A. Designation of the local administrator. The Commissioner of the Building Department is hereby appointed local administrator to administer and implement this article by granting or denying floodplain development permits in accordance with its provisions.
B. Floodplain development permit.
(1) Purpose. A floodplain development permit is hereby established for all construction and other development to be undertaken in areas of special flood hazard in this community for the purpose of protecting its citizens from increased flood hazards and insuring that new development is constructed in a manner that minimizes its exposure to flooding. It shall be unlawful to undertake any development in an area of special flood hazard, as shown on the Flood Insurance Rate Map enumerated in § 350B, without a valid floodplain development permit. Application for a permit shall be made on forms furnished by the local, administrator and may include, but shall not be limited to, plans, in duplicate, drawn to scale and showing the nature, location, dimensions and elevations of the area in question; existing or proposed structures, fill, storage of materials, drainage facilities, and the location of the foregoing.
C. Fees. All applications for a floodplain development permit shall be accompanied by an application fee of $500. In addition, the applicant shall be responsible for reimbursing the Town of Hempstead for any additional costs necessary for review, inspection and approval of this project. The local administrator may require a deposit of no more than $500 to cover these additional costs.
D. Application for a permit. The applicant shall provide the following information as appropriate. Additional information may be required on the permit application form.
(1) The proposed elevation, in relation to mean sea level, of the lowest floor (including basement or cellar) of any new or substantially improved structure to be located in Zone A1-A30, AE or AH, or Zone A if base flood elevation data is available. Upon completion of the lowest floor, the permitee shall submit to the local administrator the as-built elevation, certified by a licensed professional engineer or surveyor.
(2) The proposed elevation, in relation to mean sea level, of the bottom of the lowest structural member of the lowest floor (excluding pilings and columns) of any new or substantially improved structure to be located in Zone V1-V30 or VE, or Zone V if base flood elevation data is available. Upon completion of the lowest floor, the permitee shall submit to the local administrator the as-built elevation, certified by a licensed professional engineer or surveyor.
(3) The proposed elevation, in relation to mean sea level, to which any new or substantially improved nonresidential structure will be floodproofed. Upon completion of the floodproofed portion of the structure, the permitee shall submit to the local administrator the as-built floodproofed elevation, certified by a professional engineer or surveyor.
(4) A certificate from a licensed professional engineer or architect that any utility floodproofing will meet the criteria in § 352B(3), Utilities.
(5) A certificate from a licensed professional engineer or architect that any nonresidential floodproofed structure will meet the floodproofing criteria in § 352E, Nonresidential structures (except coastal high-hazard areas).
(6) A description of the extent to which any watercourse will be altered or relocated as a result of proposed development. Computations by a licensed professional engineer must be submitted that demonstrate that the altered or relocated segment will provide equal or greater conveyance than the original stream segment. The applicant must submit any maps, computations or other material required by the Federal Emergency Management Agency (FEMA) to revise the documents enumerated in § 350B, when notified by the local administrator, and must pay any fees or other costs assessed by FEMA for this purpose. The applicant must also provide assurances that the conveyance capacity of the altered or relocated stream segment will be maintained.
(7) A technical analysis, by a licensed professional engineer, if required by the local administrator, which shows whether proposed development to be located in an area of special flood hazard may result in physical damage to any other property.
(8) In Zone A, when no base flood elevation data is available from other sources, base flood elevation data shall be provided by the permit applicant for subdivision proposals and other proposed developments (including proposals for manufactured home and recreational vehicle parks and subdivisions) that are greater than either 50 lots or five acres.
(9) In Zones V1-V30 and VE, and also Zone V if base flood elevation data is available, designs and specifications, certified by a licensed professional engineer or architect, for any breakaway walls in a proposed structure with design strengths in excess of 20 pounds per square foot.
(10) In Zones V1-V30 and VE, and also Zone V if base flood elevation data is available, for all new and substantial improvements to structures, floodplain development permit applications shall be accompanied by design plans and specifications, prepared in sufficient detail to enable independent review of the foundation support and connection components. Said plans and specifications shall be developed or reviewed by a licensed professional engineer or architect and shall be accompanied by a statement, bearing the signature of the architect or engineer, certifying that the design and methods of construction to be used are in accordance with accepted standards of practice and with all applicable provisions of this article.
