In all areas within the city limits of Folly Beach, all permits for new construction and substantial improvement must be reviewed to determine whether proposed structures will be reasonably safe from flooding. Permits will be reviewed to ensure that all necessary permits have been received from those governmental agencies from which approval is required by federal or state law, including section 404 of the Federal Water Pollution Control Act Amendments of 1972, 33 U.S.C. 1334 and that no adverse impact occurs during the development process as authorized by 44 CFR 59 and 60. Additionally, the following provisions are required:
(A) New construction and substantial improve- ments shall be anchored to prevent flotation, collapse or lateral movement of the structure.
(B) (1) Manufactured homes shall be anchored to prevent flotation, collapse or lateral movement.
(2) Methods of anchoring may include, but are not limited to use of over-the-top or frame ties to ground anchors.
(3) This standard shall be in addition to and consistent with applicable state requirements for resisting wind forces.
(C) New construction and substantial improvements shall be constructed with materials and utility equipment resistant to flood damage.
(D) New construction or substantial improve- ments shall be constructed by methods and practices that minimize flood damage.
(E) Electrical, heating, ventilation, plumbing, air conditioning equipment and other service facilities shall be designed and/or located so as to prevent water from entering or accumulating within the components during conditions of flooding to the design flood elevation (DFE).
(F) New and replacement water supply systems shall be designed to minimize or eliminate infiltration of flood waters into the system.
(G) New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of flood waters into the systems and discharges from the systems into flood waters.
(H) On-site waste disposal systems shall be located and constructed to avoid impairment to them or contamination from them during flooding.
(I) Any alteration, repair, reconstruction or improvements to a structure which is in compliance with the provisions of this chapter, shall meet the requirements of “new construction,” as contained in this chapter.
(J) Noncompliant buildings or uses may not be enlarged, replaced, or rebuilt unless such enlargement or reconstruction is accomplished in conformance with the provisions of this chapter. Provided, however, nothing in this chapter shall prevent the repair, of an existing building or structure located totally or partially within the floodway, provided that the bulk of the building or structure below base flood elevation in the floodway is not increased and provided that such repair meets all of the other requirements of this chapter.
(K) All new and substantially improved critical development shall be elevated to the 500-year flood elevation or be elevated to the highest known historical flood elevation (where records are available), whichever is greater. If no data exists establishing the 500-year flood elevation or the highest known historical flood elevation, the applicant shall provide a hydrologic and hydraulic engineering analysis that generates 500-year flood elevation data.
(L) All gas or liquid storage tanks, either located above ground or buried, shall be anchored to prevent floatation and lateral movement resulting from hydrodynamic and hydrostatic loads.
(M) All new construction and substantial improvements must meet the Americans with Disabilities Act (ADA) requirements including specific ADA requirements for construction in the floodplain. The ADA shall not be used as justification for the issuance of a variance or otherwise waiving floodplain construction requirements. The cost of applicable ADA improvements shall be included in calculating the threshold of substantial improvement.
(N) Elevated buildings.
(1) New construction and substantial improvements of elevated buildings that include fully enclosed areas formed by foundation and other exterior walls below the design flood elevation shall be designed to preclude finished living space and designed to allow for the entry and exit of floodwaters to automatically equalize hydrostatic flood forces on exterior walls.
(2) Designs for complying with this requirement must either be certified by a professional engineer or architect or meet the following minimum criteria:
(a) Provide a minimum of two openings having a total net area of not less than one square inch for every square foot of enclosed area below the design flood elevation;
(b) The bottom of all openings shall be no higher than one foot above the higher of the interior or exterior grade immediately under the opening;
(c) Openings may be equipped with screens, louvers, valves or other coverings or devices provided they permit the automatic flow of floodwaters in both directions;
(d) Only the portions of openings that are below the design flood elevation (DFE) can be counted towards the required net open area, and;
(e) Fill placed around foundation walls must be graded so that the grade inside the enclosed area is equal to or higher than the adjacent grade outside the building on at least one side of the building.
(3) Electrical, plumbing, and other utility connections are prohibited below the design flood elevation except that one wet location switch and/or outlet connected to a ground fault interrupt breaker may be installed below the required lowest floor elevation.
(4) 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).
(5) The interior portion of the enclosed area shall not be partitioned or finished into separate rooms.
(6) Prior to receiving a permit to construct or renovate a structure in the flood plain, the owner must sign and file with the Charleston County Register of Mesne Conveyance a non-conversion agreement, which promises not to improve, finish, or otherwise convert the area below the area below DFE and grants community officials the right to inspect the enclosed area. The non-conversion agreement shall be of a form determined by the Building Official.
(7) Hydrodynamic pressure must be considered in the design of any foundation system where velocity waters or the potential for debris flow exists. If flood velocities are excessive (greater than five feet per second), foundation systems other than solid foundations walls should be considered so that obstructions to damaging flood flows are minimized.
(8) All construction materials below the required lowest floor elevation shall be of flood resistant materials.
(9) All new construction and substantial improvements shall be located landward of the OCRM Baseline as well as comply with all applicable Department of Health and Environmental Control (DHEC) Ocean and Coastal Resource Management (OCRM) setback requirements.
(10) All buildings shall be elevated so that the bottom of the lowest supporting horizontal member (excluding pilings or columns) and any associated utilities are located no lower than the design flood elevation.
