SHEET STEELS FOR LOW SLOPE ROOFING.

Three types of coated sheet steels - galvanized, aluminum coated, and aluminum-zinc coated (Galvalume) are a significant force behind standing seam's market penetration for low-slope, non-residential roofing. The purpose of this article is not to recommend one type of coating over another, but merely point out the options available. Standing seam roofing is made from cold rolled, low carbon sheet steel, typically 0. 019-inch to 0. 024-inch thick. A hot-dip metallic coating is added to provide the long term weather protection needed for atmospheric exposure. Zinc, aluminum, or a combination of both usually composes the metallic coating, which is metallurgically bonded to the steel substrate by passing the sheet steel through a molten bath.