New construction or substantial improvements of elevated and crawl space buildings that include fully-enclosed areas formed by foundation and other walls below the design flood elevation shall be designed to preclude finished living space, and to allow for the entry and exit of floodwaters to automatically equalize hydrostatic flood forces on the walls.
(A) Designs for complying with this requirement must either be certified by a professional engineer or architect, or meet the following minimum criteria:
(1) Provide a minimum of two openings, located on two different walls of the enclosure, having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding;
(2) The bottom of all openings shall be no higher than one foot above grade; and
(3) Openings may be equipped with screens, louvers, valves, or other coverings or devices, provided they permit the automatic flow of floodwaters in both directions.
(B) For elevated buildings, enclosed areas below the design flood elevation shall not exceed 299 square feet cumulatively. The enclosed areas cannot be temperature controlled.
(C) Elevated building shall be supported by piers, piles or other open foundation systems. Non- load-bearing panels may be installed around the perimeter of the foundation area between the structural supports. These panels shall not be considered enclosure walls for the purposes of division (B) above, provided they meet the following conditions:
(1) Each panel section installed between structural supports shall be constructed with permanent openings, and the net area of these openings shall not be less than 40% of the total area of the opening in which the panel is installed;
(2) Each panel section must have openings within one foot of grade to allow for the entry and exit of floodwaters as per division (A) above;
(3) The area within the foundation perimeter shall not be divided or partitioned in any manner, except as allowed in division (B) above; and
(4) Access to the enclosed area(s) allowed in division (B) above shall be the minimum necessary to allow for parking of vehicles (garage door), or limited storage (standard exterior door), or entry to the living area (stairway or elevator).
(D) A nonconversion agreement, as supplied by the Town Building Inspection Division, is required to be executed for all new and substantially improved elevated buildings where the ground floor is below the design flood elevation. The nonconversion agreement shall be registered with the Charleston County Register of Deeds (ROD) Office, and a recorded copy must be returned to the Building Inspection Division Office prior to the issuance of a certificate of occupancy.
(‘81 Code, § 152.05 b.) (Ord. passed 3-5-84; Am. Ord. passed 6-11-91; Am. Ord. passed 12-17-91; Am. Ord. passed 5-19-92; Am. Ord. 07055, passed 9-11-07; Am. Ord. 18039, passed 6-14-18; Am. Ord. 20065, passed 11-10-20)