Do I Need A Sub Floor For Cement Board

I need to match the height of the existing tile in the bathroom.

Do i need a sub floor for cement board.

Make sure the joists are wide enough for the span and spaced on 16 centers to provide a sturdy floor with no bounce. Embed the cement board in latex modified thin set mortar the main reason for using thin set between the cement board and the subfloor isn t as much for bonding as it is for even void free cement board support throughout the floor. It strengthens the floor removes bounce and gives the tile a. 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 backer board is more dimensionally stable than plywood and forms a better bond with the thin set adhesive used to glue the tile down. They skipped putting down the thin set under the cement board even though the installation instruction specify that it is required. This is a distinct advantage over plywood and drywall. If it is a planked floor then y.

And then once the cement board is down and it s screwed in do i have to put some type of mesh tape to put the boards together and then mortar the tape. If it is vinyl tile glued over a concrete slab you can clean the tile and adhere the tile directly to the vinyl. The primary benefit of cement board is that it doesn t break down or expand or warp if it gets wet. Cement board also provides an additional layer over a plywood or particleboard subfloor adding stiffness to the tile.

Precut and fit all the cement board and then lift all of the cement boards out. I plan on thinsetting and screwing cement board to the subfloor then redgard then thin set and tile. So you would screw that down to. Apply a supporting bed of mortar or modified thinset to subfloor using a 1 4 square notched trowel.

Here s the right way to attach cement backer board to a plywood subfloor. The plywood subfloor should be at least 5 8 thick on 16 centers 3 4 preferred and securely attached to the joists preferably with screws. Cement board a sheet of lightweight concrete and fiberglass mesh should be laid over top of the subfloor for any tile project. It depends on the sub surface if it is a concrete slab then no but if it is a plywood decking yes.

This means that tile applied to cement backer board resists cracking and popping loose better than tile applied to a plywood subfloor alone. Would this calculation get me to the right height compressed thin set on top of sub floor 1 8 cement board 1 2 compressed thin set on top of cement board 1 8.