(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 § 154.03.
(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 § 154.03. 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 this chapter. A registered professional engineer or architect shall certify that the standards of this division are satisfied. Such certification shall be provided to the Floodplain Administrator as set forth in § 154.36(C), along with the operational and maintenance plans.
(C) Manufactured homes.
(1) New or replacement manufactured homes shall be elevated so that the reference level of the manufactured home is no lower than the regulatory flood protection elevation, as defined in § 154.03.
(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 of North Carolina Regulations for Manufactured Homes, adopted by the Commissioner of Insurance 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 division (D) of this section.
(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;
Exception: Elevators and accessible interior stairs may be finished if approved flood proof materials are used below the RFPE.
Exception: elevators and accessible interior stairs may be finished if approved floodproof materials are used below the RFPE.
(2) Shall be constructed entirely of flood resistant materials, up to the regulatory flood protection elevation;
(3) Shall include, in Zone AE, 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 (Zone VE), 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 specifications 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 of 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 values used shall be those associated with the base flood. The wind loading values used shall be those required by the North Carolina 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.
(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; and
(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 standards for new construction.
(5) Any combination of repair, reconstruction, rehabilitation, addition or improvement of a building or structure taking place during a two year period, the cumulative cost of which equals or exceeds 50% of the market value of the structure before the improvement or repair is started must comply with the standards for new construction. For each building or structure, the two year period begins on the date of the first improvement or repair of that building or structure subsequent to the effective date of this chapter. Substantial damage also means flood-related damage sustained by a structure on two separate occasions during a ten- year period for which the cost of repairs at the time of each such flood event, on the average, equals or exceeds 25% of the market value of the structure before the damage occurred. If the structure has sustained substantial damage, any repairs are considered substantial improvement regardless of the actual repair work performed. The requirement does not, however, include either:
(a) Any project for improvement of a building required to correct existing health, sanitary or safety code violations identified by the building official and that are the minimum necessary to assume safe living conditions; or
(b) Any alteration of a historic structure provided that the alteration will not preclude the structure’s continued designation as a historic structure.
(F) Recreational vehicles. Recreational vehicles shall either:
(1) Temporary placement. 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) Permanent placement. Recreational vehicles that do not meet the limitations of temporary placement shall 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 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, etc.) 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 § 154.20;
(f) All service facilities such as electrical shall be installed in accordance with § 154.20; and
(g) Flood openings to facilitate automatic equalization of hydrostatic flood forces shall be provided below regulatory flood protection elevation in conformance with division (D) of this section.
(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 § 154.36(C).
(3) Tanks. When gas and liquid storage tanks are to be placed within a special flood hazard area, the following criteria shall be met:
(a) Underground tanks. Underground tanks in flood hazard areas shall be anchored to prevent flotation, collapse or lateral movement resulting from hydrodynamic and hydrostatic loads during conditions of the design flood, including the effects of buoyancy assuming the tank is empty;
(b) Above-ground tanks, elevated. Above ground tanks in flood hazard areas shall be elevated to or above the regular flood protection elevation on a supporting structure that is designed to prevent flotation, collapse or lateral movement during conditions of the design flood. Tank-supporting structures shall meet the foundation requirements of the applicable flood hazard area;
(c) Above ground tanks, not elevated. Above-ground tanks that do not meet the elevation requirements of § 154.23 shall be permitted in flood hazard areas provided the tanks are designed, constructed, installed, and anchored to resist all flood- related and other loads, including the effects of buoyancy, during conditions of the design flood and without release of contents in the floodwaters or infiltration by floodwaters into the tanks. Tanks shall be designed, constructed, installed, and anchored to resist the potential buoyant and other flood forces acting on an empty tank during design flood conditions.
(d) Tank inlets and vents. Tank inlets, fill openings, outlets and vents shall be:
1. At or above the regulatory flood protection elevation or fitted with covers designed to prevent the inflow of floodwater or outflow of the contents of the tanks during conditions of the design flood; and
2. Anchored to prevent lateral movement resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy, during conditions of the design flood.
(4) Other development.
(a) Fences in regulated floodways and NEAs that have the potential to block the passage of floodwaters, such as stockade fences and wire mesh fences, shall meet the limitations of § 154.23.
(b) Retaining walls, sidewalks and driveways in regulated floodways and NEAs. Retaining walls and sidewalks and driveways that involve the placement of fill in regulated floodways shall meet the limitations of § 154.23.
(c) Roads and watercourse crossings in regulated floodways and NEAs. Roads and watercourse crossings, including roads, bridges, culverts, low- water crossings and similar means for vehicles or pedestrians to travel from one side of a watercourse to the other side, that encroach into regulated floodways shall meet the limitations of § 154.23.
(‘85 Code, § 8-4.5b.) (Ord. 31, passed - - ; Am. Ord. 5-87, passed 3-24-87; Am. Ord. 03-01, passed 2-24-03; Am. Ord. 06-06, passed 5-22-06; Am. Ord. 18-13, passed 8-6-18; Am. Ord. 20-11, passed 9-3-20; Am. Ord. 21-10, passed 6-15-21) Penalty, see § 154.99