Floor Tile Backer Board Or Subfloor

If needed cut the backerboard to fit in small spaces or around obstructions.

Floor tile backer board or subfloor.

Add more mortar as necessary to fill sunken areas in. Cement based backer board. Its made from cement and sand and is reinforced by fiberglass mats on both sides so it s impervious to water. Plan so the joints in the backerboard won t line up with the joints in the subfloor.

To achieve the ideal flat surface most contractors rely on the backer board cement backer board is a thin layer of concrete designed to be setting surface upon which tile can be installed. Do a dry run and lay the backerboard down to fully cover the area you plan to tile. Now largely regarded as the very best underlayment for ceramic tile in any application floors walls and countertops cement based backer board goes by many names. The backer board is then secured with screws to the subfloor beneath.

If the subfloor doesn t have enough stability you can usually but not always remedy the situation by installing cement backer board also called cementboard. Cement board is the most durable trouble free tile backer for tub surrounds showers floors and all other wet areas. The backer board comes in different sizes and you will pick the right one depending on the type of floor you are installing. Floor tiles should be installed over smooth flat surfaces.

Leave a 1 4 inch gap between the edges of the backer board and the walls to allow for subfloor expansion and contraction. The thickness of the subfloor including the cement backer board should be a minimum of 1 1 8 thick so if you use 1 2 backer board you would need at least 5 8 plywood. Spread the mortar to about 3 16 thickness. 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.

Also if your subfloor runs east to west lay your backer boards in the opposite direction north to south. Using a notched trowel apply a leveling bed of thinset mortar over the subfloor and embed the backer board sheets into the adhesive. Lay the backer board according to the manufacturer s instructions. Good luck with your project.

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. Second the strength of wood boards isn t always consistent. The backerboard should completely cover the subfloor joints. It is generically called cement board or backer board or it can also be referred to by one of the common brand names such as densshield hardiebacker and wonderboard.

So the answer is yes you would need to install a plywood subfloor under the cement backer board before applying the tile.