(A) Residential construction. New construction and substantial improvement of any residential structure (including manufactured homes) shall have the reference level, including basement, elevated no lower than the regulatory flood protection elevation, as defined in § 154.05 of this chapter.
(B) Non-residential construction. New construction and substantial improvement of any commercial, industrial, or other non-residential structure shall have the reference level, including basement, elevated no lower than the regulatory flood protection elevation, as defined in § 154.05 of this chapter. Structures located in A, AE, and A1-30 Zones may be floodproofed to the regulatory flood protection elevation in lieu of elevation provided that all areas of the structure, together with attendant utility and sanitary facilities, below the regulatory flood protection elevation are watertight with walls substantially impermeable to the passage of water, using structural components having the capability of resisting hydrostatic and hydrodynamic loads and the effect of buoyancy. For AO Zones, the floodproofing
elevation shall be in accordance with division (D) below. A registered professional engineer or architect shall certify that the standards of this division (B) are satisfied. Such certification shall be provided to the Floodplain Administrator as set forth in § 154.31(C), along with the operational and maintenance plans.
(C) Manufactured homes.
(1) New or replacement manufactured home shall be elevated so that the reference level of the manufactured home is no lower than the regulatory flood protection elevation, as defined in § 154.05 of this chapter.
(2) Manufactured homes shall be securely anchored to an adequately anchored foundation to resist flotation, collapse, and lateral movement, either by engineer certification, or in accordance with the most current edition of the state’s regulations for manufactured homes, adopted by the State Fire Marshal pursuant to G.S. § 143-143.15 or a certified engineered foundation. Additionally, when the elevation would be met by an elevation of the chassis 36 inches or less above the grade at the site, the chassis shall be supported by reinforced piers or engineered foundation. When the elevation of the chassis is above 36 inches in height, an engineering certification is required.
(3) All enclosures or skirting below the lowest floor shall meet the requirements of divisions (D)(1), (D)(2), and (D)(3) below.
(4) An evacuation plan must be developed for evacuation of all residents of all new, substantially improved, or substantially damaged manufactured home parks or subdivisions located within flood prone areas. This plan shall be filed with, and approved by, the Floodplain Administrator and the local Emergency Management Coordinator.
(D) Elevated buildings. Fully enclosed areas of new construction and substantially improved structures which are below the lowest floor:
(1) Shall not be designed or used for human habitation, but shall only be used for parking of vehicles, building access, or limited storage of maintenance equipment used in connection with the premises. Access to the enclosed area shall be the minimum necessary to allow for parking of vehicles (garage door) or limited storage of maintenance equipment (standard exterior door), or entry to the living area (stairway or elevator). The interior portion of such enclosed area shall not be finished or partitioned into separate rooms, except to enclose storage areas;
(2) Shall be constructed entirely of flood resistant materials, up to the regulatory flood protection elevation;
(3) Shall include, in Zones A, AO, AE, and A1-30, flood openings to automatically equalize hydrostatic flood forces on walls by allowing for the entry and exit of floodwaters. To meet this requirement, the openings must either be certified by a professional engineer or architect or meet or exceed the following minimum design criteria:
(a) A minimum of two flood openings on different sides of each enclosed area subject to flooding;
(b) The total net area of all flood openings must be at least one square inch for each square foot of enclosed area subject to flooding;
(c) If a building has more than one enclosed area, each enclosed area must have flood openings to allow floodwaters to automatically enter and exit;
(d) The bottom of all required flood openings shall be no higher than one foot above the adjacent grade;
(e) Flood openings may be equipped with screens, louvers, or other coverings or devices, provided they permit the automatic flow of floodwaters in both directions; and
(f) Enclosures made of flexible skirting are not considered enclosures for regulatory purposes, and therefore, do not require flood openings. Masonry or wood underpinning, regardless of structural status, is considered an enclosure and requires flood openings as outlined above.
