In areas where the probability of termite infestation is "very heavy" as indicated in Figure R318.4, extruded and expanded polystyrene, polyisocyanurate and other foam plastics shall not be installed on the exterior face or under interior or exterior foundation walls or slab foundations located below grade. The clearance between foam plastics installed above grade and exposed earth shall be not less than 6 inches (152 mm). For crawl space applications, foam plastic shall be installed so as to provide a termite inspection gap of no less than 6 inches along the top of the foundation wall and foundation sill plate.
Exceptions:
S.C. Code Regs. § 8-1216