Tile Over Plywood Subfloor

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.

Tile over plywood subfloor.

It should be fastened to the subfloor using thinset and then screwed down every 10 square. 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. Cement board is inexpensive 10 or less for a 1 2 thick 3 x 5 sheet easy to install and sufficient for most installations. 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.

Begin by applying the thin skin adhesive to the plywood with a smooth trowel. A successful tile installation project requires a level surface. 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. For residential use one form of underlayment the tile council of north america s handbook allows is plywood over joists that are 16 in.

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. Concrete board concrete board also called backer boardcomes in 1 4 and 1 2 thicknesses and is usually sold in 4 x 6 sheets. 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. Use thinset with a higher latex content.

The go to product is 1 2 in. Check for dips in the floor by sliding a 4 foot to 6 foot straight edge in different directions all around the room. While tile can be laid on plywood do not install tile directly onto. For this project we are using the tavy thin skin system to prepare the surface for tile.

Second the strength of wood boards isn t always consistent. Tips for laying tile on plywood subfloor for flooring use intervening sheets of plywood. Thinset is the wet base that you first trowel on the plywood to make the tile. 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.

First changes in humidity make solid wood shrink swell and cup more than plywood. If you find hollows and valleys you must fill them with a self leveling underlayment. Fill seams in the subfloor with caulk. Void free underlayment grade panels which both stiffen the existing floor and provide uniform support to prevent cracks in the tile above.