I am redoing my bathroom and figuring out how to do the floor.
Previously it had lino on top of 26mm of tongue and groove foam-backed chipboard, which also locked into the hall floor. This chipboard was rotten and had to be removed. It sat directly on solid concrete, which is the structural floor of my flat.
I now want to put down ceramic tiles, but am unsure what to put between the tiles and the concrete (tiling directly onto the concrete is not an option)
Many places I have looked suggest plywood but they assume you already have wood underneath to affix it to, and I think that without that it may expand too much in the humidity.
Another option in concrete backer boards, but would I still need wood underneath them to hold them together?
I would also like to include a new foam layer for insulation/sound proofing.
Can anyone recommend a solution that will ensure my tiles will stay fixed down and not crack?
Thanks for reading
Best Answer
No no no. You do not put a subfloor on good concrete. You are then allowing for a moisture sandwich (which is bad). Buy a modified thinset, put tiles on thinset, grout, then you are done.