(A) Residential construction. New construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated to, or above, the base flood elevation. A registered professional engineer, architect, or land surveyor shall submit a certification to the Floodplain Administrator that the standard of this division (A), as proposed in § 153.42, is satisfied.
(B) Nonresidential construction. New construction and substantial improvements of any commercial, industrial, or other nonresidential structure shall either have the lowest floor, including basement, elevated to, or above, the base flood level or, together with attendant utility and sanitary facilities, be designed so that below the base flood level the structure is watertight 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 develop and/or review structural design, specifications, and plans for the construction, and shall certify that the design and methods of construction are in accordance with accepted standards of practice as outlined in this division (B). A record of such certification, which includes the specific elevation in relation to mean sea level to which such structures are flood proofed, shall be maintained by the Floodplain Administrator.
(C) Enclosures. New construction and substantial improvements with fully enclosed areas below the lowest floor that are subject to flooding shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters. Designs for meeting this requirement must either be certified by a registered professional engineer or architect, or meet or exceed the following minimum criteria:
(1) A minimum of two openings having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding shall be provided;
(2) The bottom of all openings shall be no higher the two foot above grade; and
(3) Openings may be equipped with screen, louvers, valves, or other coverings or devices, provided that they permit the automatic entry and exit of floodwaters.
(D) Manufactured homes.
(1) Requires that all manufactured homes to be placed within Zone A shall be installed using methods and practices, which minimize flood damage. For the purpose of this requirement, manufactured homes must be elevated and anchored to resist flotation, collapse, or lateral movement. Methods of anchoring may include, but are not limited to, use of over-the-top or frame ties to ground anchors. This requirement is in addition to applicable state and local anchoring requirements for resisting wind forces. Specific anchoring requirements shall be:
(a) Over-the-top ties at each of the four corners of the mobile home, with two additional ties per side at intermediate locations, and mobile homes less than 50 feet long requiring one additional tie per side;
(b) Frame ties at each corner of the home, with five additional ties per side at intermediate points, and mobile homes less than 50 feet long requiring four additional ties per side;
(c) All components of the anchoring system shall be capable of carrying a force of 4,800 pounds; and
(d) Any additions to the mobile home be similarly anchored.
(2) All manufactured homes shall be in compliance with this chapter.
(3) Require that all manufactured homes to be placed or substantially improved within Zones A1-30, AH, and AE on the community’s FIRM be elevated on a permanent foundation such that the lowest floor of the manufactured home is two or more feet above the base flood elevation, and be securely anchored to an adequately anchored foundation system in accordance with the provisions of this chapter.
(4) For new mobile home parks and subdivisions, for expansions to existing mobile home parks and subdivisions, for existing mobile home parks and subdivisions where the repair, reconstruction, or improvement of the streets, utilities, and pads equals or exceed 50% of the value of the streets, utilities and pad before the repair, reconstruction, or improvement has commenced, and for mobile homes not placed in a mobile home park or subdivision require:
(a) Stands or lots are elevated on compacted fill or on pilings so that the lowest floor of the mobile home will be at or above the base flood level. A registered professional engineer, architect, or land surveyor shall submit a certification to the Building Official that the standard of this division (D) complies;
(b) Adequate surface drainage and access for a hauler are provided; and
(c) In the instance of elevation on pilings:
1. Lots are large enough to permit steps:
2. Piling foundations are placed in stable soil no more than ten feet apart; and
3. Reinforcement is provided for pilings more than six feet above the ground.
(E) Floodways. Floodways located within areas of special flood hazard established in this chapter are areas designated as floodways. Since the floodway is an extremely hazardous area due to the velocity of floodwaters which carry debris, potential projectiles, and erosion potential, the following provisions shall apply:
(1) Encroachments are prohibited, including fill, new construction, substantial improvements, and other developments unless certification by a registered professional engineer or architect is provided demonstrating that encroachments shall not result in any increase in flood levels during the occurrence of the base flood discharge; and
(2) If division (E)(1) above is satisfied, all new construction and substantial improvements shall comply with all applicable flood hazard reduction provisions of the chapter.
(Prior Code, § 17-502)
Statutory reference:
NFIP Regulations, see 44 CFR § 60.3(b)(2)
NFIP Regulations, see 44 CFR §§ 60.3(b)(4) and 60.3(b)(8)