Tile Over Plywood Subfloor

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.

Tile over plywood subfloor.

Begin by applying the thin skin adhesive to the plywood with a smooth trowel. Concrete board concrete board also called backer boardcomes in 1 4 and 1 2 thicknesses and is usually sold in 4 x 6 sheets. The go to product is 1 2 in. Thinset is the wet base that you first trowel on the plywood to make the tile.

Check for dips in the floor by sliding a 4 foot to 6 foot straight edge in different directions all around the room. Second the strength of wood boards isn t always consistent. There are two materials commonly used for laying ceramic on plywood or osb that are applied before the tile. For this project we are using the tavy thin skin system to prepare the surface for tile.

Fill seams in the subfloor with caulk. 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. A successful tile installation project requires a level surface. Cement board is inexpensive 10 or less for a 1 2 thick 3 x 5 sheet easy to install and sufficient for most installations.

Tips for laying tile on plywood subfloor for flooring use intervening sheets of plywood. Once the surface is completely covered cover the adhesive with the fiberglass based paper and smooth out any wrinkles or bubbles with a broad drywall knife. Uncoupling membranes aren t recommended for tiles smaller than 2 inches square and should not be used when covering old hardwood flooring due to adhesion problems. A 3 4 inch plywood subfloor on a joist structure with 24 inch spacing needs the extra thickness of cementboard or the floor will flex and the tiles will crack.

Void free underlayment grade panels which both stiffen the existing floor and provide uniform support to prevent cracks in the tile above. 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. Use the right. For residential use one form of underlayment the tile council of north america s handbook allows is plywood over joists that are 16 in.

First changes in humidity make solid wood shrink swell and cup more than plywood. No matter how firm the subfloor. Use thinset with a higher latex content. 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.