Ceramic tile is a surfacing unit, relatively thin with respect to surface area, with a body of clay or a mixture of clay and other ceramic materials that has been fired above red heat. The tile should meet the requirements of the Recommended Standard Specification for Ceramic Tile, TCA 137.1, of the Tile Council of America, Inc., Princeton, NJ 08540.
Ceramic tile is referred to as glazed if it is given a surface finish composed of ceramic materials that have been fused into the body of the tile and that may be impervious, vitreous, semivitreous, or non vitreous. [Glazed tiles tend to be slippery, especially when wet. If this characteristic is undesirable (for example, for floors), then unglazed tile, which has a homogenous composition, or tile incorporating a dispersed abrasive should be used.] Impervious tile is required to have water absorption of less than 0.5% when tested as described in ASTM C373. Vitreous tile is required to have water absorption between 0.5 and 3%.
Ceramic tile is classified as wall, ceramic mosaic, quarry, or paver tile. Mosaic, paver, and quarry tile are generally used as floor coverings.
Wall tile is glazed and usually nonvitreous (water absorption greater than 3% but less than 18%). It has a body that is suitable for interior applications, although it is not expected to withstand impact. Flat wall tile is nominally 5⁄16 in thick. Rectangular in shape, it generally comes in nominal sizes of 41⁄4 x 41⁄4, 6 x 41⁄4, and 6 6 in. Also, trim units are available with various shapes necessary for completing an installation. These units include bases, coves, caps, curbs, angles, and moldings.
Ceramic mosaic tile is made of porcelain or natural clay. It may be glazed or unglazed, and if glazed, may be either plain or contain a dispersed abrasive. Nominal thickness is 1⁄4 in. Surface area is less than 6 in2. Available in rectangular, hexagonal, and other shapes, flat mosaic tiles come in nominal sizes 1 x 1, 2 x 1, and 2x 2 in. The tiles usually are mounted on sheets 1 ft by 2 ft, to facilitate tile setting.
Quarry tile is made by extrusion from natural clay or shale and is unglazed. It usually is 1⁄2 to 3⁄4 in thick. Surface area generally exceeds 6 in2.
Paver tile is similar to ceramic mosaic tile but is thicker, larger, and unglazed.
Thickness usually is 3⁄8 or 1⁄2 in. Nominal sizes generally are 4 x 4, 6 x 6, and 8 x 4 in.