(4) Shall allow, in coastal high hazard areas (Zones VE and V1-30), breakaway walls, open wood latticework, or insect screening, provided it is not part of the structural support of the building and is designed so as to breakaway, under abnormally high tides or wave action, without causing damage to the structural integrity of the building, provided the following design specification are met:
(a) Material shall consist of open wood latticework or insect screening; or
(b) Breakaway walls shall meet the following design specifications:
1. Design safe loading resistance of each wall shall be not less than ten nor more than 20 pounds per square foot; or
2. Breakaway walls that exceed a design safe loading resistance or 20 pounds per square foot (either by design or when so required by state or local codes) shall be certified by a registered professional engineer or architect that the breakaway wall will collapse from a water load less than that which would occur during the base flood event, and the elevated portion of the building and supporting foundation system shall 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 non-structural). The water loading value used shall be those associated with the base flood. The wind loading values used shall be those required by the State Building Code.
(E) Additions/improvements.
(1) Additions and/or improvements to pre-FIRM structures when the addition and/or improvements in combination with any interior modifications to the existing structure are:
(a) Not a substantial improvement, the addition and/or improvements must be designed to minimize flood damages and must not be any more non-conforming than the existing structure; or
(b) A substantial improvement, both the existing structure and the addition and/or improvements must comply with the standards for new construction.
(2) Additions to post-FIRM structures with no modifications to the existing structure other than a standard door in the common wall shall require only the addition to comply with the standards for new construction.
(3) Additions and/or improvements to post-FIRM structures when the addition and/or improvements in combination with any interior modifications to the existing structure are:
(a) Not a substantial improvement, the addition and/or improvements only must comply with the standards for new construction; or
(b) a substantial improvement, both the existing structure and the addition and/or improvements must comply with the standards for new construction.
(4) Where an independent perimeter load bearing wall is provided between the addition and the existing building, the addition(s) shall be considered a separate building and only the addition must comply with the standard for new construction.
(F) Recreational vehicles. Recreational vehicles shall either:
(1) Be on site for fewer than 180 consecutive days and be fully licensed and ready for highway use (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 has no permanently attached additions); or
(2) Meet all the requirements for new construction.
(G) Temporary non-residential structures. Prior to the issuance of a floodplain development permit for a temporary structure, the applicant must submit in writing to the Floodplain Administrator a plan for the removal of such structure(s) in the event of a hurricane, flash flood, or other type of flood warning notification. The following information shall be submitted in writing to the Floodplain Administrator for review and written approval:
(1) A specified time period for which the temporary use will be permitted. Time specified should not exceed three months, renewable up to one year;
(2) The name, address, and phone number of the individual responsible for the removal of the temporary structure;
(3) The time frame prior to the event at which a structure will be removed (i.e., minimum of 72 hours before landfall of a hurricane or immediately upon flood warning notification);
(4) A copy of the contract or other suitable instrument with the entity responsible for physical removal of the structure; and
(5) Designation, accompanied by documentation, of a location outside the special flood hazard area, to which the temporary structure will be moved.
(H) Accessory structures.
(1) When accessory structures (sheds, detached garages, and the like) are to be placed within a special flood hazard area, the following criteria shall be met.
(a) Accessory structures shall not be used for human habitation (including working, sleeping, living, cooking, or restroom areas).
(b) Accessory structures shall not be temperature-controlled.
(c) Accessory structures shall be designed to have low flood damage potential.
(d) Accessory structures shall be constructed and placed on the building site so as to offer the minimum resistance to the flow of floodwaters.
(e) Accessory structures shall be firmly anchored in accordance with § 154.45(A).
(f) All service facilities such as electrical shall be installed in accordance with § 154.45(D).
(g) Flood openings to facilitate automatic equalization of hydrostatic flood forces shall be provided below regulatory flood protection elevation in conformance with division (D)(3) above.
(2) An accessory structure with a footprint less than 150 square feet that satisfies the criteria outlined above does not require an elevation or floodproofing certificate. Elevation or floodproofing certifications are required for all other accessory structures in accordance with division (C) above.
(Ord. passed 5-25-2006) Penalty, see § 154.99