The Spruce / Kevin Norris
Plywood is a standard subfloor for floor coverings likelaminateorluxury vinyl tile.
But can you use plywood below ceramic or porcelain tile?
The best direct underlayment for tile on plywood is cement board or an uncoupling membrane.
The Spruce / Kevin Norris
The solution is to add an intervening layer that uncouples the tile from its base.
Uncoupling tile membranes prevent moisture migration.
Membranes are lightweight and easy to work with but expensive.
The Spruce / Kevin Norris
Tip
Acement boardsuch as Durock or HardieBacker can be used as an alternative to an uncoupling membrane.
Do not install tile directly on the plywood subfloor itself.
Exterior grade orplywoodshould be used for thesubstrate.
The Spruce / Kevin Norris
Never use veneer-bond plywood.
Leaving a gap allows for this inevitable expansion.
see to it that all screw heads are screwed flush with the level of the plywood.
The Spruce / Kevin Norris
If the plywood flexes, add more screws to the boards.
If that doesn’t do it, then the floor joists may be faulty.
Shoring up the joists from below by sistering them with 2x10s or 2x8s is one way to strengthen joists.
The Spruce / Kevin Norris
Joints of the top layer should be well away from the joints of the bottom layer.
Avoid having two joints on top of each other.
Trowel On the Modified Thinset
Use the notched trowel to apply thinset to the plywood.
The Spruce / Kevin Norris
Be sure to use a modified thinset mortar for this first layer.
Lay Down the Membrane
Press the uncoupling membrane into the wet thinset.
Do not let the thinset dry; work quickly.
The Spruce / Kevin Norris
Trowel on the Unmodified Thinset
Switch batches in the bucket from modified thinset to unmodified thinset.
Use the notched trowel to apply the unmodified thinset to the top of the uncoupling membrane.
drop in the Tile
Apply the tile to the layer of unmodified thinset.
The Spruce / Kevin Norris
Use plastic tile spacers to keep the tiles separate.
Apply the Grout
Use the rubber float to apply the grout to the surface of the tile.
Pull the grout in long sweeps diagonally across the tile.
The Spruce / Kevin Norris
Remove as much grout as possible from the tile.
Be careful not to dig into the grout between the seams.
Remove the Grout Haze
Mix grout haze remover in a clean bucket.
The Spruce / Kevin Norris
Apply the haze remover with a sponge to remove the haze from the tile.
Higher latex content is essential for bonding to plywood.
A qualityunmodified thinsetshould be used and mixed with a latex additive.
The Spruce / Kevin Norris
Set a dinner plate on the plywood.
Set a cereal bowl on the plate.
With a separate container, fill the bowl to the rim.
Then, walk on the plywood around the bowl.
You should see some ripples from vibration, but the water should not spill onto the plate.
Plywood does not need to be primed before tiling.
A plywood underlayment for tile should be 1/2- to 3/4-inch thick.
A cement backer board is a good underlayment for tile floors.
Since it is a masonry product, it is less prone to deterioration than wood.
