Specific standards.
Charleston, S.C., City Code § 27-117
in effectSec. 27-117. - Specific standards.
In all areas of special flood hazard where base flood elevation data has been provided, as set forth in section 27-105 or section 27-113(9), the following provisions are required:
(1) Residential construction. New construction shall have the lowest floor, including basement, or the applicable structural member elevated at least two (2) feet above the level of base flood elevation prescribed for that zone. Substantial improvement of any residential structure shall have the lowest floor, including basement, or the applicable structural member elevated at least one (1) foot above the level of the base flood elevation prescribed for that zone.
(2) Non-residential construction. New construction or substantial improvement of any commercial, industrial or other non-residential structure on or after April 9, 1971 shall either have the lowest floor, including basement, or the applicable structural member elevated at least two (2) feet above the level of the base flood elevation prescribed for that zone or, together with attendant utility and sanitary facilities be flood-proofed in accordance with the FEMA publication "Floodproofing Non-Residential Structures" (2013), so that all areas below the required elevation are watertight and with walls substantially impermeable to the passage of water and with structural components having the capability of resisting hydrostatic and hydrodynamic loads and effects of buoyancy. A registered professional engineer or architect shall certify that the standards of this subparagraph (2) are satisfied. Such certification shall be provided to the city as set forth in section 27-114(3) of this division.
(3) Elevated buildings. New construction or substantial improvements of elevated buildings that include fully enclosed areas formed by foundation and other exterior walls below the base flood elevation shall be designed to preclude finished living space and designed to allow for the entry and exit of flood waters to automatically equalize hydrostatic flood forces on exterior walls.
a. Designs for complying with this requirement must either be certified by a professional engineer or architect or meet the following minimum criteria:
i. Provide a minimum of two (2) openings having a total net area of not less than one (1) square inch for every square foot of enclosed area subject to flooding;
ii. The bottom of all openings shall be no higher than one (1) foot above grade; and
iii. Openings may be equipped with screens, louvers, valves or other coverings or devices provided they permit the automatic flow of floodwater in both directions.
b. Access to the enclosed area shall be the minimum necessary to allow for parking of vehicles (garage door) or limited storage of maintenance equipment used in connection with the premises (standard exterior door) or entry to the living area (stairway or elevator); and
c. The interior portion of such enclosed area shall not be partitioned or finished into separate rooms.
(4) Manufactured homes. Manufactured homes are subject to the following:
a. No manufactured home shall be placed in a floodway or coastal high hazard area, except in an existing manufactured park or existing manufactured home subdivision. Manufactured homes placed in existing manufactured home subdivision in floodway or coastal high hazard areas shall be anchored as specified in subsection 27-117(4)b. and meet the elevation requirements in subsection 27-117(4)d.(i).
b. All manufactured homes shall be anchored to resist floatation, collapse, or lateral movement by providing over-the-top and frame ties to ground anchors. Specific requirements shall be that:
i. Over-the-top ties shall be provided at each end of the manufactured home, with one (1) additional tie per side at an intermediate location on manufactured homes of less fifty (50) feet and one (1) additional tie per side for manufactured homes of fifty (50) feet or more;
ii. Frame ties shall be provided at each corner of the home with four (4) additional ties per side at intermediate points for manufactured home less than fifty (50) feet long and one (1) additional tie for manufactured homes of fifty (50) feet or longer;
iii. All components of the anchoring system shall be capable of carrying a force of four thousand eight hundred (4,800) pounds; and
iv. Any additions to the manufactured home shall be similarly anchored.
c. For new manufactured home parks and subdivisions; for expansions to existing manufactured home parks and subdivisions; for existing parks and subdivisions where the repair, reconstruction or improvement of the streets, utilities and pads equal or exceed fifty (50) percent of value of the streets, utilities and pads before the repair, reconstruction or improvement has commenced; and, for manufactured homes not placed in a manufactured park or subdivision it is required that:
i. Stands or lots be elevated on compacted fill or on pilings so that the lowest floor of new construction of the manufactured home will be at least two (2) feet above the base flood level;
ii. Adequate surface drainage and access for a hauler be provided; and
iii. In the instance of elevation on pilings:
(i) Lots be large enough to permit steps;
(ii) Piling foundations be placed in stable soil no more than ten (10) feet apart; and
(iii) Reinforcement be provided for pilings more than six (6) feet above the ground level.
d. All manufactured homes placed or substantially improved in an existing manufactured home park or subdivision must be elevated so that:
i. The lowest floor of new construction of the manufactured home is elevated to at least two (2) feet above the level of the base flood elevation;
ii. The manufactured home must be securely anchored to the adequately anchored foundation system to resist floatation, collapse and lateral movement.
iii. In an existing manufactured home park or subdivision on which a manufactured home has incurred "substantial damage" as the result of a flood, any manufactured home placed or substantially improved must meet the standards of subsection 27-117(4)d.(i) and (ii) above.
(5) Floodways. Located within the areas of special flood hazard established in section 27-105 are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of flood waters which carry debris, potential projectiles, and has erosion potential, the following provisions shall apply:
a. No encroachments, including fill, or new construction or substantial improvements or any other developments shall be had until and unless certification (with supporting technical data) by a registered professional engineer is provided to the city engineer or his designated agent demonstrating that such activity shall not result in any increase in flood levels during occurrence of the base flood discharge;
b. In the event the provisions of subparagraph (4)a. of this section are satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of this division (Division 3).
c. There shall be no placement of any manufactured homes, except in an existing manufactured park or existing manufactured home subdivision.
