Tiling Onto Wooden Floors
Whether you're fixing natural stone Carrara marble tiles or Mondo Grey Cement-Effect porcelain tiles, tiling onto wooden floors needs different preparation from other materials such as concrete. The key reason is the movement, or 'bounce', inherent to wood, which needs to be taken into account.
The tiling surface you're faced with will generally be floorboards, chipboard, or plywood. It's inadvisable to attempt to fix you kitchen floor tiles directly onto floorboards as they are likely to be uneven and have stain or varnish on them. These 'contaminants' will prevent the tile adhesive from bonding with the floor, which will over a period of time cause the floor tiles to crack or come loose. The same will occur if attempts are made to fix floor tiles directly to chipboard, as the glues in the chipboard may react with adhesive and prevent the floor tile adhesive from setting.
Marine-grade plywood boards are the ideal wooden substrate to fix tiles to. Before fixing the plywood, the surface below must be sound and solid, so replace any damaged parts of floorboards or chipboad. When preparing to fix bathroom floor tiles in a room where there has been a water leak, it's essential to make sure the substrate has dried out and still has sufficient strength to support the weight of floor tiles.
Floorboards can often run from a landing area into a bathroom, or in hallways in older terraced properties from one house to a neighbouring house – ensure these overlapping boards are secure too before fixing floor tiles. The minimum thickness of plywood overlay should be 12mm, but generally the thicker the better to improve rigidity. The boards should be screwed, not nailed, to the substrate underneath at 10-15cm intervals to give a solid surface on which to tile.
If the original floorboards or chipboard has deteriorated beyond repair, replacing them with 18-22m plywood is a good option. Whilst you’re replacing the substrate, it is prudent to fix battens between joists to reinforce the structure, particularity if you're fixing heavy natural stone floor tiles such as Jura limestone.
Prior to fixing the floor tiles onto your new surface, we recommend priming your new floor with a suitable primer such as Kerakoll Primer A, to help the adhesive bond to the floor. If the floor area you're tiling is more than 9m in one direction, or if the area is part concrete part wood, to help prevent tiles cracking fitting a sub layer such as Kerakoll Idrobuid Tex antifracture matting is required. The matting is less than 1mm thick and can be fixed with a 4-6mm toothed trowel, creating a minimal but sufficient think bed of adhesive.
And there you have it – everything you need to know about tiling onto wooden floors.