Section 3285.504 - Skirting(a) Skirting, if used, must be of weather-resistant materials or provided with protection against weather deterioration at least equivalent to that provided by a coating of zinc on steel of not less than 0.30 oz./ft.2 of surface coated.(b) Skirting must not be attached in a manner that can cause water to be trapped between the siding and trim or forced up into the wall cavities trim to which it is attached.(c) All wood skirting within 6 inches of the ground must be pressure-treated in accordance with AWPA Standard U1 (incorporated by reference, see § 3285.4 ) for Use Category 4A, Ground Anchor Contact Applications, or be naturally resistant to decay and termite infestations.(d) Skirting must not be attached in a manner that impedes the contraction and expansion characteristics of the home's exterior covering.