(a) Open lattice work or decorative screening may be permitted for aesthetic purposes only and must be designed to wash away in the event of abnormal wave action and in accordance with division (F)(8) above.
(b) Breakaway (solid) walls may be permitted, provided that they are designed to break away from columns or pilings at a maximum horizontal pressure of 20 pounds per square foot applied to the projected area, leaving columns or pilings intact, but shall not break away at less than a horizontal pressure of 15 pounds per square foot on the projected area.
1. Breakaway construction design shall be certified by a registered South Carolina architect or engineer and a certificate verifying the same shall be submitted upon completion of construction. Final inspection approval shall be withheld until this certification is received.
2. No plumbing pipes, gas pipes, electrical wires or other equipment shall be run or mounted on or in the breakaway wall or in any way impede or prevent the wall from breaking away under the designated load.
3. Solid breakaway walls shall be allowed only for added security for the storage of a homeowner's personal belongings and shall not in any way be incorporated as living space or designed as part of the structure used for human habitation and must be vented per division (N). The Building Official shall at all times be allowed right of entry for inspection purposes to ascertain that the area behind the breakaway walls are used for no other purpose other than storage.
4. Secondary breakaway wall enclosures shall not exceed 299 square feet.
5. Only flood resistant materials shall be used below the required flood elevation. One wet location switch and/or outlet connected to a ground fault interrupt breaker may be installed below the required lowest floor elevation.
(11) All buildings or structures shall be securely anchored on pilings or columns.
(12) All piles and columns and the structures attached thereto shall be anchored to resist flotation, collapse and lateral movement due to the effect of wind and water loads acting simultaneously on all building components. Water loading values shall equal or exceed the base flood. Wind loading values shall be in accordance with Standard Building Code, current edition.
(13) A registered professional engineer or architect shall certify that the design, specifications and plans for construction are in compliance with the provisions contained in this section.
(14) 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, which demonstrates that the following factors have been fully considered:
(a) Particle composition of fill material does not have a tendency for excessive natural compaction;
(b) Volume and distribution of fill will not cause wave deflection to adjacent properties; and
(c) Slope of fill will not cause wave run-up or ramping.
(15) There shall be no alteration of sand dunes which would increase potential flood damage.
(16) Lattice work or decorative screening shall be allowed below the design flood elevation provided it is not part of the structural support of the building and is designed to break away under abnormally high tides or wave action without damage to the structural integrity of the building on which it is to be used and further provided that at least 60% of the area is void and evenly distributed throughout and located between piles or columns and meets all other requirements under this section.
(17) If aesthetic lattice work or screening (breakaway walls) are utilized, the enclosed space shall not be designed to be useable for human habitation but shall be designed to be useable only for parking of vehicles, building access or limited storage of maintenance equipment used in connection with the premises.
(18) Prior to construction, plans for any structures that will have breakaway walls must be submitted to the Building Official for approval.
(19) Any alteration, repair, reconstruction or improvement to a structure shall not enclose the space below the lowest floor except with lattice work or decorative screening, as provided for in divisions (F)(8) and (F)(9) above.
(20) Prohibit the placement of manufactured homes (mobile homes), except in an existing manufactured homes (mobile homes) park or subdivision. A replacement manufactured home may be placed on a lot in an existing manufactured home park or subdivision provided the anchoring standards of division (B) and the elevation standards of division (A) above are met.
(21) Accessory structures, below the required lowest floor elevation are prohibited in V-zones except for the following:
(a) Swimming pools which:
1. Must be installed at-grade or elevated so long as the pool will not act as an obstruction.
2. Must be structurally independent of the building and its foundation.
3. May be placed beneath a coastal building only if the top of the pool and any accompanying decking or walkway are flush with the existing grade and only if the lower area remains unenclosed.
4. Must be part of the certification process for V-zone buildings by which a design professional must consider the effects that any of these elements will have on the building in question and any nearby buildings.
(b) Access stairs attached to or beneath an elevated building which:
1. Must be constructed of flood-resistant materials.
2. Must be constructed as open staircases so they do not block flow under the structure.
(c) Decks as follows:
1. If the deck is structurally attached to a building then the bottom of the lowest horizontal member must be at or above the elevation of the building's lowest horizontal member.
2. If the deck is to be built below the DFE then it must be structurally independent of the main building and must not cause an obstruction.
3. If an at-grade, structurally independent deck is proposed then a design professional must evaluate the design to determine if it will adversely affect the building and nearby buildings.
(22) Parking areas should be located on a stable grade under or landward of a structure. Any parking surface shall consist of gravel or aggregate.
(23) Electrical, ventilation, plumbing, heating and air conditioning equipment (including ductwork), and other service facilities shall be designed and/or located so as to prevent water from entering or accumulating within the components during conditions of the design flood elevation. This requirement does not exclude the installation of outdoor faucets for shower heads, sinks, hoses, etc., as long as cut off devices and back flow prevention devices are installed to prevent contamination to the service components and thereby minimize any flood damages to the building. No utilities or components shall be attached to breakaway walls.
(`95 Code, § 5-4-18) (Am. Ord. 05-97, passed 4-1-97; Am. Ord. 24-99, passed 9-14-99; Am. Ord. 01-00, passed 2-22-00; Am. Ord. 22-16, passed 9-13-16; Am. Ord. 21-17, passed 7-11-17; Am. Ord. 08-19, passed 2-11-19; Am. Ord. 04-21, passed 1-22-21; Am. Ord. 10-21, passed 5-11-21)