pieces of ceramic roofing material made of fired clay, a cement-sand mortar, or a lime-sand mortar processed in an autoclave (silicate tile). The most common clay tile is made from plastic clays having a low fusion point (sometimes with the addition of a fireclay).
Depending on the shape and the molding method, roofing tile may be classified as grooved (both pressed and strip types) and flat (strip type); a ridge tile is also produced to cover the ridge of a roof. Depending on the composition of the clay and the firing method, tile may have a natural color ranging from brick red to a yellow-gray. For decorative purposes tile is sometimes coated with a colored glaze. Cement tile can be colored with a weatherproof pigment through its cross section or on its surface. The advantages of roofing tile are its durability, fire resistance, impermeability to water, frost resistance, and low maintenance costs (periodic painting is not required); the disadvantages include brittleness and relatively high weight. Tile roofs should have a steep slope (more than 30°) in order to drain off water.