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5. All new construction and substantial improvements with fully enclosed areas below the lowest floor <br />(excluding basements) are subject to the following requirements. Enclosed areas below the base flood <br />elevation, including crawlspaces, shall: <br /> <br />a. Be designed to automatically equalize hydrostatic flood forces on walls by allowing for the entry and <br />exit of floodwaters; <br />b. Be used solely for parking, storage, or building access; <br />c. Be certified by a registered professional engineer or architect to meet or exceed all of the following <br />minimum criteria: <br />i. A minimum of two openings, <br />ii. The total net area of non-engineered openings shall be not less than one square inch for each <br />square foot of enclosed area, where the enclosed area is measured on the exterior of the <br />enclosed walls, <br />iii. The bottom of all openings shall be no higher than one foot above grade, <br />iv. Openings may be equipped with screens, louvers, or other coverings or devices; provided, <br />that they shall allow the automatic flow of floodwater into and out of the enclosed areas and <br />shall be accounted for in the determination of the net open area; <br /> <br />6. Construction where the crawlspace is below grade on all sides may be used. Designs for meeting these <br />requirements must either be certified by a registered professional engineer or architect, or must meet the <br />following standards, consistent with FEMA Technical Bulletin 11-01 for crawlspace construction: <br /> <br />a. A minimum of two openings having a total net area of not less than one square inch for every square <br />foot of enclosed area subject to flooding shall be provided; <br />b. The bottom of all openings shall be no higher than one foot above grade; <br />c. Openings may be equipped with screens, louvers, or other coverings or devices; provided, that they <br />permit the automatic entry and exit of floodwaters; <br />d. Interior grade of the crawlspace shall not exceed two feet below the lowest adjacent exterior grade; <br />e. The height of the crawlspace when measured from the interior grade of the crawlspace (at any point <br />on grade) to the bottom of the lowest horizontal structural member of the lowest floor shall not <br />exceed four feet; <br />f. An adequate drainage system that removes floodwaters from the interior area of the crawlspace <br />shall be provided; <br />g. The velocity of floodwaters at the site shall not exceed five feet per second for any crawlspace. For <br />velocities in excess of five feet per second, other foundation types shall be used; and <br />h. Below-grade crawlspace construction in accordance with the requirements listed above will not be <br />considered basements for flood insurance purposes. However, below-grade crawlspace construction <br />in the special flood hazard area is not the recommended construction method because of the <br />increased likelihood of problems with foundation damage, water accumulation, moisture damage, <br />and drainage. Applicants shall be advised that buildings constructed with below-grade crawlspaces <br />will have higher flood insurance premiums than buildings that have the preferred crawlspace <br />construction (the interior grade of the crawlspace is at or above the adjacent exterior grade); <br /> <br />7. A garage attached to a residential structure, constructed with the garage floor slab below the base flood <br />elevation, or a fully enclosed space beneath a residential structure that does not constitute a basement <br />may be constructed to wet floodproofing standards; provided, that: <br /> <br />a. The garage or enclosed space shall be constructed with unfinished materials, acceptable for wet <br />floodproofing to two feet above the base flood elevation or, where no BFE has been established, to <br />two feet above the highest adjacent grade; <br />b. The garage or enclosed space shall be designed and constructed with flood openings to <br />automatically equalize hydrostatic flood forces on exterior walls by allowing for the automatic entry <br />and exit of floodwaters, in full compliance with the standards in subsection (A)(5) of this section; <br />c. Electrical, heating, ventilation, plumbing, and air-conditioning equipment shall be elevated to one <br />foot above the level of the base flood elevation. Where the base flood elevation is not available, the <br />electrical, heating, ventilation, plumbing and air-conditioning equipment shall be elevated to one <br />foot above the highest adjacent natural grade (within five feet) of the building site;