E. Duties and responsibilities of the local administrator. Duties of the local administrator shall include but not be limited to the following:
(1) Permit application review: The local administrator shall conduct the following permit application review before issuing a floodplain development permit:
(a) Review all applications for completeness, particularly with the requirements of § 351D, Application for permit, and for compliance with the provisions and standards of this article.
(b) Review subdivision and other proposed new development, including manufactured home parks, to determine whether proposed building sites will be reasonably safe from flooding. If a proposed building site is located in an area of special flood hazard, all new construction and substantial improvements shall meet the applicable standards of § 352, Construction standards, and, in particular, § 352A(2), Subdivision proposals.
(c) Determine whether any proposed development in an area of special flood hazard may result in physical damage to any other property (e.g., stream bank erosion and increased flood velocities). The local administrator may require the applicant to submit additional technical analyses and data necessary to complete the determination. If the proposed development may result in physical damage to any other property or fails to meet the requirements of § 352, Construction standards, no permit shall be issued. The applicant may revise the application to include measures that mitigate or eliminate the adverse effects and resubmit the application.
(d) Determine that all necessary permits have been received from those governmental agencies from which approval is required by state or federal law.
(2) Use of other flood data:
(a) When the Federal Emergency Management Agency has designated areas of special flood hazard on the community's Flood Insurance Rate Map (FIRM) but has neither produced water surface elevation data (these areas are designated Zone A or V on the FIRM) nor identified a flood way, the local administrator shall obtain, review and reasonably utilize any base flood elevation and flood way data available from a federal, state or other source, including data developed pursuant to § 351D(7), as criteria for requiring that new construction, substantial improvements or other proposed development meets the requirements of this article.
(b) When base flood elevation data is not available, the local administrator may use flood information from any other authoritative source, such as historical data, to establish flood elevations within the areas of special flood hazard, for the purposes of this article.
(3) Alteration of watercourses:
(a) Notification to adjacent communities and the New York State Department of Environmental Conservation prior to permitting any alteration or relocation of a watercourse, and submittal of evidence of such notification to the Regional Director, Region II, Federal Emergency Management Agency.
(b) Determine that the permit holder has provided for maintenance within the altered or relocated portion of said watercourse so that the flood-carrying capacity is not diminished.
(4) Construction stage:
(a) In Zones A1-A30, AE and AH, and also Zone A if base flood elevation data is available, upon placement of the lowest floor or completion of floodproofing of a new or substantially improved structure, obtain from the permit holder a certification of the as-built elevation of the lowest floor or floodproofed elevation, in relation to mean sea level. The certificate shall be prepared by or under the direct supervision of a licensed land surveyor or professional engineer and certified by same. For manufactured homes, the permit holder shall submit the certificate of elevation upon placement of the structure on the site. A certificate of elevation must also be submitted for a recreational vehicle if it remains on a site for 180 consecutive days or longer (unless it is fully licensed and ready for highway use).
(b) In Zones V1-V30 and VE, and also Zone V if base flood elevation data is available, upon placement of the lowest floor of a new or substantially improved structure, the permit holder shall submit to the local administrator a certificate of elevation, in relation to mean sea level, of the bottom of the lowest structural member of the lowest floor (excluding pilings and columns). The certificate shall be prepared by or under the direct supervision of a licensed land surveyor or professional engineer and certified by same. For manufactured homes, the permit holder shall submit the certificate of elevation upon placement of the structure on the site. An elevation certificate must also be submitted for a recreational vehicle if it remains on a site 180 consecutive days or longer (unless it is fully licensed and ready for highway use).
(c) Any further work undertaken prior to submission and approval of the certification shall be at the permit holder's risk. The local administrator shall review all data submitted. Deficiencies detected shall be cause to issue a stop-work order for the project unless immediately corrected.