(6) High hazard areas—V or VE zones. Specific standards high hazard areas V or VE zones located within the areas of special flood hazard are areas designated as coastal high hazard areas. These areas have special flood hazards associated with wave wash, and therefore, the following provisions shall apply:
a. All new construction within zones V and VE on the Charleston FIRM shall be located landward of the reach of mean high tide.
b. Provide that all new construction and substantial improvements in zones V and VE, if base flood elevation data is available on the Charleston FIRM, are elevated on pilings and columns so that:
i. The bottom of the lowest horizontal structural member of the lowest floor (excluding the pilings or columns) of new construction is elevated to or above two (2) feet above the base flood level; and
ii. The pile or column foundation and structure attached thereto is anchored to resist flotation, collapse and lateral movement due to the effects of wind and water loads acting simultaneously on all building components. Water loading values used shall be those associated with the base flood. Wind loading values used shall be those required by the International Building Code or International Residential Code as adopted and periodically amended by the South Carolina Department of Labor, Licensing and Regulation. A registered professional engineer or architect licensed in South Carolina shall develop the structural design, specifications and plans for construction, and shall certify that the design and methods of construction to be used are in accordance with accepted standards of practice for meeting the provisions of subsections (6)b.i. and ii. of section 27-117 of the Code of Ordinances, of the City of Charleston, South Carolina.
c. New construction and substantial improvements within zones V and VE on the Charleston FIRM have the space below the lowest floor either free of obstruction or constructed with non-supporting breakaway walls, open wood latticework, 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. For the purposes of this section, a breakaway wall shall have a design safe loading resistance of not less than ten and no more than twenty (20) pounds per square foot. Use of breakaway walls which exceed a design safe loading resistance of twenty (20) pounds per square foot (either by design or when so required by local or state codes) may be permitted only if a registered professional engineer or architect licensed in South Carolina certifies that the designs proposed meet the following conditions:
i. Breakaway wall collapse shall result from a water load less than that which would occur during the base flood; and
ii. The elevated portion of the building and supporting foundations 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 nonstructural). Water loading values used shall be those associated with the base flood. Wind loading values used shall be those required by applicable state or local building standards. Such enclosed space shall be useable solely for parking of vehicles, building access, or storage.
d. There shall be no fill used as structural support. Non-compacted fill may be used around the perimeter of a building for landscaping/aesthetic purposes provided the fill will wash out from storm surge, thereby rendering the building free of obstruction prior to generating excessive loading forces, ramping effects, or wave deflection. The building official shall approve design plans for landscaping/aesthetic fill only after the applicant has provided an analysis by an engineer, architect, and/or soil scientist licensed in South Carolina which demonstrates that the following factors have been fully considered:
i. Particle composition of fill material does not have a tendency for excessive natural compaction;
ii. Volume and distribution of fill will not cause wave deflection to adjacent properties; and
iii. Slope of fill will not cause wave run-up or ramping.
e. Manmade alteration of sand dunes and mangrove stands within zones VE and V on the Charleston FIRM which would increase potential flood damage shall be prohibited.
f. The placement of new or replacement manufactured homes is prohibited.
g. A modular building (manufactured) may be installed in a V or VE zone, providing the requirements in this subsection are met, and the building meets the standards of the South Carolina Modular Building Construction Act (S.C. Code 1976, § 23-43-10 et seq.) as may be amended from time to time, which is incorporated herein by reference.
h. Preconstruction and as-built design and breakaway wall certifications, where applicable, shall be provided by registered professional engineers and/or architects licensed in South Carolina for new and substantially improved structures in V or VE flood zones on the Charleston FIRM. These certificates shall also be provided for all lateral additions to structures in V or VE flood zones.
i. Enclosed areas below the lowest floor shall be the minimum necessary to allow for parking of vehicles, limited storage, and access to the primary occupancy (stairways and/or elevator).
j. Appurtenant features, defined as swimming pools, decks, gazebos, fences, and other features as determined by the building official as potentially causing an obstruction in the coastal high hazard area, must comply with the Federal Emergency Management Agency (FEMA) Technical Bulletin 5-93, Free of Obstruction Requirements, or any revisions thereto, incorporated herein by reference.
(7) Recreational vehicles. All recreational vehicles placed on sites must either:
a. Be fully licensed and ready for highway use; or
b. The recreational vehicle must meet all the requirements for new construction, including anchoring and elevation requirements of subsection 27-117(4), Manufactured homes. 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 structures.
(Ord. No. 2008-58, § 2, 4-8-08; Ord. No. 2014-123, §§ 5, 6, 9-9-14; Ord. No. 2020-032, §§ 1—5, 3-10-20; Ord. No. 2021-008, § 1, 1-26-21)
Source: City of Charleston, South Carolina, Code of Ordinances and Zoning Ordinance (Municode Library, library.municode.com)URL: https://library.municode.com/sc/charleston/codes/code_of_ordinances?nodeId=CICO_CH27STMAFLCO_ARTIISTFAFLHADAPRCO_DIV3FLHAPRCO_S27-117SPSTFetched: 11/7/2026