Installing a tile backsplash can add style and visual interest to your kitchen. While tile is an attractive and durable material, proper installation is crucial for it to withstand daily use and moisture over time. Many homeowners wonder if they need to install backerboard behind their tile backsplash or if they can simply stick the tiles to the existing wall. There are a few factors to consider when determining if backerboard is recommended for your particular tile backsplash project.
What is Backerboard?
Backerboard, also known as cement board, is a rigid tile underlayment material made from Portland cement. It is available in sheets, typically 1/4 or 1/2 inch thick. Backerboard provides a strong, stable surface for installing tile in wet areas like kitchens and bathrooms.
The advantages of using backerboard include:
- Prevents moisture damage: Backerboard is waterproof and moisture-resistant, preventing water from seeping through to the framing and drywall behind the tile. This helps prevent rot, mold growth and damage over time.
- Supports weight: Backerboard is engineered to be dense and sturdy. It provides a solid foundation to support the weight of tile and grout without sagging or deforming.
- Non-organic: Unlike wood or drywall which can deteriorate when exposed to moisture over time, backerboard will not break down or warp.
- Adds structure: Backerboard helps strengthen walls and provides a rigid surface for a high quality tile installation. The tile is less likely to crack or loosen over time.
When is Backerboard Required?
Many building codes and tile manufacturer instructions specify backerboard as the recommended underlayment for tile installations. However, the specific requirements can vary depending on the:
- Type of tile: Natural stone tiles like marble, granite or travertine often require backerboard due to their weight. Ceramic and porcelain tiles are lighter but may still need the additional support depending on size and application area.
- Tile size: Larger format tiles with longer edges create more leverage and are prone to cracking or popping off without the proper underlayment. Backerboard is typically recommended for tiles larger than 4 inches.
- Wall material: Existing drywall or plaster walls do not provide enough stability for most tile installations. The one exception is when installing a basic backsplash with very small mosaic tiles.
- Installation location: Backsplashes, tub/shower surrounds, and countertops in bathrooms and kitchens require water-resistant backerboard due to direct water exposure.
- Substrate condition: Backerboard is advised if the wall surface is damaged, uneven or has existing mold or moisture problems. The rigid backerboard will provide a flat, stable layer for tile rather than a compromised wall.
If you are tiling over drywall, it is highly recommended to install backerboard unless you have a very lightweight mosaic tile backsplash. The backerboard creates a permanent water barrier to protect the drywall behind it.
What are the Backerboard Options?
There are a few different types of backerboard designed for tile installations:
- Cement board: The most common type, cement board is made of reinforced concrete sandwiched between fiberglass mesh. Brands like HardieBacker or Durock are available in sheets at home improvement stores.
- Fiber-cement board: This backerboard contains cement mixed with wood pulp fiber. James Hardie’s HardieBacker 500 is a popular fiber-cement option.
- Glass-mat backerboard: This water-resistant backerboard features fiberglass mesh embedded in a gypsum or cement core. Brands like DensShield and FiberBacker feature proprietary waterproof coatings.
- Fibre-reinforced gypsum backer: Gypsum reinforced with fiberglass strands provides fire resistance and water resistance. Georgia-Pacific’s DensArmor Plus is a commonly used example.
- Coated polymer-modified panels: These cementitious panels have acrylic or SB latex coatings to create an enhanced vapor barrier and waterproofing. Examples include USG’s Fiberock Aqua-Tough and National Gypsum’s Permabase.
All of these backerboard types provide adequate support for tile backsplashes. Cement board is the most widely available and cost effective option for most homeowners.
How is Backerboard Installed?
Installing backerboard involves several steps, but it is a relatively straightforward DIY project if you are comfortable with basic tools. Here is an overview:
- Prepare the surface: Remove existing wall coverings down to the studs or masonry wall surface. Clean off any loose material or debris.
- Mark the studs: Locate the wood or metal studs using a stud finder. Mark their locations with painters tape.
- Cut the backerboard: Measure and cut the cement board to size using a utility knife and straight edge. Cut holes for any outlets.
- Fasten with screws: Secure the backerboard sheets to the studs using backerboard screws, spacing them 8 inches apart across the studs.
- Fill seams: Fill the seams between backerboard sheets with fiberglass mesh tape and thinset mortar to create a waterproof barrier.
- Seal penetrations: Seal any gaps around fixtures or penetrations with silicone caulk.
