What Is Backer Board?
Before installing tile, you need a flat, stable substrate that’s suitable for the application. Backer board is a panel product commonly installed behind or beneath tile to create a durable surface for installation.
Depending on the product, backer board may be made from cement, fiber cement, gypsum-based materials or foam. Some types are designed to resist moisture while others can be incorporated into waterproof tile assemblies.
Backer board also helps provide a stable surface that reduces movement beneath the tile, which can help reduce the risk of cracked tile and grout.
Uses of Tile Backer Board
Backer board can be used for a variety of tile projects. The appropriate type depends on the location, moisture exposure and manufacturer specifications.
Backer board is commonly installed beneath tile flooring in kitchens, bathrooms, laundry rooms and entryways. Cement and fiber cement backer boards provide a stable tile substrate and are resistant to damage from moisture.
Approved backer boards can also be used behind tile on shower walls, backsplashes and tub surrounds. In wet areas such as showers, the entire assembly must provide appropriate water management. Some backer boards require a separate waterproofing membrane while certain foam and other specialty boards can be part of a waterproof system when seams, fasteners and penetrations are sealed according to the manufacturer’s instructions.
Some backer boards are also suitable for tile countertops and fireplace surrounds. For fireplace applications, make sure the specific product and installation method are approved for the temperatures and clearances required by the fireplace manufacturer. For exterior tile projects, use only backer boards specifically approved by the manufacturer for exterior applications.
Tile Backer Board Types
Common tile backer board types include cement board, fiber cement board, gypsum-based tile backer and foam backer board. Each has different characteristics and installation requirements, so check the manufacturer’s instructions before choosing a product.
Cement Backer Board
Cement backer board is typically made from cement and aggregate and may include reinforcing mesh. It creates a strong, durable substrate for tile and is commonly used for floors, walls, countertops, tub surrounds and shower applications.
Cement board is water-durable and won’t deteriorate from normal exposure to water, but cement board itself shouldn’t automatically be considered a waterproofing layer. Wet-area installations may require a separate waterproofing membrane or other water-management system.
Cement board is heavier than many other types of tile backer and can be more difficult to cut and handle. Cutting cement-based products can also produce silica-containing dust, so follow the manufacturer’s cutting instructions and recommended safety precautions.
Fiber Cement Backer Board
Fiber cement backer board combines cementitious materials with reinforcing fibers. It provides a strong, dimensionally stable surface for tile and is available for floor and wall applications.
Compared with some traditional cement boards, certain fiber cement products can be lighter or easier to cut and handle. They also resist damage from moisture, making them suitable for many kitchens, bathrooms and other moisture-prone areas.
Product characteristics vary, so check the manufacturer’s specifications for approved applications, waterproofing requirements and installation instructions.
Glass-Mat Gypsum Backer Board
Glass-mat gypsum backer board uses a moisture-resistant gypsum core with fiberglass mats instead of traditional paper facings. Products specifically designed and approved as tile backer can be used in certain wet-area applications according to the manufacturer’s instructions and local building codes.
Glass-mat gypsum tile backer shouldn’t be confused with conventional moisture-resistant drywall, sometimes called greenboard. Standard moisture-resistant gypsum board isn’t intended as a tile substrate in shower or tub wet areas.
Gypsum-based tile backer is typically easier to cut and handle than cement board. However, approved applications vary by product, so always follow the manufacturer’s instructions.
Backer Board Maintenance
Once tile is properly installed, tile backer board is concealed beneath the finished surface and generally doesn’t require routine maintenance or cleaning.
Instead, maintain the finished tile, grout and sealant according to their manufacturers’ recommendations. Periodically inspect showers, tub surrounds and other wet areas for cracked grout, deteriorated sealant or other conditions that could allow water to enter the tile assembly.
If you notice loose tile, persistent moisture or signs of water damage, identify and repair the source of the problem rather than attempting to clean or maintain the backer board itself.