Installing a kitchen backsplash can greatly improve the look and feel of your kitchen. Many homeowners opt for tile backsplashes, as tile comes in an endless array of styles, shapes, colors, and textures. However, tile requires a solid, water-resistant backing material. While drywall is an economical backing option, it will eventually warp and crumble when exposed to moisture over time. A better alternative is to install backer board, a cement-based panel designed for wet areas like kitchens and bathrooms. But can you install backer board over an existing drywall backsplash? Let’s take a closer look.
What is Backer Board?
Backer board, also known as cement board or tile backer board, is a water-resistant building material made of portland cement and sand reinforced with a fiberglass mesh. The cement makes it moisture resistant while the mesh provides strength and impact resistance.
Backer board is available in sheets, typically 1/4 to 1/2 inch thick. Popular brand names include HardieBacker, Durock, Fiberboard, and WonderBoard. It can be cut with standard hand tools and installed using thinset mortar, screws, and an alkali-resistant fiberglass mesh tape.
Unlike drywall, backer board will not warp, mold, or deteriorate when exposed to water. This makes it an ideal substrate for wet areas in kitchens, bathrooms, laundry rooms, and exterior walls. It provides a solid, durable surface for installing tile, stone, or other backsplash materials in these high-moisture areas.
Pros and Cons of Installing Backer Board Over Drywall
Many homeowners with existing drywall backsplashes may wonder if they can simply install backer board right over the drywall instead of removing the drywall completely. There are a few pros and cons to consider with this approach:
Pros
- Saves time and money: Installing backer board over the drywall eliminates the time-consuming process of tearing out the existing drywall. It also avoids extra costs to haul away and dispose of the drywall.
- Less dust and debris: Leaving the drywall in place creates less dust and debris than demolishing it and starting from scratch. This helps keep the rest of the kitchen cleaner during the installation process.
- No repairs needed: The existing drywall doesn’t need repairs or touch-ups if covered by backer board. Any imperfections are covered up.
Cons
- Increased thickness: Adding 1/4-1/2 inch backer board over 1/2 inch drywall makes the backsplash area 3/4 to 1 inch thicker. This may require adjustments to outlets, cabinets, countertops, and other design elements.
- Weight: Backer board is heavier than drywall and adds more weight to the wall. Older wall framing may need reinforcement to support the extra weight.
- Drywall imperfection telegraphing: Any high or low spots on the underlying drywall may telegraph through the backer board and become visible on the finished tile surface. The wall may need smoothing before backer board installation.
- Moisture issues: Leaving drywall underneath the backer board does not waterproof the wall. Moisture penetrating cracked grout or tile could still reach the drywall and cause swelling or mold.
Steps for Installing Backer Board Over Drywall
If you decide to install backer board over existing drywall, follow these recommended steps:
- Inspect the drywall condition. Verify it is smooth, well-secured to studs, and free of moisture damage or signs of mold.
- Fill any cracks or holes. Use joint compound to fill imperfections for a smooth surface. Avoid skim coating the entire surface.
- Clean and prepare the drywall surface. Wipe away any dust or debris. Apply a drywall primer if needed.
- Mark the stud locations. Use a stud finder to mark all wall studs so backer board can be properly screwed into studs.
- Apply construction adhesive. Spread a layer of adhesive like Liquid Nails over the drywall to help bond it to the backer board.
- Cut backer board to size. Use a utility knife or backer board shears. Dry fit pieces first before applying adhesive.
- Apply adhesive to backer board. Spread more construction adhesive or thinset mortar over the backer board pieces.
- Install backer board. Press firmly into the adhesive. Use backer board screws every 6-8 inches along studs and the perimeter.
- Tape seams. Cover all seams and corners with alkali-resistant fiberglass mesh tape and thinset mortar.
- Prepare for tile. Once the backer board adhesive has cured, the surface is ready for tile installation.
Always follow the specific product manufacturer’s instructions for proper installation of backer board over drywall. Careful prep and installation will help ensure a long lasting, moisture-resistant surface for your new kitchen backsplash.
Frequently Asked Questions
Can I put backer board directly over painted drywall?
Yes, you can install backer board over painted drywall as long as the paint is in good condition. Scuff sand glossy surfaces and clean thoroughly before applying adhesive. Make sure any taped drywall seams are sound.
What type of construction adhesive should I use?
Look for adhesives designed for bonding cement board to surfaces like drywall or wood. Examples include Liquid Nails Fuze It, Loctite Power Grab, or Custom Building Products WonderBoard Liquid Nails Adhesive.
How do I cut cement backer board?
Use a utility knife and straightedge to score and snap cement board to size. For openings like outlets, it’s best to use a jigsaw with a carbide blade or backer board shears. Minimize breathing dust when cutting.
Can I use drywall screws to install backer board over drywall?
No, it’s recommended to use corrosion-resistant backer board screws. They have extra sharp threads to grip into the cement board better than drywall screws. Use 1-1/4″ to 1-5/8″ length screws.
How much thinset mortar do I need to tape the seams?
Mix the thinset slightly looser than for setting tile. About 1/4 cup of powdered thinset per linear foot of seam is sufficient for taping backer board joints. Follow the product directions.
Conclusion
Installing backer board over existing drywall is definitely possible, as long as you take the proper preparation and installation steps. While the process takes a bit more time and effort, it can save on demolition costs and reduce dust and debris in an occupied kitchen space. Just be sure to thoroughly inspect and prep the drywall, use the right combination of adhesives and screw patterns, and properly tape all seams with mesh and thinset mortar. With careful attention to detail, your new tile backsplash over backer board will provide a beautiful, water-resistant surface that lasts for many years.