical and lateral
loads, and be connected with a movement-resisting connection to a
pile cap or pile shaft.
F.
Connectors and fasteners. Galvanized metal connectors, wood connectors,
or bolts of size and number adequate for the calculated loads must
be used to connect adjoining components of a structure. Toe nailing
as a principal method of connection is not permitted. All metal connectors
and fasteners used in exposed locations shall be steel, hot-dipped
galvanized after fabrication. Connectors in protected interior locations
shall be fabricated from galvanized sheet.
G.
Beam-to-pile connections. The primary floor beams or girders shall
span the supports in the direction parallel to the flow of potential
floodwater and wave action and shall be fastened to the columns or
pilings by bolting, with or without cover plates. Concrete members
shall be connected by reinforcement, if cast in place, or (of precast)
shall be securely connected by bolting and welding. If sills, beams,
or girders are attached to wood piling at a notch, a minimum of two
five-eighths-inch galvanized steel bolts or two hot-dipped galvanized
straps 3/16 inch by four inches by 18 inches, each bolted with two
one-half-inch lag bolts per beam member, shall be used. Notching of
pile tops shall be the minimum sufficient to provide ledge support
for beam members without unduly weakening pile connections. Piling
shall not be notched so that the cross section is reduced below 50%.
H.
Floor and deck connections.
(1)
Wood two-inch-by-four-inch (minimum) connectors or metal joist anchors
shall be used to tie floor joists to floor beams/girders. These should
be installed on alternate floor joists, at a minimum. Cross bridging
of all floor joists shall be provided. Such cross bridging may be
one-inch-by-three-inch members, placed eight feet on-center maximum,
or solid bridging of same depth as joist at same spacing.
(2)
Plywood should be used for subflooring and attic flooring to provide
good torsional resistance in the horizontal plane of the structure.
The plywood should not be less than three-fourths-inch total thickness,
and should be exterior grade and fastened to beams or joists with
8d annular or spiral thread galvanized nails. Such fastening shall
be supplemented by the application of waterproof industrial adhesive
applied to all bearing surfaces.
I.
Exterior wall connections. All bottom plates shall have any required
breaks under a wall stud or an anchor bolt. Approved anchors will
be used to secure rafters or joists and top and bottom plates to studs
in exterior and bearing walls to form a continuous tie. Continuous
15/32-inch or thicker plywood sheathing, overlapping the top wall
plate and continuing down to the sill, beam, or girder, may be used
to provide the continuous tie. If the sheets of plywood are not vertically
continuous, then two-by-four nailer blocking shall be provided at
all horizontal joints. In lieu of the plywood, galvanized steel rods
of one-half-inch diameter or galvanized steel straps not less than
one inch wide by 1/16 inch thick may be used to connect from the top
wall plate to the sill, beam, or girder. Washers with a minimum diameter
of three inches shall be used at each end of the one-half-inch round
rods. These anchors shall be installed no more than two feet from
each corner rod, no more than four feet on center.
J.
Ceiling joist/rafter connections.
(1)
All ceiling joists or rafters shall be installed in such a manner
that the joists provide a continuous tie across the rafters. Ceiling
joists and rafters shall be securely fastened at their intersections.
A metal or wood connector shall be used at alternate ceiling joist/rafter
connections to the wall top plate.
(2)
Gable roofs shall be additionally stabilized by installing two-by-four
blocking on two-foot centers between the rafters at each gable end.
Blocking shall be installed a minimum of eight feet toward the house
interior from each gable end.
K.
Projecting members. All cantilevers and other projecting members
must be adequately supported and braced to withstand wind and water
uplift forces. Roof eave overhangs shall be limited to a maximum of
two feet and joist overhangs to a maximum of one foot. Larger overhangs
and porches will be permitted if designed or reviewed and certified
by a registered professional engineer or architect.
L.
Roof sheathing.
(1)
Plywood, or other wood material, when used as roof sheathing, shall
not be less than 15/32 inch in thickness, and shall be of exterior
sheathing grade or equivalent. All attaching devices for sheathing
and roof coverings shall be galvanized or be of other suitable corrosion-resistant
material.
(2)
All corners, gable ends, and roof overhangs exceeding six inches
shall be reinforced by the application of waterproof industrial adhesive
applied to all bearing surfaces of any plywood sheet used in the sheathing
of such corner, gable end, or roof overhang.
(3)
In addition, roofs should be sloped as steeply as practicable to
reduce uplift pressures, and special care should be used in securing
ridges, hips, valleys, eaves, vents, chimneys, and other points of
discontinuity in the roofing surface.
M.
Protection of openings. All exterior glass panels, windows, and doors
shall be designed, detailed, and constructed to withstand loads due
to the design wind speed of 75 miles per hour. Connections for these
elements must be designed to transfer safely the design loads to the
supporting structure. Panel widths of multiple-panel sliding glass
doors shall not exceed three feet.
N.
Breakaway wall design standards.
(1)
The breakaway wall shall have a design safe loading resistance of
not less than 10 and not more than 20 pounds per square foot, with
the criterion that the safety of the overall structure at the point
of wall failure be confirmed using established procedures. Grade beams
shall be installed in both directions for all piles considered to
carry the breakaway wall load. Knee braces are required for front
row piles that support breakaway walls.
