CORTEN: This product is produced by Ispat Sidbec Inc. and by other various steel mills around the world under the trade names of Corten, Kupten, Triacor, and others. It is a high strength cold rolled steel of architectural interest because after installation and exposure to normal weather the surface, in place, develops a pleasing iron oxide matte finish, which accents the appearance of any building on which it is use. The weathering process that occurs after installation eventually decreases and from that point on the finish acts as a protective coating for the base metal. Like many other architectural products with desirable features, some cautions must be exercised during installation. The roofing sheets are simple to install using the same methods as any other metal roofing sheets. However, care must be taken that the roof drains well so that no residual moisture can be trapped between two or more overlapping sheets. If moisture is trapped, the weathering process may continue where the moisture is trapped and the reaction will not stabilize as planned. The runoff of moisture from these panels will badly stain concrete or stucco. Be careful where the run-off is directed to prevent staining. Also, the fasteners used, either nails or screws, should be of non-plated stainless steel, anodized aluminum, copper, bronze or brass. Zinc and cadmium coated items are not suitable for use in contact with Corten Steel.