(5) Inspections: The local administrator and/or the developer's engineer or architect shall make periodic inspections at appropriate times throughout the period of construction in order to monitor compliance with permit conditions and enable said inspector to certify, if requested, that the development is in compliance with the requirements of the floodplain development permit and/or any variance provisions.
(6) Stop-work orders:
(a) The local administrator shall issue, or cause to be issued, a stop work order for any floodplain development found ongoing without a development permit. Disregard of a stop-work order shall subject the violator to the penalties described in § 350E of this article.
(b) The local administrator shall issue, or cause to be issued, a stop work order for any floodplain development found noncompliant with the provisions of this article and/or the conditions of the development permit. Disregard of a stop-work order shall subject the violator to the penalties described in § 350E of this article.
(7) Certificate of compliance.
(a) In areas of special flood hazard, as determined by documents enumerated in § 350B, it shall be unlawful to occupy or to permit the use or occupancy of any building or premises, or both, or part thereof hereafter created, erected, changed, converted or wholly or partly altered or enlarged in its use or structure until a certificate of compliance has been issued by the local administrator stating that the building or land conforms to the requirements of this article.
(b) A certificate of compliance shall be issued by the local administrator upon satisfactory completion of all development in areas of special flood hazard.
(c) Issuance of the certificate shall be based upon the inspections conducted as prescribed in § 351E(5), Inspections, and/or any certified elevations, hydraulic data, floodproofing, anchoring requirements or encroachment analyses which may have been required as a condition of the approved permit.
(8) Information to be retained. The local administrator shall retain, and make available for inspection, copies of the following:
(a) Floodplain development permits and certificates of compliance;
(b) Certifications of as-built lowest floor elevations of structures, required pursuant to § 351E(4)(a) and (b), and whether or not the structures contain a basement;
(c) Floodproofing certificates required pursuant to § 351E(4)(a), and whether or not the structures contain a basement;
(d) Variances issued pursuant to § 353, Variance procedures; and
(e) Notices required under § 351E(3), Alteration of watercourses.
A. General standards. 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 § 350B.
(1) Coastal high-hazard areas. The following requirements apply within Zones V1-V30, VE and V:
(a) 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.
(b) The use of fill for structural support of buildings, manufactured homes or recreational vehicles on site 180 days or longer is prohibited.
(c) Man-made alteration of sand dunes, which would increase potential flood damage, is prohibited.
(2) Subdivision 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):
(a) Proposals shall be consistent with the need to minimize flood damage;
(b) Public utilities and facilities such as sewer, gas, electrical and water systems shall be located and constructed so as to minimize flood damage; and
(c) Adequate drainage shall be provided to reduce exposure to flood damage.
(3) Encroachments.
(a) Within Zones Al-A30 and AE, on streams without a regulatory flood way, no new construction, substantial improvements or other development (including fill) shall be permitted unless:
[1] 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
[2] The Town of Hempstead 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 Hempstead 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 Hempstead for all costs related to the final map revision.
(b) On streams with a regulatory flood way, as shown on the Flood Boundary and Flood way Map or the Flood Insurance Rate Map adopted in § 350B, no new construction, substantial improvements or other development in the flood way (including fill) shall be permitted unless:
[1] A technical evaluation by a licensed professional engineer shows that such an encroachment shall not result in any increase in flood levels during occurrence of the base flood; or
[2] The Town of Hempstead agrees to apply to the Federal Emergency Management Agency (FEMA) for a conditional FIRM and flood way revision, FEMA approval is received and the applicant provides all necessary data, analyses and mapping and reimburses the Town of Hempstead 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 Hempstead for all costs related to the final map revisions.
B. Standards for all structures.
(1) 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.
(2) Construction materials and methods.
(a) New construction and substantial improvements to structures shall be constructed with materials and utility equipment resistant to flood damage.
(b) New construction and substantial improvements to structures shall be constructed using methods and practices that minimize flood damage.
(c) Enclosed areas.
