Life of 20-30 years. Not easily recycled at end of useful life. Weigh approximately 230 pounds per square. 3.0 Metal roofing products Can be made to give shingle appearance Most metal roofing, including standing-seam, contains recycled metal. Metal roofing used primarily for agricultural buildings is lower in cost, but requires premium metal coatings, factory-finished panels, or watertight construction detailing when used for housing.
Protection is lost when the oxidation process uses up the zinc, and the steel underneath can rust.
On low-sloped roofs in wet climates, coating loss and rust can show up in five years. Aluminum coatings are superior to zinc, carrying warranties up to twenty years. They are inert, and do not degrade over time. 3.2 Paint Only use factory applied paint. Polyester resin finishes offer least durability.