(2)
Use of breakaway wall strengths in excess of 20 pounds per square
foot shall not be permitted unless a registered professional engineer
or architect has developed or reviewed the structural design and specifications
for the building foundation and breakaway wall components, and certifies
that 1) the breakaway walls will fail under water loads less than
those that would occur during the base flood; and 2) the elevated
portion of the building and supporting foundation system will not
be subject to collapse, displacement, or other structural damage due
to the effects of wind and water 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 shall be those required by the building code.
The following standards apply to new and substantially improved commercial, industrial and other nonresidential structures located in areas of special flood hazard, in addition to the requirements in § 113-15B, Subdivision and development proposals; § 113-15C, Encroachments; and § 113-16, Standards for all structures:
A.
Within Zones A1-A30, AE and AH, and also Zone A if base flood elevation
data are available, new construction and substantial improvements
of any nonresidential structure, together with attendant utility and
sanitary facilities, shall either:
(1)
Have the lowest floor, including basement or cellar, elevated to
or above two feet above the base flood elevation; or
(2)
Be floodproofed so that the structure is watertight below two feet
above the base flood elevation, including attendant utility and sanitary
facilities, with walls substantially impermeable to the passage of
water. All structural components located below the base flood elevation
must be capable of resisting hydrostatic and hydrodynamic loads and
the effects of buoyancy.
B.
Within Zone AO, new construction and substantial improvements of
nonresidential structures shall:
(1)
Have the lowest floor (including basement) elevated above the highest
adjacent grade at least as high as the depth number specified in feet
on the community's FIRM plus two feet (at least three feet if
no depth number is specified); or
C.
If the structure is to be floodproofed, a licensed professional engineer or architect shall develop and/or review structural design, specifications, and plans for construction. A floodproofing certificate or other certification shall be provided to the local administrator that certifies the design and methods of construction are in accordance with accepted standards of practice for meeting the provisions of Subsection A(2), including the specific elevation (in relation to mean sea level) to which the structure is to be floodproofed.
D.
Within Zones AH and AO, adequate drainage paths are required to guide
floodwaters around and away from proposed structures on slopes.
E.
Within Zone A, when no base flood elevation data are available, the
lowest floor (including basement) shall be elevated at least three
feet above the highest adjacent grade.
In Zones V1-V30, VE and also Zone V if base flood elevations
are available, new construction and substantial improvements of any
nonresidential structure, together with attendant utility and sanitary
facilities, shall have the bottom of lowest member of the lowest floor
elevated to or above two feet above the base flood elevation. Floodproofing
of structures is not an allowable alternative to elevating the lowest
floor to two feet above the base flood elevation in Zones V1-V30,
VE and V.
The following standards, in addition to the standards in § 113-15, General standards, and § 113-16, Standards for all structures, apply, as indicated, in areas of special flood hazard to manufactured homes and to recreational vehicles which are located in areas of special flood hazard:
A.
B.
Within Zones A1-A30, AE, and AH, the bottom of the frame of the manufactured home shall be elevated to meet the requirements of § 113-17A. Elevation on piers consisting of dry stacked blocks is prohibited.
C.
Within Zone A, the bottom of the frame of the manufactured home shall be elevated to meet the requirements of § 113-17B. Elevation on piers consisting of dry stacked blocks is prohibited.
D.
Within Zone AO, the bottom of the frame of the manufactured home shall be elevated to meet the requirements of § 113-17C. Elevation on piers consisting of dry stacked blocks is prohibited.
F.
The foundation and anchorage of manufactured homes to be located
in identified floodways shall be designed and constructed in accordance
with ASCE 24.
The following standards apply to new and substantially improved accessory structures, including detached garages, in the areas of special flood hazard shown on the Flood Insurance Rate Map designated in § 113-6.
A.
Within Zones A1-A30, AE, AO, AH, and A, accessory structures must meet the standards of § 113-16A, Anchoring,
B.
Within Zones A1-A30, AE and AH, and also Zone A if base flood elevation
data are available, areas below two feet above the base flood elevation
shall be constructed using methods and practices that minimize flood
damage.
C.
Within Zones AO and A, if base flood elevation data are not available,
areas below three feet above the highest adjacent grade shall be constructed
using methods and practices that minimize flood damage.
D.
Structures must be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters in accordance with § 113-16C, Utilities.
E.
Within Zones V1-V30, VE, and V, accessory structures (unless properly
elevated to the base flood elevation plus two feet on piles or columns)
must be limited to small, low-value structures that are disposable.
If a community wishes to allow unelevated accessory buildings, it
must define "small" and "low cost."
F.
Within Zones V1-V30, VE, and V, Unelevated accessory buildings must
be unfinished inside, constructed with flood-resistant materials,
and used only for storage.
G.
Within Zones V1-V30, VE, and V, when an accessory building is placed,
the design professional must determine the effect that debris from
the accessory building will have on nearby buildings. If the accessory
building is large enough that its failure could create damaging debris
or divert flood flows, it must be elevated above the base flood elevation,
plus two feet.