[1] For enclosed areas below the lowest floor of a structure within Zone A1-A30, AE or AH, and also Zone A if base flood elevation data is available, 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 having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding; and
[b] The bottom of all such openings no higher than one foot above the lowest adjacent finished grade.
[2] Openings may be equipped with louvers, valves, screens or other coverings or devices, provided they permit the automatic entry and exit of floodwaters.
[3] Enclosed areas subgrade on all sides are considered basements and are not permitted.
(d) Within Zones V1-V30 and VE, and also within Zone V if base flood elevation data is 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.
(3) Utilities.
(a) New and replacement electrical equipment, heating, ventilating, air conditioning, plumbing connections, and other service equipment shall be located at or above the base flood elevation or shall 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 to or above the base flood elevation 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;
(b) New and replacement water supply systems shall be designed to minimize or eliminate infiltration of floodwaters into the system;
(c) 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; and
(d) On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.
C. Residential structures (except coastal high-hazard areas).
(1) Elevation. The following standards apply to new and substantially improved residential structures located in areas of special flood hazard, in addition to the requirements in § 352A(2), Subdivision proposals, and § 352A(3), Encroachments, and § 352B, Standards for all structures.
(a) Within Zones A1-A30, AE and AH, and also Zone A if base flood elevation data is available, new construction and substantial improvements shall have the lowest floor (including basement) elevated to or above two feet above the base flood elevation.
(b) Within Zone A, when no base flood elevation data is available, new and substantially improved structures shall have the lowest floor (including basement) elevated at least three feet above the highest adjacent grade.
(c) Within Zone AO, new and substantially improved structures shall have the lowest floor (including basement) elevated above the highest adjacent grade at least as high as two feet above the depth number specified in feet on the community's Flood Insurance Rate Map enumerated in § 350B (at least two feet if no depth number is specified).
(d) Within Zones AH and AO, adequate drainage paths are required to guide floodwaters around and away from proposed structures on slopes.
D. Residential structures (coastal high-hazard areas). The following standards, in addition to the standards in § 352A(1), Coastal high-hazard areas, and § 352A(2), Subdivision proposals, and § 35213, Standards for all structures, apply to new and substantially improved residential structures located in areas of special flood hazard shown as Zone V1-V30, VE or V on the community's Flood Insurance Rate Map designated in § 35013.
(1) 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.
(2) 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.
(a) 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 runup beyond the elevation of the base flood.
(b) 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.
(c) Wind loading values used shall be those required by the Building Code.
(3) Foundation standards.
(a) 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).
(b) Spread footings and fill material shall not be used for structural support of a new building or substantial improvement of an existing structure.
(4) Pile foundation design.
(a) 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.
(b) 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 5 feet below mean sea level (msl) datum if the BFE (base flood elevation) is +10 msl or less or shall be at least 10 feet below msl if the BFE is greater than +10 msl.
(c) 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.
(d) 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.
(e) Reinforced concrete piles shall be cast of concrete having a 28 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.
(f) Piles shall be driven by means of a pile driver or drop hammer, jetted or augered into place.
(g) Additional support for piles in the form of bracing may include lateral or diagonal bracing between piles.
(h) 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.
(i) 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 shall be 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.
(j) 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 pilelbeam, or four-by-four or larger braces framed into the pile/beam. Bolting shall consist of two 5/8-inch galvanized-steel bolts (each end) for two by eight members, or one 5/8-inch lag bolt (each end) for square members. Knee braces shall not extend more than three feet below the elevation of the base flood.
(5) Column foundation design.
(a) Masonry piers or poured-in-place concrete piers shall be internally reinforced to resist vertical and lateral loads and shall be connected with a movement-resisting connection to a pile cap or pile shaft.
(6) Connectors and fasteners.
(a) 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.
(b) Toe nailing as a principal method of connection is not permitted.
(c) 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.
(7) Beam-to-pile connections.
(a) 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, if 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 5/8-inch galvanized steel bolts or two hot dipped galvanized straps 3/16 inch by four inches by 18 inches each bolted with two 1/2-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%.
(8) Floor and deck connections.
(a) 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.
