When used as an underlayment the plywood sheets are laid over the osb or plywood subfloor for a two layer base.
Tile over wood subfloor bathroom.
Don t lay tiles on a concrete slab with cracks that appear to be spreading or irregularities that prevent you from leveling it.
This guide will show you how to prepare your subfloor for a tile installation project to ensure that it s fit to support ceramic or porcelain tile.
The subfloor must be free of moisture damage including rot and sponginess and must be securely fastened to the joists and squeak free.
According to backer board manufacturers and tile setters installing backer board directly over an old solid wood subfloor is risky for a couple of reasons.
Generally this only refers to a layer of plywood but in the case of bathrooms it includes an underlayment of concrete backerboard as well.
It uncouples or releases the bond between plywood and tile mortar allowing each surface to move independently of each other.
Preparing a subfloor is an essential step for installing floor tile it provides a level surface that will allow the tiles to properly stay in place.
A tight unmoving bond between mortar and subfloor causes cracking.
Installed directly over the joists the primary function of a subfloor is to create a flat solid surface for the finished flooring to rest on.
An uncoupling membrane does exactly what the name says.
Second the strength of wood boards isn t always consistent.
First changes in humidity make solid wood shrink swell and cup more than plywood.
If installing over an appropriate wood surface sand the wood to make it smoother and remember that the installation will work better over a subfloor at least 1 1 8 inches thick.
Installing tile over a wood subfloor is a lot easier today than it was when i started my remodeling career.
While i prefer using 1 2 cement backer board over a plywood subfloor you may be able to get by with 1 4 backer board instead.
The old fashioned mud method of floating a thick mortar bed in preparation for the tile has given way to using cement backer board over a plywood subfloor.
Tape over holes and cracks in the wood subfloor or slab before pouring on the self leveling tile underlayment to keep it from seeping through and leaving indentations.
If the tile is being installed in a bathroom consider applying an isolation membrane over your wood subfloor to further protect against expansion and contraction.