What is Cement Board? Uses of Cement board

What is Cement board?

A cement board is a combination of cement and reinforcing fibers formed into 4 foot by 8 foot sheets (or 3 foot by 5 foot sheets), 1/4 to 1/2 inch thick that are typically used as a tile backing board.

Cement board can be nailed or screwed to wood or steel studs to create a substrate for vertical tile and attached horizontally to plywood for tile floors, kitchen counters and backsplashes. It can be used on the exterior of buildings as a base for exterior plaster (stucco) systems and sometimes as the finish system itself.

Cement board adds impact resistance and strength to the wall surface as compared to water resistant gypsum boards. Cement board is also fabricated in thin sheets with polymer modified cements to allow bending for curved surfaces.


Cement boards are mainly cement bonded particle boards and cement fibre. Cement bonded particle boards have treated wood flakes as reinforcement, whereas in cement fibre boards have cellulose fibre, which is a plant extract as reinforcement.

Cement acts as binder in both the cases. The fire resistance properties of cement bonded blue particle boards and cement fiber boards are the same. In terms of load-bearing capacity, cement-bonded particle boards have higher capacity than cement fibre boards.

Cement particle boards can be manufactured from 6 mm to 40 mm thickness making it ideally suitable for high load bearing applications. These boards are made of a homogeneous mixture and hence are formed as single layer for any thickness.

What do you use cement board for?

As a tile backing board, cement board has better long-term performance than paper-faced gypsum core products because it will not mildew or physically break down in the continued presence of moisture or leaks. Cement board is not actually waterproof, but it is highly resistant to absorbing moisture and has excellent drying properties.
In areas continually exposed to water spray (i.e. showers) a waterproofing barrier is usually recommended behind the boards or as a trowel-applied product to the face of the boards behind the finish system.

How do you install cement board?

Cement board is hung with corrosion resistant screws or ring-shank nails. Cement board siding has very little movement under thermal stress, but the boards are usually installed with a slight gap at joints in shower pans, bathtubs, and each other.

These joints are then filled with silicone sealant or the manufacturer's taping compounds before applying a finish. The filled joints are taped like conventional gypsum board, but with fiberglass tapes that provide additional water resistance. Combined with a water impermeable finish, cement board is a stable, durable backing board.

Cement Board vs. Drywall

To understand cement backer board, you should first look at its cousin--drywall. For years, interior walls were finished with lath (wood strips) and plaster laid over the studs. Plasterers used hundreds of pounds of plaster, trowel by laborious trowel.

Then someone got the brilliant idea of pressing all of that plaster, plus the structural qualities of the lath, ahead of time in a factory--in the form of sheets of drywall.

This is the basic idea behind cement backer board. Instead of laying beds of mortar on the job site, or using inferior backing boards such as greenboard, you can simply screw in these pre-formed and already-set sheets of concrete board. Pretty neat.