(b) 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 3/4 inch in 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.
(9) Exterior wall connections.
(a) 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 1/2 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 1/2-inch-round rods. These anchors shall be installed no more than two feet from each corner rod, no more than four feet on center.
(10) Ceiling joist/rafter connections.
(a) 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.
(b) 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.
(11) Projecting members.
(a) 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.
(b) Larger overhangs and porches will be permitted if designed or reviewed and certified by a registered professional engineer or architect.
(12) Roof sheathing.
(a) 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 shall be of other suitable corrosion-resistant material.
(b) 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.
(c) 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
(13) Protection of openings.
(a) 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.
(14) Breakaway wall design standards.
(a) 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.
(b) 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 the breakaway walls will fail under water loads less than those that would occur during the base flood and 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.
E. Nonresidential structures (except coastal high-hazard areas). 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 § 352A(2), Subdivision proposals, and § 352A(3), Encroachments, and § 352B, Standards for all structures.
(1) Within Zones A1-A30, AE and AH, and also Zone A if base flood elevation data is available, new construction and substantial improvements of any nonresidential structure, together with attendant utility and sanitary facilities, shall either:
(a) Have the lowest floor, including basement or cellar, elevated to or above two feet above the base flood elevation; or
(b) Be floodproofed so that the structure is watertight below two feet above the base flood elevation, 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.
(2) Within Zone AO, new construction and substantial improvements of nonresidential structures shall:
(a) Have the lowest floor (including basement) elevated above the highest adjacent grade at least as high as two feet above the depth number specified in feet on the community's FIRM (at least two feet if no depth number is specified); or
(b) Together with attendant utility and sanitary facilities, be completely floodproofed to that level to meet the floodproofing standard specified in § 352B(3).
(3) 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 § 352-E(1)(b), including the specific elevation (in relation to mean sea level) to which the structure is to be floodproofed.
(4) Within Zones AH and AO, adequate drainage paths are required to guide floodwaters around and away from proposed structures on slopes.
(5) Within Zone A, when no base flood elevation data is available, the lowest floor (including basement) shall be elevated at least three feet above the highest adjacent grade.
F. Nonresidential structures (coastal high-hazard areas).
(1) In Zones V1-V30 and VE, and also Zone V if base flood elevation data is available, new construction and substantial improvements of any nonresidential structure, together with attendant utility and sanitary facilities, shall have the bottom of the 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.
G. Manufactured homes and recreational vehicles. The following standards, in addition to the standards in § 352A, General standards, and § 352B, 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.
(1) Recreational vehicles.
(a) Recreational vehicles placed on sites within Zones A1-A30, AE, AH, V1-V30, V, and VE shall either:
[1] Be on site fewer than 180 consecutive days;
[2] Be fully licensed and ready for highway use; or
[3] Meet the requirements for manufactured homes in § 352G(2), (3) and (4).
(b) A recreational vehicle is ready for highway use if it is on its wheels or jacking system, is attached to the site only by quick-disconnect-type utilities and security devices and has no permanently attached additions.
(2) A manufactured home that is placed or substantially improved in Zones A1-A30, AE, AH, Vl-V30, V, and VE shall be elevated on a permanent foundation such that the lowest floor is elevated to or above two feet above the base flood elevation and is securely anchored to an adequately anchored foundation system to resist flotation, collapse and lateral movement. Elevation on piers consisting of dry stacked blocks is prohibited.
(3) Within Zone A or V, when no base flood elevation data is available, new and substantially improved manufactured homes shall be elevated such that the manufactured home chassis is supported by reinforced piers or other foundation elements of at least equivalent strength that are no less than 36 inches in height above grade and are securely anchored to an adequately anchored foundation system to resist flotation, collapse or lateral movement. Elevation on piers consisting of dry stacked blocks is prohibited.
(4) Within Zone AO, the floor shall be elevated above the highest adjacent grade at least as high as the depth number specified on the Flood Insurance Rate Map enumerated in § 350B (at least two feet if no depth number is specified). Elevation on piers consisting of dry stacked blocks is prohibited.
