Introduction
Installing tile in your home can provide a beautiful, durable, and easy-to-clean surface, but proper prep work is essential for success. One of the most important steps when tiling a wall or floor is to install a proper tile backer board as your underlayment.
Tile backer board creates a water-resistant, stable surface that won’t easily crack or warp under the weight of the tile. It’s a must-have for most tile installations. But with so many options on the market, it can be confusing to choose the right backer board for your specific project.
In this guide, we’ll walk through everything you need to know before buying tile backer board, including:
What is Tile Backer Board?
- The role of backer board in tile installations
- Differences from drywall as an underlayment
- Types of backer board materials
Benefits of Using Tile Backer Board
- Provides a waterproof surface
- Creates a durable, rigid base
- Resists mold and mildew
- Allows for thinset mortar application
Choosing the Right Tile Backer Board
- Cement board vs. fiber-cement board
- Underlayment panels vs. mats
- Areas appropriate for each type of board
Working with Tile Backer Board
- Best practices for installation
- Cutting and scoring techniques
- Sealing and waterproofing methods
- Transitioning between materials
Tile Backer Board Costs
- Material prices per sheet
- Added costs for accessories and tools
- Estimating how much you need
By the end of this guide, you’ll be well-equipped to choose and install the right tile backer board for your tiling project. Let’s dive in!
What is Tile Backer Board?
Before we get into the specifics of selecting a backer board, let’s start with a quick overview of what tile backer board is and its role in tile installations.
The Purpose of Tile Backer Board
Tile backer board, also known by its genericized trademark name Cement board, is a rigid panel used as an underlayment for tile installations. It’s made of cement, sand, and cellulose fibers that have been pressed into sheets.
Backer board is installed on surfaces like walls, floors, countertops, and even ceilings before laying the tile. It provides a smooth, durable, and water-resistant foundation for the tile.
The benefit of tile backer board over traditional drywall underlayment is that it’s not compromised by moisture. Drywall is prone to mold growth and deterioration when exposed to repeated moisture. Backer board resists this damage.
Tile backer boards also provide a perfectly rigid surface that won’t crack or warp under pressure, flex with movement, or sag over time. This helps prevent cracked grout and tile popped loose from the substrate.
Key Differences from Drywall
While tile backer board may look similar to drywall at first glance, there are some important differences:
- Composition: Backer board is made from a mix of cement, aggregates, and cellulose fibers. Drywall is made from gypsum pressed between paper facers.
- Rigidity: The cementitious nature of backer board makes it highly rigid and dimensionally stable. Drywall can sag over time.
- Water resistance: Tile backer board is waterproof and moisture-resistant. Drywall will deteriorate when exposed to moisture.
- Load-bearing: Backer board is stronger and better at bearing weight, such as tile, without cracking.
- Thickness: Backer board comes in 1/4-inch to 1/2-inch thicknesses. Drywall is usually 1/2-inch to 5/8-inch thick.
- Finishing: Backer board has a naturally rough surface and requires skim coating before applying tile. Drywall comes pre-finished.
So in summary, backer board is the clear choice whenever you need an underlayment for tile exposed to moisture.
Types of Backer Board Materials
There are two main categories of backer board product:
Cement Board: The most common and traditional type of backer board is made of cement and aggregate pressed between fiberglass mesh. Major brands include HardieBacker®, Durock®, WonderBoard®, and FibaFuse®.
Fiber-Cement Board: Fiber-cement backer boards feature cellulose fiber reinforcement in the cement mix. Popular brands include HardieBacker® and FiberBoard Underlayment.
Within these two categories, backer boards come in a few different forms:
- Underlayment panels: Large format sheets, typically 3 x 5 feet. These need to be cut to size.
- Mats: Boards adhered to a fiberglass mat for reinforcing joints. Mats have broken scores for tearing the pieces apart.
- Boards: Shorter boards (1 x 3 feet) with tongue-and-groove or square edges. Some brands focus on boards rather than panels.
We’ll go into more detail on the different product formats and brands later in this article.
Benefits of Using Tile Backer Board
Now that you know the basics of what tile backer boards are, let’s look at the key benefits they provide for tile installations:
Water and Moisture Resistance
The number one benefit of backer board is its waterproof properties. The cementitious material is non-porous and does not absorb or allow water to pass through.
This water resistance prevents moisture from penetrating into the substrate material behind the backer board. It provides a moisture barrier that protects wood and drywall layers from water damage. This is extremely important for wet areas like bathrooms and showers.
