Large format tiles have changed the way tilers go about tiling walls and floors, but no matter how we resist change, tiles are getting bigger and bigger. Here, Matthew Mowforth and Gary Haigh, ARDEX Group UK training and technical support managers, discuss a few things to be mindful of when choosing or working with large format tiles.
For large format tiles, with a surface area >3,600sqcm (with no tile edge >1,200mm) the first thing to be mindful of is the placement of ceramic tiles, leaving adequate joint widths between the tiles. Joints between ceramic wall tiles should be at least 2mm wide. British Standards advises for large format tiles, a minimum joint width of 3mm is required. In the case of ceramic panels, the joint width should be increased pro-rata to the size of the panel. Butt-jointing tiles is not advised.
The joint widths between tiles should take into account the type, size and permissible dimensional tolerances of the tiles. A grout must also be chosen which is suitable for the expected use of the tiling whilst in service.
The second thing to be mindful of is the selection of the correct adhesive for the type and size of ceramic tile to be installed – especially large format tiles and ceramic panels. For the installation of large format porcelain tiles, use a suitable improved cementitious, highly polymer-modified tile adhesive
Also, it would be advantageous to use tile adhesives with additional properties of extended open time, and reduced slip resistant properties (for wall tiling with larger wall tiles). The need for solid bed fixing is a must, as poor contact will potentially lead to tiles cracking and/or debonding. Do not spot fix ceramic tiles with tile adhesive.
Tiles should be solidly supported by the tile adhesive. Air pockets or voids beneath the tiles are potential points of weakness due to an impact from a heavy object. Tile adhesive should always be applied to the wall using a suitable notched trowel as per the adhesive manufacturer’s recommendations. In addition, back butter large format tiles by applying a thin bed of adhesive on the back of the tiles to fill in any deep keys or heavily buttoned back tile profiles before placing into the adhesive ribs, applied using the correct notched trowel to the wall.
However, when using some pourable tile adhesives, back-buttering may not be required – as long as the surface is level and flat. Occasionally lift a tile to check adhesive contact to check for any voids beneath the tiles.
You should also be mindful of preparing the background i.e. pre-levelling of the floor or wall as per the adhesive manufacturer’s recommendations prior to using the tile adhesive. This will help ensure you have a flat surface to tile and help ensure solid bed fixing is achieved.
There are a number of options for floor levelling from all-rounders, to fast levellers. Ensure you choose the right levelling compound for your application.
Be aware that some levelling compounds may take longer to dry than anticipated, so use a trusted product with the technology to dry as stated on packaging and technical datasheets. Always check those technical datasheets for accurate mixing instructions and curing times!
Adhesive and levelling manufacturers like the ARDEX Group UK have to continuously develop our products to suit new types and sizes of tiles. Adhesives developed 15 years ago were developed with a lot of different types of tiles in the marketplace. New products are developed for the tiles in the marketplace today.
Be mindful of this when choosing the right adhesive for the tile being installed.