Roof tiles are overlapping tiles designed mainly to keep out precipitation such as rain or snow, and are traditionally made from locally available materials such as clay or slate. Later tiles have been made from materials such as concrete, glass, and plastic.
Roof tiles can be affixed by screws or nails, but in some cases historic designs utilize interlocking systems that are self-supporting. Tiles typically cover an underlayment system, which seals the roof against water intrusion.[1]