The plywood will expand and contract at a different rate as the tile causing cracks to develop in the grout lines or tiles over time.
Ceramic tile plywood subfloor installation.
If needed sand the plywood down to level the subfloor.
Remember that you need a very flat surface to work on.
Tile floors are heavy and tile is a hard material.
For this reason ceramic and porcelain tile floors can be considered somewhat delicate despite the inherent strength of the material.
This will cause either the tile itself to crack and even come loose or cause the grout to crack inside the joints.
However you re not out of the woods.
Laying tile on plywood.
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.
While you can lay tile directly over a concrete slab using thin set adhesive don t make the mistake of applying tile directly to a plywood subfloor.
The detail shown is essentially tcna s f150 method with the addition of an uncoupling crack isolation membrane.
Installing over wood.
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.
Because of issues of moisture movement and adhesion ceramic tile will work well with certain types of subfloor underlayment systems and can go dramatically wrong with other subfloor materials.
Chipboard cushioned vinyl flooring particle boards of any type oriented strand board osb interior grade plywood tongue and groove planking and hardwood floors are unsuitable substrates for direct installation of ceramic tile.
A plywood subfloor must be structurally sound and able to support the installation.
Concrete expands and contracts and that type of movement can also crack the tiles and the grout.
The tcna spec shows this detail with the tile bonded directly to the plywood but few tile experts recommend doing this.
Plywood substrate alternatives.
Backerboard does not shrink or expand when it comes into contact with water mortar and grout both contain water.
To install ceramic tile over wood the wood surface must be structurally sound enough to support the weight of the tile.
It will break or dislodge if the surface bends under the load.
A poor ceramic installation will delaminate from the subfloor split at the grout lines or worse crack directly across the tile.
The safest most prudent course is to install tile on top of a cement backerboard such as durock wonderboard or hardiebacker.
When installing a ceramic tile floor on a concrete subfloor you don t have to worry about flexing as long as the concrete slab is at least 1 1 8 inch thick which most slabs are.
Tile installation standards are established by tcna the tile council of north america.
One question that folks new to ceramic tile frequently ask is whether they can lay the ceramic directly on top of a plywood or osb subfloor using a thinset cement or liquid nails to glue down the tile to the wood.
Plywood or osb flakeboard can expand and contract at too high a rate to be a stable foundation for tile.
