Porcelain tiles are ceramic tiles with a water absorption rate of less than 0.5 percent that are used to cover floors and walls. They can either be unglazed or glazed.

Large-scale production of porcelain tile is undertaken in many countries, with the major producers being China, Italy, Spain and Turkey. There are also countries undertaking small-scale production, such as Australia and strong growth in Brazil.

The hardness of the tile can be rated from zero to five according to ISO 10545-7 (also, ASTM C1027) test for surface abrasion resistance of glazed tile, and this can be used to determine suitability for various end use conditions.

The dense, hard surface of porcelain has made polishing a viable alternative to a glazed surface. This means that a tile can be fired, then a polish cut into the surface, creating a shine without a glaze.

Porcelain is denser and therefore heavier to handle; it is generally more expensive. Being harder, it is harder to cut and drill, which may make fitting harder and more expensive. Polished porcelain may need sealing, where ordinary glazed tiles do not.

Specialised cements are necessary for installation of porcelain tiles, and in the US specifications are set by the Tile Council of America, and supported by the Tile Contractors Association Porcelain, being denser and heavier than ordinary ceramic tiles, needs a stronger adhesive to hold the weight on walls. Therefore typical ready-mix adhesives are not recommended for porcelain.

When porcelain is first made, it is not absorbent, but the polishing process for making the unglazed surface shiny cuts into the surface, making it more porous and prone to absorbing stains, in the same way as natural stone tiles do. Unless they have a suitable, long-lasting treatment put on by the manufacturer, such as nanotech treatment, polished porcelain tiles will need sealing. Porcelain sealer’s are either water-based, which is cheaper, but does not last as long, or solvent-based.