- Skim coat: Apply a final thin skim coat layer of mortar over the entire surface to smooth it out before tiling.
Always follow manufacturer instructions for proper fastening and spacing of specific backerboard products during installation.
What About Using a Membrane or Paint-On Barrier?
Some homeowners consider using a waterproofing membrane or liquid water barrier coating rather than backerboard behind their tile. Products like RedGard and Custom’s MBP offer paint-on waterproofing layers. Other sheet membranes like Schluter Kerdi can be installed to waterproof existing walls.
While these products serve as moisture barriers, they have some disadvantages compared to rigid backerboard:
- They don’t provide the same structural support or rigidity for the weight of tile.
- Soft or uneven wall surfaces can still telegraph through.
- TIle may be more prone to cracking if the substrate shifts or settles.
- They don’t prevent underlying drywall from potential moisture damage.
For most tile installations, backerboard remains the recommended underlayment over just a water barrier layer according to building codes and tile manufacturers. However, for some very lightweight applications or smooth, stable walls, a waterproofing paint or membrane may be sufficient according to some tile setters.
If considering just a water barrier rather than backerboard, consult the tile manufacturer specifications and check local building codes for approval on your specific application. An experienced tile setter can also advise if it may be acceptable for your particular project.
Conclusion
Installing backerboard behind tile backsplashes provides important benefits beyond just waterproofing. The rigid support prevents cracking and damage over time while strengthening the wall. For most applications, building codes and tile makers recommend using proper water-resistant backerboard rather than just applying a water barrier layer. Cement board offers the most economical and readily available backerboard option. With proper preparation and installation, backerboard creates a durable, lasting foundation for a beautiful tile backsplash. Carefully follow manufacturer and code guidelines to determine if backerboard is required or recommended for your upcoming tiling project.
Frequently Asked Questions About Backerboard for Tile Backsplashes
Q: Can I install tile directly on drywall?
A: Installing tile directly on drywall is generally not recommended, especially for backsplashes which are exposed to moisture. Drywall is prone to water damage and lacks the rigid support needed for tile. Backerboard or another suitable underlayment should be applied over drywall first.
Q: What thickness of backerboard should I use?
A: For wall tile like backsplashes, 1/4 inch or 1/2 inch backerboard is commonly used. Thicker 3/4 inch boards may be recommended for floors or counters supporting very heavy tile. Always verify the backerboard thickness recommended by your tile manufacturer.
Q: Should backerboard seams be taped?
A: Yes, sealing the seams between backerboard sheets with joint tape and thinset creates a waterproof barrier and prevents moisture getting behind the panels. Mesh tape embedded in mortar is recommended.
Q: Can I use drywall screws to install backerboard?
A: No, backerboard requires specialized backerboard or cement board screws. They have thicker shafts and wide heads to properly fasten into the cementitious material without stripping.
Q: Is redgard as good as backerboard?
A: Redgard and similar liquid membranes provide waterproofing but lack the rigidity and structure of backerboard. For wall stability and preventing tile cracking, backerboard is generally the recommended underlayment according to building codes and manufacturers.
Q: Can I tile directly on plaster walls?
A: Old plaster can be prone to cracking and crumbling when tile is applied directly. It is advised to install backerboard over plaster to create a more stable subsurface for the tile. This helps prevent loose or cracked tiles over time.
Q: Can I put backerboard over drywall in a bathroom?
A: Yes, installing backerboard over existing drywall is recommended in wet areas like bathrooms. The backerboard creates a waterproof barrier to prevent moisture from damaging the drywall behind the tile. Follow proper sealing procedures.
Q: What is the best backerboard for kitchen backsplash?
A: For kitchen backsplashes, most tile setters recommend traditional cement backerboard panels such as those made by HardieBacker or Durock. Cement boards provide an affordable, readily available option suitable for most backsplash tile types.
Q: Is DensShield or HardieBacker better?
A: Both DensShield and HardieBacker are quality backerboard brands that provide moisture resistance and support for tile jobs. DensShield is lighter and made of treated gypsum, while HardieBacker is traditional sturdy cement board. Either provides good performance as a tile substrate.
Q: How do I waterproof backerboard?
A: To waterproof backerboard, use mesh tape and thinset mortar to seal all seams and gaps. Coat screw heads with thinset. Seal penetrations with silicone caulk. Then skim coat the entire surface with a final thin layer of thinset mortar to fully waterproof the backerboard.