A metal roof is a roofing system made from metal pieces, or tiles. Metal roofs protect buildings. Advantages: Very durable in cold weather High percentage of recycled material and are 100% recyclable Metal roofing can be used for residential and commercial buildings. The same material used for metal roofs can be used for siding as well. Metal roofing can also be applied over an existing roof. Roofing materials made from stainless steel, zinc or copper will rarely require maintenance over their lifetime. These materials commonly last over a century. To wash a metal roof, using water with a hose or power washer is sufficient; for more resistant dirt, a brush with detergent or trisodium phosphate is effective. Abrasive cleaners and tools such as wire brushes and steel wool, however, may damage the protective coating on a metal roof.