What you need to do before tiling on wood

"Laying tiles directly onto floorboards is a no-no, says Mark Irving, Building expert Mark Irving, from Build & Plumb, "You can't lay tiles directly onto wooden floorboards as the individual floorboards are susceptible to movement, which can result in the cracking of the tiles and grout." If you have hardwood or MDF over the floorboards, these are not ideal choices as they absorb water, which can lead to issues later on."

"You can tile onto plywood, but it requires a minimum depth of 18mm and must be securely fastened to joists or the subfloor. You'll need to check that there is no movement. Additionally, plywood will need to be primed with a suitable primer, such as the BAL APD Primer, available on Amazon. Any joints will also need to be filled with a silicone sealant to prevent tile adhesive from seeping into the gaps."

Wooden floors expand and contract, so they require proper preparation before tiling to avoid cracked or lifted tiles. Tiles must not be laid directly onto individual floorboards because board movement can crack tiles and grout. Hardwood and MDF over floorboards absorb water and are poor substrates. Plywood can be used if at least 18mm thick, securely fastened to joists or subfloor, and checked for movement. Plywood joints must be filled and the surface primed with a suitable primer. Installing a cement backer board between tiles and wooden flooring provides a stable, flat surface that reduces cracking risk.

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