The minimum thickness of 0.33 mm stated in Sentence 9.27.11.1.(1) refers to the total thickness of the materials, i.e., the combination of the minimum thickness of the base steel (0.29 mm) and the minimum coating thickness required by CSSBI 23M, “Standard for Residential Steel Cladding”. Note that the terms “siding” and “cladding” are often used interchangeably.