A cement board is a mixture of cement and reinforcing fibers formed into sheets, of varying thickness that are normally used as a tile backing board. Cement board can be pinned 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 outward of buildings as a base for exterior plaster 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 board has better long-term performance than paper-faced gypsum core products because it will not decay or physically break down in the continued presence of dampness or leaks. Also cement board provides a stronger bond and support with tiles than typical gypsum board. Cement board is not waterproof. It absorbs humidity as well, but it has excellent drying properties.