Backing board, or backer board, is a type of material commonly used in the construction industry. The backing board provides a substrate for installing tile, stone and other materials to walls and floors. There are various types of backing board materials manufactured to meet the specifications of different applications.
Traditionally, when installing tile, tile setters would install wire lathe and use mortar to float out areas to provide a substrate for adhering tile, stone and other materials. This was a time-consuming and labor-intensive process. Backing board simplifies this process because the sheets are cut to size then installed using applicable corrosion-resistant screws to secure them to the studs. This not only reduces the amount of time to install a suitable substrate, it also reduces the overall cost of the project.
The most popular type of backing board is called cement backer board. This water- and mold-resistant material has a life span of as long as 50 years. The cement backing board is manufactured by compressing sheets of cement pressed between two sheets of fiberglass. The sheets are manufactured in various lengths, widths and thicknesses. Cement backing board sheets are cut by scoring the surface with a utility knife and snapping it along the scored line.
Another type of backing board is green board. This water-resistant material was once a popular substrate for surrounding bathtubs and showers, but it did not hold up well in high-moisture areas. It is now limited to areas outside of the tub, such as bathroom walls, backsplashes and porch ceilings. A form of drywall, the green board cuts easily by scoring it with a utility knife and then snapping it along the scored line.
Cement backing board is suitable for walls and flooring applications. Green board is limited for use on wall applications only. Both types of backing board material install using corrosion-resistant screws that attach the board to the wall studs or floor. After installation, the joints between the sheets are taped using an applicable joint compound and tape material suitable for the intended application. This not only provides a smooth area between the sheets, it prevents moisture from entering the wall cavity through the seams.