Tile Materials & Finishes
Ceramic: A tile consisting of mixtures of clay, which are pressed and kiln fired at high temperatures, to give a hard ‘bisque or biscuit’. The ‘biscuit’ has a relatively high degree of absorbency enabling the adhesive to bond fairly easily. Ceramics may be left unglazed but are more often glazed to give more decorative options as well as physical benefits. This includes terracotta and quarry tiles. Ceramic tiles are generally not considered suitable for external use.
Porcelain: Porcelain tiles are made from a different blend of clay, and a manufacturing process similar to ceramics. This controls shrinkage and water use and results in a very dense, hard-wearing tile with an absorbency of less than 0.5%, suitable externally for commercial projects as well as for swimming pools and areas subject to frost. ‘Full bodied’ porcelain doesn’t show wear as there is no upper glaze. They are much more affordable and are nowadays also used in domestic installations.
Vitrious (fully vitrified and semi-vitrified): Similar in manufacture to ceramic tiles, but incorporating different clays to provide tiles that are harder, denser and less absorbent. They may be fired for longer and at higher temperatures than ceramics. The term vitreous simply means ‘glass like’. The classification for ‘fully vitrified’ is a tile with less than 3% water absorption. Fully vitrified tiles require the use of a polymer modified adhesive and may be used externally in areas for spas and swimming pools. Semi-vitreous tiles have a water absorption between 3-7%.
Terrazzo: Either pre-manufactured or laid in-situ, terrazzo consists of granite and marble chips in a Portland cement, or sometimes epoxy resin binder. They can be polished to give a low absorbent and high strength tile suitable for commercial use.
Agglomerate (quartz):This type of tile is manufactured by mixing graded pieces of granite and marble with cement and resins to give a pre-formed tile. They generally have low absorption. These tiles are sometimes referred to as quartz. For use of these type of tiles with underfloor heating always consult the manufacturer for guidance. Glass: Manufactured from glass, and available in many striking opaque colours. Traditionally manufactured in small sizes and often on mosaic backings, they are now available in much larger formats. They are very hard and offer extremely low porosity. There are presently no British or European standards covering glass tiles so it is always worthwhile contacting the manufacturer for adhesive recommendations. Typically a minimum of a C2 classification is required but some decorative tiles may require resin based adhesives.