A. Application Of Provisions: In addition to the damage prevention requirements of section 11-1-6 of this chapter, all buildings to be located in the SFHA shall be protected from flood damage below the FPE. This building protection requirement applies to the following situations:
1. Construction or placement of a new building valued at more than one thousand dollars ($1,000.00).
2. Structural alterations made to an existing building that increase the floor area by more than twenty percent (20%) or the market value of the building by more than fifty percent (50%).
3. Reconstruction or repairs made to a damaged building that are valued at more than fifty percent (50%) of the market value of a building before the damage occurred.
4. Installing a manufactured home on a new site or a new manufactured home on an existing site. This subsection A4 does not apply to returning a manufactured home to the same site it lawfully occupied before it was removed to avoid flood damage.
5. Installing a travel trailer on a site for more than one hundred eighty (180) days. (1999 Code § 12.15)
B. Methods Of Protection: The building protection requirement may be met by one of the following methods. The code official shall maintain a record of compliance with these building protection standards as required in subsection 11-1-3B of this chapter. (1999 Code § 12.15; amd. 2005 Code)
1. A residential or nonresidential building may be constructed on permanent landfill in accordance with the following:
a. The fill shall be placed in layers no greater than one foot (1') deep before compaction.
b. The lowest floor (including basement) shall be at or above the FPE. The fill should extend at least ten feet (10') beyond the foundation of the building before sloping below the FPE.
c. The fill shall be protected against erosion and scour during flooding by vegetative cover, riprap or bulkheading. If vegetative cover is used, the slopes shall be no steeper than three (3) horizontal to one vertical.
d. The fill shall not adversely affect the flow of surface drainage from or onto neighboring properties.
2. A residential or nonresidential building may be elevated in accordance with the following:
a. The building or improvements shall be elevated on crawl space, walls, stilts, piles or other foundation; provided, that the walls have permanent openings no more than one foot (1') above grade and that the walls and floor are not subject to damage by hydrostatic pressures associated with the base flood.
b. The foundations and supporting members shall be anchored and aligned in relation to flood flows and adjacent structures so as to minimize exposure to known hydrodynamic forces such as currents, waves, ice and floating debris.
c. All areas below the FPE shall be constructed of materials resistant to flood damage. The lowest floor (including basement) and all electrical, heating, ventilating, plumbing and air conditioning equipment and utility meters shall be located at or above the FPE. Water and sewer pipes, electrical and telephone lines, submersible pumps and other waterproofed service facilities may be located below the FPE.
3. Manufactured homes and travel trailers to be installed on a site for more than one hundred eighty (180) days shall be elevated at or above the FPE in accordance with subsection B1 or B2 of this section and anchored to resist flotation, collapse or lateral movement by being tied down in accordance with the rules and regulations for the Illinois mobile home tie down act issued pursuant to 210 Illinois Compiled Statutes 120/1 through 120/6.
4. Only a nonresidential building may be floodproofed in accordance with the following:
a. A registered professional engineer shall certify that the building has been designed so that below the FPE, the structure and attendant utility facilities are watertight and capable of resisting the effects of the base flood. The building design shall take into account flood velocities, duration, rate of rise, hydrostatic and hydrodynamic forces, the effects of buoyancy and impacts from debris and ice.
b. Floodproofing measures shall be operable without human intervention and without an outside source of electricity.
5. In the case of garages or sheds constructed ancillary to a residential use, wet floodproofing meeting the following conditions shall be sufficient:
a. The garage or shed must be nonhabitable; and
b. The garage or shed must be used only for the storage of vehicles and tools and cannot be modified later into workshops, greenhouses, living areas, etc.; and
c. The garage or shed must be located outside of the floodway; and
d. The garage or shed must be on a single-family lot and be accessory to an existing principal structure on the same lot; and
e. Below the base flood elevation, the garage or shed must be built of materials not susceptible to flood damage as provided in FEMA technical bulletin 2-93; and
f. All utilities, plumbing, heating, air conditioning, electrical, etc., must be elevated above the flood protection elevation; and
g. The garage or shed must have at least one permanent opening on each wall no more than one foot (1') above grade with one square inch of opening for every square foot of floor area as provided in FEMA technical bulletin 1-93; and
h. The garage or shed must be less than seven thousand dollars ($7,000.00) in market value or replacement cost, whichever is greater, or less than six hundred (600) square feet; and
i. The structure shall be anchored to resist flotation and overturning; and
j. All flammable or toxic materials (gasoline, paint, insecticides, fertilizers, etc.) shall be stored above the flood protection elevation; and
k. The lowest floor elevation should be documented and the owner advised of the flood insurance requirements. (1999 Code § 12.15)
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