Concrete tiles are made of portland cement, sand and water in varying proportions. The material is mixed and extruded on molds under high pressure. The exposed surface of a tile may be finished with cementitious material colored with synthetic oxide additives. The tiles are cured to reach the required strength. They generally have lugs on their undersides for anchoring to batten strips. There are additional waterlocks or interlocking ribs on the longitudinal edges that impede movement and prevent water infiltration.
As with clay tile, there are a wide variety of profiles, styles, finishes and colors available. Color may be added to the surface of a tile or dispersed throughout (color through). Special texture may be added in surface treatment. Each type of tile roof system may make use of separate ridge, hip, hip intersection, gable end and finial accessory tiles of various shapes in addition to field tiles.
Many different types and combinations of securement methods are used for the various types of roof tile. To select a method of securement, many conditions need to be considered: wind, deck type, seismic considerations, slope, building codes, local practices and manufacturer recommendations. Fasteners should be made of noncorrosive materials that will remain serviceable in the intended environment for the roof’s design life.