In all areas of special flood hazards where base flood elevation data has been provided as set forth in section 12-1-5 or subsection 12-1-6-2B of this chapter, additional standards were clarified in FEMA technical bulletin 11-01 to allow crawl space construction for buildings located in the special flood hazard areas; however, adopting this provision can result in a twenty percent (20%) increase in flood insurance premiums. The following provisions are required: (Ord. 3-2009, 5-11-2009)
A. Residential Construction:
1. New construction and substantial improvement of any residential structure shall have the lowest floor, including basement, elevated one foot (1') or more above flood protection elevation. (Ord. 4-2009, 6-8-2009)
2. Fully enclosed areas below the lowest floor that are subject to flooding are prohibited, or 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 must meet or exceed the following minimum criteria:
a. A minimum of two (2) 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.
b. The bottom of all openings shall be no higher than one foot (1') above grade.
c. Openings may be equipped with screens, louvers, or other coverings or devices; provided, that they permit the automatic entry and exit of floodwaters.
Foundation vent standards required by the IBC/IRC outside the floodplain do not meet this standard and are often inadvertently permitted. Insurance rates reflect an "all or nothing" standard, meaning, partially ventilated crawl spaces may be subject to an additional loading fee of twenty (20) to twenty five percent (25%) attached to the annual insurance premium. A subgrade crawl space will be subject to an additional loading fee of twenty percent (20%) attached to the annual insurance premium.
d. Below grade crawl spaces are prohibited at sites where the velocity of floodwaters exceeds five feet (5') per second.
e. All building utility systems within the crawl space shall be elevated above base flood elevation or be designed so that floodwaters cannot enter or accumulate within the system component during flood.
f. The interior of a crawl space below the base flood elevation must not be more than two feet (2') below the lowest adjacent exterior grade (LAG) and the height of the below grade crawl space, measured from the interior grade of the crawl space to the top of the crawl space foundation must not exceed four feet (4') at any point.
g. Below grade crawl spaces constructed in accordance with the requirements listed in this subsection shall not be considered basements. However, applicants who construct buildings that have below grade crawl spaces are hereby advised that such buildings will have higher flood insurance premiums than buildings that have crawl spaces with interior elevations at or above the lowest adjacent grade. (Ord. 3-2009, 5-11-2009)
B. Nonresidential Construction: Construction and substantial improvement of any commercial, industrial or other nonresidential structure shall either have the lowest floor, including basement, elevated to the level of the flood protection elevation; or, together with attendant utility and sanitary facilities, shall: (Ord. 4-2009, 6-8-2009)
1. Be floodproofed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water;
2. Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy;
3. Be certified by a registered professional engineer or architect that the design and methods of construction are in accordance with accepted standards of practice for meeting provisions of this subsection based on their development and/or review of the structural design, specifications and plans. Such certifications shall be provided to the official as set forth in subsection 12-1-6-2B3b of this chapter;
4. Nonresidential structures that are elevated, not floodproofed, must meet the same standards for space below the lowest floor as described in subsection A2 of this section;
5. Applicants floodproofing nonresidential buildings shall be notified that flood insurance premiums will be based on rates that are one foot (1') below the floodproofed level (e.g., a building constructed to the base flood level will be rated as one foot below that level). (Ord. 15-86, 2-9-1987)
C. Manufactured Homes: All manufactured homes to be placed or substantially improved within zones A1-30, AH, and AE shall be elevated on a permanent foundation such that the lowest floor of the manufactured home is at or above the flood protection elevation and be securely anchored to an adequately anchored foundation system in accordance with the provisions of subsection 12-1-7-1A of this chapter.
D. Recreational Vehicles: Recreational vehicles placed on sites are required to either:
1. Be on the site for fewer than one hundred eighty (180) consecutive days, or
2. Be fully licensed and ready for highway use, on wheels or jacking system, attached to the site only by quick disconnect type utilities and security devices, and have no permanently attached additions; or
3. Meet the requirements of subsection C of this section and the elevation and anchoring requirements for manufactured homes. (Ord. 4-2009, 6-8-2009)
Notes
| 1 | 1. Required for approval by FEMA. |
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