Tile Over Plywood Vs Cement Board

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.

Tile over plywood vs cement board.

Plywood is porous and not designed for use with most of today s latex based thinset mortars. Ok so we had 603 square feet of porcelain tile installed through the first floor of our home. Cement backerboard is designed specifically for this use. 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.

Screws secure the cement board to the wall studs. They were supposed to rip out the plywood put down hardie board and then tile. Cement board also provides an additional layer over a plywood or particleboard subfloor adding stiffness to the tile installation to help prevent cracks. The best argument when determining whether to use plywood or cement board under tile is in the adhesive process.

A number of different types of substrate are used for tile including plywood. But a number of precautions must be taken to ensure a successful installation. The primary benefit of cement board is that it doesn t break down or expand or warp if it gets wet. Even if you use a waterproof underlayment membrane the floor will still be either 1 4 or 1 2 higher than the subfloor plus the thickness of the tile and adhesive.

When the tile is laid on top of a plywood subfloor the plywood will expand over the years. This is a distinct advantage over plywood and drywall. The tile runs from our utility room through the kitchen hall bathroom and foyer. In addition to this tile can not properly adhere to wood the way it does to concrete.

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. For ceramic tile floors the cement board usually rests on a plywood subfloor minimum 5 8 inch thick exterior grade plywood or osb. Tile is laid onto the cement board with thinset mortar or mastic. Then the cement board is installed on top of the plastic sheeting.

While most floor tile these days is installed onto a layer of cement board or similar backerboard it is possible to lay tile directly over plywood. In this highly convenient inexpensive and popular application a moisture barrier of 4 or 6 mil thick plastic is installed directly over the wall studs. As a result the grout lines and the tiles themselves can crack and become damaged.