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Porcelain
Porcelain tile is tile made from 50 percent feldspar and 50 percent high quality clay that is fired at extremely high temperatures. Porcelain tiles are fired at 2200 degrees Fahrenheit, as opposed to the 1800 degrees Fahrenheit firing temperature of ceramic tiles, which allows the tile to be much more impervious to water than ceramic tile. Porcelain tiles are pressed at 6000 pounds of pressure per square inch, rendering them extremely dense and strong. To be considered porcelain, the tile must have a water absorption rate of 0.5 percent or less; in contrast, ceramic tile typically has a water absorption rate of 3 percent or higher. Various terms are used in the European Industry to qualify the makeup of Porcelain tiles. Unglazed/full bodied – The characteristics of full bodied porcelain are the same throughout the tile, unlike glazed porcelain where the technical characteristics i.e. slip resistance and wear rating, are affected by the glaze. Full bodied porcelain is extremely hard wearing and suitable for heavy traffic areas.

Single charged/loaded – Sometimes referred to as single powder loading, this method of decoration works by applying chemical salts to the tile before firing. The reaction of the salts to the porcelain during firing creates the aesthetic finish of the tile.

Double charged/loaded – These are produced in a similar way to single loaded porcelain, however a second layer of very fine powder is applied to the surface before firing and 2 layers of porcelain are pressed together to make the finished product.

Rectified and calibrated – rectifying the tiles (shaving the edges to form a sharp edge) is carried out for aesthetic purposes but also allows all tiles to calibrate to very accurate sizes.

Polishing – The polished finish is achieved in a similar way to polishing stone. Polishing wheels take a fraction of a mm from the surface of the tile to create the look. The action of the polishing wheels make the surface of the tile very slightly porous, which explains the use of wax to protect the tiles from marking during transit and the need for a coat of polished porcelain sealer when they are fixed.