Founded in 1904, CertainTeed Corporation is a manufacturer of building materials. Based in Valley Forge, Pa., the firm offers products in there different categories, such exterior building products, interior building products and infrastructure. Its exterior building products includes siding, sheathing, fence, railing, decking, gypsum, ceilings, foundations and windows. CertainTeed Corporation is a subsidiary of Saint-Gobain, one of the leading industrial companies in the world. It caters to industrial ceramics/containers, reinforcements/flat glass, abrasives and building materials sectors.