advice > advice 02
ADHESIVES FOR LARGE FORMAT TILES & PORCELAIN TILES
It is a common misconception that standard ready-mixed bucket adhesive is suitable for all sizes and types of tiles. Most manufacturers state that the maximum recommended size of tile to fix with ready-mixed adhesive is 250x200mm. This is because ready-mixed adhesives dry through the evaporation of the water that is contained in the adhesive causing it to harden. This means that if you are using a ready-mixed adhesive on a large format tile, the only way it can dry is through the joints. This will take a long time, and if the adhesive around the edge of the tile has set, the adhesive in the centre will not be able to dry fully. This has been proven in many situations where tiles have started to fall off the wall, after 3 years or more, and the adhesive in the centre of the tile is still wet. However, when a cement-based adhesive is mixed with water, a chemical reaction is activated, which, depending on the drying time of the particular adhesive, will make the adhesive harden. If a cement-based adhesive is used to fix large format tiles, this problem will not occur, so the best advice is, if you are in any doubt, use a polymer modified, cement-based adhesive.
The fixing of porcelain or fully vitrified tiles (or any non-absorbent tiles) using ready-mixed adhesives is also another area of concern. Because ready-mixed adhesives dry by evaporation, or the removal of the water content from the adhesive, if the tile is non-absorbent, no water can be "sucked" out through the biscuit of the tile. This will have the same effect as above with the adhesive behind the centre of the tile never being able to dry. Again, the best solution is to use a suitable cement-based adhesive, which will avoid all these possible problems. Always remember to check that whatever adhesive you are going to use, it is suitable for fixing the type and size of tile, and also that it is suitable for the background that you are fixing to.
Please Note - This advice is for general guidance only and may contain inappropriate information under particular conditions of use. We cannot accept responsibility for loss or damage due to the inappropriate use or the possibility of variations of working conditions and of workmanship outside our control.