Sec. 32B-20. Standards of construction.
In all special flood hazard areas the following standards are required:
A. Anchoring.
1. All new construction and substantial improvements must be anchored to prevent flotation, collapse or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads, including the effects of buoyancy; and
2. All manufactured homes must meet the anchoring standards of Section 32B-24(A)(2).
B. Construction materials and methods.
1. All new construction and substantial improvements must be constructed with materials and utility equipment resistant to flood damage;
2. All new construction and substantial improvements must be constructed using methods and practices that minimize flood damage;
3. All new construction and substantial improvement and other proposed new development with mechanical and utility equipment utilized by the structure must be constructed to or above the regulatory flood elevation;
4. Within Zone AH or AO, adequate drainage paths must be constructed around structures on slopes to guide floodwaters around and away from proposed structures.
C. Elevation and floodproofing.
1. Residential construction. Residential construction, new or substantial improvement, must have the lowest floor, including basement, elevated to or above the regulatory flood elevation:
a. In Zone AO, the base flood elevation is determined from the FIRM panel. If unspecified, the required elevation is a minimum two feet above the highest adjacent grade.
b. In Zone A, where a BFE has not been determined, the base flood elevation is determined locally as set out in Section 32B-18(C).
c. In Zones AE and AH, the base flood elevation is determined from the FIS and/or FIRM.
d. A garage attached to a residential structure, constructed with the garage floor slab below the regulatory flood elevation, must be designed to allow for the automatic entry and exit of floodwaters and must be used solely for parking, access and/or storage. See subsection (C)(3) of this section.
Upon completion of the structure, the elevation of the lowest floor including basement must be certified by a registered professional engineer or surveyor, and verified by the community’s building inspector to be properly elevated. Such certification and verification must be provided to the Floodplain Administrator.
2. Nonresidential construction. Nonresidential construction, new or substantial improvement, must either be elevated to conform with subsection (C)(1) of this section or together with attendant utility and sanitary facilities:
a. Be floodproofed below the elevation recommended under subsection (C)(1) of this section so that the structure is watertight with walls substantially impermeable to the passage of water; and
b. Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy.
c. Upon completion of the structure, certification by a registered professional engineer or surveyor that the elevation requirements of the lowest floor, including basement, of this section have been satisfied shall be provided to the Floodplain Administrator; or certification by a registered professional engineer or architect that the floodproofing standards of this section are satisfied shall be provided to the Floodplain Administrator for verification.
3. Flood openings. All new construction and substantial improvement with fully enclosed areas below the lowest floor (excluding basements) that are usable solely for parking of vehicles, building access or storage, and which are subject to flooding, must be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwater. Designs for meeting this requirement must meet or exceed the following criteria:
a. For nonengineered openings:
(1) Have a minimum of two openings, on different sides of each enclosed area, 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 must be no higher than one foot above grade.
(3) Openings may be equipped with screens, louvers, valves, or other coverings or devices; provided, that they permit the automatic entry and exit of floodwater; or
b. For engineered openings (or covers and devices):
(1) Are specifically designed and certified by a registered engineer or architect as meeting the required performance and design requirements.
(2) Have an evaluation report issued by the International Code Council Evaluation Service (ICC-ES), Inc., a subsidiary of the International Code Council, Inc.
4. Manufactured homes. Manufactured homes must meet the standards in Section 32B-24.
5. Accessory structures.
a. An "accessory structure" used solely for parking or storage, as defined in Article II of this chapter, may be constructed such that its floor is below the regulatory flood elevation, provided the structure is designed and constructed in accordance with the following requirements:
(1) Use of the accessory structure must be limited to parking or storage;
(2) The portions of the accessory structure located below the regulatory flood elevation must be built using flood-resistant materials;
(3) The accessory structure must be adequately anchored to prevent flotation, collapse and lateral movement;
(4) Any mechanical and utility equipment in the accessory structure must be elevated or floodproofed to or above the regulatory flood elevation;
(5) The accessory structure must comply with floodway encroachment provisions in Section 32B-26; and
(6) The accessory structure must be designed to allow for the automatic entry of flood waters in accordance with subsection (C)(3) of this section.
Accessory structures not meeting the above standards must be constructed in accordance with all applicable standards in this section.
Upon completion of an accessory structure, certification by a registered professional engineer, surveyor or local official that the requirements of this section have been satisfied must be provided to the Floodplain Administrator for verification.
6. Machinery and service equipment. All new construction, substantial improvement and other proposed new development must be constructed with electrical, heating, ventilation, plumbing, and air conditioning equipment and other service facilities that are designed and/or located so as to prevent water from entering or accumulating within the components during conditions of flooding. (Ord. No. G-5707, 2012; Ord. No. G-6611, 2019; Ord. No. G-7116, § 2, 2023; Ord. No. G-7218, § 2, 2024)