An existing residential or non-residential building, substantial improvement, and associated additions within the SFHA meeting all other criteria of this chapter may be designed, modified, anchored, or elevated to prevent flotation, collapse, or lateral movement of the structure in accordance with the following:
(A) The building or improvements shall be elevated on crawl space, stilts, piles, walls, or other foundation that is permanently open to floodwaters and not subject to damage by buoyancy or hydrostatic pressures of the base flood or 100-year frequency flood by allowing the automatic entry and exit of floodwaters. Designs must either be certified by a licensed professional engineer or by having a minimum of one permanent opening on each wall shall be no more than one foot above grade and consists of a minimum of two openings. The openings must have a total net area of not less than one square inch for every one square foot of enclosed are subject to flooding below the base flood elevation.
(B) The foundation and supporting members shall be anchored and aligned in relation to flood flows and adjoining structures so as to minimize exposure to known hydrodynamic forces such as current, waves, ice and floating debris.
(C) All areas below the flood protection elevation shall be constructed of materials resistant to flood damage. The lowest floor (including basement, crawlspaces, and walk-out basements) and all electrical, heating, ventilating, plumbing, air conditioning equipment, utility meters, and other service facilities shall be designed and/or located at or above the flood protection elevation and to prevent water from entering or accumulating within the components during conditions of flooding. Water and sewer pipes, electrical and telephone lines, submersible pumps, and other waterproofed service facilities may be located below the flood protection elevation.
(D) No area below the flood protection elevation shall be used for storage of items or materials.
(E) Manufactured homes and travel trailers to be installed on a site for more than 180 days, shall be elevated on a permanent foundation to or above the flood protection elevation and securely anchored to an adequately anchored foundation system; and, shall be anchored to resist flotation, collapse, or lateral movement by being tied down in accordance with the Rules and Regulations from the Illinois Mobile Home Tie-Down Act issued pursuant to 77 Ill. Adm. Code 870. Methods of anchoring may include, but are not to be 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.
(F) Recreational vehicles shall be located outside of all regulatory floodplain and floodway.
(G) The building may be constructed with a crawlspace located below the flood protection elevation provided that the above conditions are met as well as the following conditions:
(1) The interior grade of the crawlspace below the flood protection elevation must not be more than two feet below the lowest adjacent exterior grade.
(2) The interior height of the crawlspace measured from the interior grade of the crawl to the top of the foundations wall must not exceed four feet at any point.
(3) An adequate drainage system must be installed to remove floodwaters from the interior area of the crawlspace within a reasonable period of time after a flood event.
(4) Utility systems within the crawlspace must be elevated above the flood protection elevation.
(Ord. 3187, passed 1-22-19) Penalty, see § 152.999