Tile backer board’s waterproofing also prevents the growth of mold and mildew. When replacing shower enclosures, backer board helps create a healthy underlayment free of previous biological contaminants.
A Rigid, Stable Base for Tile
Quality backer board offers unmatched rigidity and dimensional stability compared to alternatives like drywall. The cement-based boards will not compress, shrink, or swell under pressure.
This provides a perfectly flat and true foundation on which to install tile without risk of cracking grout or loosening tiles later on. Minor imperfections can be smoothed with skim coating.
The rigidity also allows for a thinner product, since it requires less thickness to bear loads without flexing. Many backer boards are available in 1/4-inch thicknesses.
Allows Thinset Mortar Application
Quality backer boards have surfaces engineered to bond well with thinset tile mortar. This allows applying a layer of thinset directly onto the backer board before setting tile.
The thinset fills in the natural texture of the backer board surface to create a mechanical bond as it hardens. This is a more durable connection than simply using mastic.
Backer board’s stiffness also prevents the substrate from sagging or warping under the weight of the tile and thinset. The result is strong, long-lasting adhesion between your tiles and underlayment.
Resists Cracking and Deterioration
Underlayments like drywall can develop cracks and crumble around the edges when repeatedly exposed to moisture. Tile backer board’s fibers and composition reinforce it against deterioration.
The cement and cellulose fibers provide tensile strength. The fiberglass mesh commonly layered in the core prevents crack propagation.
This resistance to cracking means tiles stay firmly adhered to the backer board. You don’t have to worry about damage to the underlayment over time after your tile is installed.
Choosing the Right Tile Backer Board
Now that you understand the benefits of tile backer board, let’s explore how to select the right product for your specific tiling project.
Key factors that differentiate backer board products include:
- Material composition: Cement vs. fiber-cement
- Format: Underlayment panels vs. mats vs. boards
- Areas for use: Floors, walls, bathrooms, etc.
Considering these factors will help you pick the optimal backer board for each installation location.
Cement Board vs. Fiber-Cement Board
The two main types of backer board materials provide slightly different properties:
Cement Board
- Made of Portland cement, sand, and fiberglass mesh reinforcement
- Provides compressive and flexural strength
- Withstands prolonged water exposure
- Common brands include HardieBacker®, Durock®, WonderBoard®
Fiber-Cement Board
- Uses cellulose fiber reinforcement instead of fiberglass
- Excellent tensile and impact strength
- Super moisture and mold resistant
- Brands like HardieBacker® and FiberBoard Underlayment
In general, fiber-cement boards provide enhanced durability, especially resisting cracks if the underlying structure shifts. They’re lighter weight as well.
But cement boards offer greater versatility and are still highly water-resistant. They can be used in interior and exterior applications.
Whichever material you choose, look for boards that carry ANSI A118.9 certification for quality assurance.
Panels vs. Mats vs. Boards
As mentioned previously, tile backer boards come in a variety of formats:
Panels: Large format sheets sized 3×5 feet typically. You cut panels to size.
Mats: Boards adhered to a fiberglass mat. Just tear apart pieces along perforated scores.
Boards: Short boards (1×2 or 1×3 feet) with square or tongue-and-groove edges.
Here are some pros and cons to consider:
Panels
- Provide greatest flexibility in sizing
- Allow creating seamless spans in larger areas
- Require own cutting to size
Mats
- Super easy installation with perforated pieces
- Mesh improves joint strength
- Limited to mat size for continuous spans
Boards
- Offer rigid support and easy installation
- Good for small areas like backsplashes
- Seams required for broader coverage
In general, panels are the most adaptable format and easiest to work with. But mats can be a quicker solution for small areas, and boards provide a rigid pre-cut option.
Choosing Areas of Use
Considering your project’s specific location will help determine the ideal panel composition and format:
- Floors: Cement board panels allow seamless spans; boards work for smaller areas.
- Walls: Either fiber-cement or cement boards panels provide flexibility. Mats useful for backsplashes.
- Wet Areas: Fiber-cement panels or boards provide max moisture resistance.
- Ceilings: Cement board panels necessary to support tile weight.
- Countertops: Cement boards or mats create stable layer before tiling.
- Exteriors: Cement board panels hold up to outdoor exposure.
Always check manufacturer guidelines for each product’s intended applications. Some have limits or requirements for exterior use, for instance. Pick products designed for your project’s location.
