Backer Board

Backer board creates a flat, stable, moisture-resistant base for tile and stone. Installed over wood subfloors or wall framing, it bridges movement, improves thinset adhesion, and helps prevent cracked grout and tile. This moisture-tough underlayment is a smart upgrade for bathrooms, kitchens, laundry rooms, and showers, where water and humidity challenge traditional substrates. By choosing the right tile backer board, you increase durability, accuracy, and long-term performance of your flooring project, whether you’re a contractor aiming for consistent results or a DIYer planning a weekend bathroom remodel.

Common options include cement board and fiber-cement board, valued for rigidity, mold resistance, and fire performance; foam backer board, prized for light weight and built-in waterproofing; and glass-mat gypsum boards for certain wall applications. Typical thicknesses are 1/4 inch for floors and 1/2 inch for walls. Use cement or foam boards for tile underlayment on floors; pair with liquid or sheet waterproofing in wet zones for a continuous waterproof tile substrate. Look for boards that carry manufacturer approvals for heated floors, shower pans, and large-format tile where added stiffness matters.

For a clean installation: bed floor panels in thinset mortar, fasten with corrosion-resistant backer board screws 8 inches on center, and stagger joints. Leave 1/8-inch gaps at panel edges and around room perimeters. Tape seams with alkali-resistant mesh and skim with thinset. Seal penetrations and transitions, then apply a waterproofing membrane in showers or other wet areas. Cut boards by scoring and snapping to limit dust, or use a carbide or diamond blade with proper PPE. Thoughtful selection and careful installation of flooring backer board deliver a smooth, long-lasting tile underlayment that stands up to daily use.