Specifying the correct tile
Spanish tile manufacturers supply a huge and varied demand from both home and abroad, and so have built up considerable expertise. Here they share their knowledge on different types of tile, and when they are suitable to use.
The absorption of water in relation to the mass of the tile and the shaping technique (either pressing or extrusion) are the two criteria used to classify ceramic tiles in accordance with international ISO and European EN standards. The more highly pressed a tile, the less air it has in it, and therefore the lower the water absorption rate.
Non-vitreous: water absorption > 7 per cent
These tiles have a high water absorption rate and a low resistance to abrasion, making them particularly suitable for interior walls. Their high absorption ensures enhanced bonding to vertical surfaces, and because they are softer, they are easy to cut. They are available in a broad range of colours and designs due to the lower firing temperatures necessary for this type of tile. An additional advantage is the cheaper transport cost, due to their lighter weight.
Semi-vitreous: water absorption > 3 – 7 per cent
The denser body of these tiles means that they are suitable for flooring applications. The lower the water absorption, the more resistant to abrasion, so while a tile with a 7 per cent water absorption rate would be suitable for a residential application, heavier traffic areas should specify a tile with lower absorption rate. While this type of tile is suitable for outdoor use, it should not be used where there is a risk of extremely low temperatures, as its relatively high water absorption rates means it is not frost resistant.
Vitreous: water absorption > 0.5 – 3 per cent
Vitreous tiles are suitable for exterior use, and have generally been tested for frost resistance. They are ideal for areas that get wet, but don’t stay wet. Because they are still slightly porous, they have better adhesion properties and are easier to cut than tiles with a lower absorption rate.
Porcelain: water absorption < 0.5 per cent
Porcelain tiles are the densest and most compressed of all tile types. Therefore they have a very low level of water absorption and very high abrasion resistance. Because of this, they are the most suitable tiles for both interior and exterior use in areas subject to heavy traffic, whether people or vehicular (cars, shopping trolleys, wheeled luggage etc). They are also suitable for areas that are permanently submerged in water, including fountains, swimming pools and shower areas. Because of the tiles' low absorption, special polymer adhesives must be used for good bonding. Porcelain tiles are also suitable for use on walls, but special installation methods will be needed.
It is not just the water absorption rates that affect abrasion resistance, but also the type of glaze, which the Porcelain Enamel Institute (PEI) classifies into six groups, based on resistance to scratch tests.
Class 0: shows wear after 100 revolutions with grit
Suitable for wall use only. Technically unsuitable for flooring
Class 1: shows wear after 150 revolutions with grit
Suitable for residential and commercial wall use, and floors subject only to bare-foot traffic
Class 2: shows wear after 600 revolutions with grit
Suitable for wall and residential bathroom floors subject to soft-soled foot traffic
Class 3: shows wear after 1,500 revolutions with grit
Suitable for all residential walls and floors, and for light commercial use
Class 4: shows wear after 1,500-12,000 revolutions with grit
Suitable for medium commercial, light industrial and institutional use with moderate soiling
Class 5: shows wear after 12,000+ revolutions with grit
Suitable for extra heavy traffic and abrasive dirt. Chemically more resistant than other glazes
For further information on Spanish ceramic tile products, see www.spaintiles.info
For a list of manufacturers and retailers supplying the UK market contact the commercial office of the Spanish Embassy. Telephone + 44 (0) 20 7467 2389