Working With Tile Backer Board
Once you’ve selected the ideal tile backer board for your project, the next step is proper installation. Here are some tips on working with backer boards:
Best Practices for Installation
- Follow all manufacturer’s instructions for boards to qualify for any warranties.
- Acclimate panels to room temp before installation.
- Use concrete, ceramic tile, or modified thinset mortar to adhere boards.
- Fasten panels with backer board screws, not drywall screws.
- Space screws 6-8 inches apart across fields and edges.
- Keep board seams evenly spaced and staggered.
- Tape and “mud” seams with joint compound for smoother finish.
Taking steps like using the right mortar and fasteners ensures your backer boards are securely and permanently installed.
Techniques for Cutting and Scoring
Tile backer board requires specialty cutting tools and techniques:
- Cutting board: Use a utility knife and straightedge. Score deeply and snap board face down.
- Cutouts: Drill pilot holes and use a jigsaw with carbide blade, or use a router.
- Edges: Cut outs with notch trowel or rasp tool to fit outlets and fixtures.
- Holes: Make plumbing and screw holes with a carbide-grit hole saw.
Go slowly when scoring and cut from the backside to avoid crumbling cementitious face coatings. Take proper safety precautions.
Sealing and Waterproofing Methods
For wet areas, waterproofing is crucial:
- Seal seams and fastener indentations with mesh tape and unmodified thinset.
- Use 100% silicone or urethane caulk for gaps at walls or fixtures.
- Paint, roll, or trowel on liquid waterproofing membrane after installation.
- Use waterproofing sheets like Schluter®-Kerdi for total coverage.
Waterproofing protects moisture-sensitive framing and prevents mildew growth behind walls.
Transitioning to Other Surfaces
When joining backer board to flanges like bathtubs:
- Remove drywall facing down to studs/framing to support edges.
- Screw in backer board flush with flange height.
- Fill gaps with thinset mortar for ramping.
- Caulk gaps with flexible sealant.
This ensures proper load transfer and waterproof transitions.
Following best practices for installing and finishing tile backer board will result in a beautifully tiled surface that lasts.
Tile Backer Board Costs
As you budget for your tiling project, here is what you need to know about the costs of purchasing and installing backer board:
Backer Board Material Prices
Tile backer board costs $8 to $30 per 32 square foot sheet on average based on:
- Cement board vs. fiber cement: Fiber-cement boards cost more.
- Panel vs. mat vs. board: Boards cost more per square foot than panels. Mats are least expensive.
- Thickness: 1/4-inch panels are cheapest at $8-15 per sheet; 1/2-inch runs $15-30.
- Brand: Premium brands can be 50% more costly than generic.
Always compare per square foot prices when considering different board sizes and thicknesses.
Added Costs to Install
Beyond the raw board materials, factor in expenses for:
- Thinset mortar: $5 to $15 per 50 lb. bag.
- Backer board screws: $15 per 100 pack.
- Joint tape and compound: Around $15 total.
- Waterproofing: $40+ per gallon of liquid membrane or roll of sheet membrane.
- Tools: Snap cutter, carbide blades, hole saws, etc. if you don’t have them.
Consider if professional installation labor fits your budget as well.
Estimating How Much You Need
Measure the square footage of your installation areas and purchase boards with 10-15% extra area for cutting waste and seams.
Most backer board brands provide square foot calculators on their websites to help estimate needs for specific rooms or projects.
Factor type of application too – walls require vertical seams while floors need sturdy seam strength. Get product recommendations from tile stores for your project.
With some planning and budgeting, you can find affordable backer board solutions to create a lasting underlayment for beautiful tile.
Conclusion
Installing tile backer board is an essential part of any tile installation process. Selecting the right backer board ensures your tile project gets started on the right foot with a solid, water-resistant substrate.
There are many high-quality backer board options to choose from, ranging from cement to fiber-cement boards, panels to mats, and products intended for floors, walls, wet areas, and more. Take stock of your project’s specific needs when deciding which will work best.
And don’t forget appropriate accessories like tape, thinset, and fasteners to complete the installation following manufacturer guidelines. Investing in the right backer board makes a world of difference for achieving stunning tile results.
With the information in this guide, you now have all the necessary knowledge to pick out and install the perfect tile backer board for your upcoming tiling project. Feel free to refer back to the tips and recommendations as you map out your materials and process.