Building rules for coastal high hazard areas

In addition to the general development standards, the following standards shall be applicable in the coastal high hazard area. (a) (1) All new construction or substantial improvements of residential and nonresidential structures shall be elevated on pilings or columns so that the bottom of the lowest horizontal structural member of the lowest floor (excluding the pilings or columns) is elevated to or above the base flood elevation. (2) Piles or column foundations and structures attached thereto shall be anchored to resist flotation, collapse and lateral movement due to the effects of wind and water loads acting simultaneously on all building components. Wind and water loading values shall each have a 1 percent chance of being equaled or exceeded in any given year. (b) (1) All new construction or substantial improvements shall have the space below the lowest floor free of obstructions or constructed with breakaway walls, open wood latticework, or insect screening intended to collapse under wind and water loads without causing collapse, displacement, or other structural damage to the elevated portion of the structure or supporting foundation. (2) Such enclosed space shall not be used for human habitation and shall be used solely for parking of vehicles, building access, or storage. (3) A breakaway wall shall have a design-safe loading resistance of not less than 10 and not more than 20 pounds per square foot, or a licensed architect or engineer shall certify that the breakaway wall shall collapse from a water load less than that which would occur during the base flood. (c) The use of fill for structural support of buildings shall be prohibited. (d) All new development shall be constructed landward of the reach of the mean high tide. (e) Human alterations of sand dunes and native mangrove stands which would increase potential flood damage shall be prohibited. (f) A licensed architect or engineer shall develop or review the design, specifications, and plans and certify that the design and methods of construction are in accordance with accepted standards of practice for meeting the provisions of this chapter, and that any development in the coastal high hazard area, including structures and improvements, would not affect the base flood nor aggravate existing flood-related erosion hazards.