Metal is one of the few materials that can be used for both pitched roofs and flat roofs. Flat or low-slope roofs can be covered with steel, aluminum, zinc, or copper just like pitched roofs. However, metal shingles are not practical for flat roofing and so roofers recommend standing-seam and screw-down metal panels. While metal can be an expensive option in the short term, superior durability and simple maintenance of metal roofs saves money in the long term. Metal roofs are also one of the most environmentally sound roofing options.