Before we go any farther on how to install cement board i am going to talk about a very common mistake most people make.
Installing cement board on concrete floors.
The 1 mistake most people make when installing cement board.
These convenient panels of cementitious board provide an instant flat hard surface that bonds with the thin set adhesives or mortars used to install tile.
Precut and fit all the cement board and then lift all of the cement boards out.
Yet this application does make sense since concrete is heavy solid and is typically thought of as an unbending uncompromising material.
Ceramic and porcelain tile are so frequently installed at or above grade level on a cement board underlayment or directly on plywood that it almost seems novel to install tile directly on concrete.
For ceramic tile floors the cement board usually rests on a plywood subfloor minimum 5 8 inch thick exterior grade plywood or osb if new ceramic tile is being laid on an existing floor the cement board can usually be laid right over the existing floor finish provided it is in good shape and the extra floor thickness is not a problem.
Cement board is a type of underlayment that is now standard for most tile installations but particularly for floor tile.
Placing cement boards over the concrete subfloor is an excellent way to create a solid and smooth subfloor.
Installing tile directly on concrete.
However a homeowner may need to raise the floor slightly before installing tile and lack the experience or time to install a mortar bed.
In fact i think it would create more problems than it would solve.
It is very important to first spread thin set on the floor before placing the cement board to the floor.
The primary benefit of cement board is that it doesn t break down or expand or warp if it gets wet.
Concrete floors should be mechanically abraded by some means.
The best way to address any inferior concrete surface in preparing it for a tile installation is to use a direct approach.
Cement board also provides an additional layer over a plywood or particleboard subfloor adding stiffness to the tile.
Installing a cement backerboard is crucial when you want a waterproof tile floor that lasts for years without cracking.
Cement backerboard is a thin layer of concrete with fiberglass mesh on both sides.
This is a distinct advantage over plywood and drywall.
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.
I know it seems like a smooth surface and it seems like it may fix some of the issues with the concrete floor but don t do it.
Installing cement board over a concrete subfloor.
If you have a concrete subfloor then you should not be contemplating installing cement board over it.
The various brands of cement board such as hardiebacker durock denshield and wonderboard have become a standard tile backer material for nearly all ceramic porcelain and stone tiles for floor wall and countertop applications.
No sir installing cement boards over concrete just isn t a very practical idea.
