When installing tile in your home, one of the most important steps is selecting and installing the right backer board. Backer board, also known as cement board, is designed to provide a stable, water-resistant surface for tile installation. Choosing the right backer board is critical, as it will determine the success and longevity of your tiled surface. There are several factors to consider when selecting a backer board, including water resistance, stability, adhesive properties, and ease of installation. In this comprehensive guide, we will examine the most popular backer board options and discuss the advantages and ideal uses of each to help you determine the best choice for your specific tiling project.
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What is Backer Board?
Backer board, or cement board, is a building material made of Portland cement formed into sheets, typically 1/4″ to 1/2″ thick. It is reinforced on both sides with fiberglass mesh. Backer board is designed as an underlayment for wet areas like showers, bathtub surrounds, bathroom floors, kitchen backsplashes, and other areas where tile is being installed. It provides a stable, moisture-resistant surface to adhere tile.
The main benefits of backer board include:
- Water resistant – Does not degrade or deteriorate when exposed to water.
- Stable surface – Dimensionally stable even in wet conditions.
- Prevents cracks – More flexible than drywall and reduces cracked grout/tiles.
- Mold resistant – Cement composition prevents mold or mildew growth.
Backer board typically comes in sheets that are 3 x 5 feet. Many boards feature tapered edges to eliminate high spots when joining multiple sheets. Installation involves cutting boards to size, fastening to studs or substrate with specific backer board screws, and taping/mudding seams. Thinset mortar is then applied over the board and tiles adhered.
Types of Backer Board
There are several types of backer board designed for tile installation. The most common options include:
1. Cement Backer Board
Cement backer board, also known by brand names like Durock, HardieBacker, and PermaBase, is the traditional and most popular backer board for tile installation. It is made of a Portland cement core reinforced on both sides with fiberglass mesh.
Advantages:
- Waterproof and moisture resistant.
- Prevents cracks in tile and grout.
- Stable surface won’t deteriorate or expand.
- Mold and mildew resistant.
Ideal for: Wet rooms like bathrooms, kitchens, laundry rooms, etc. Both wall and floor installations.
2. Fiber Cement Backer Board
Fiber cement backer boards like HardieBacker are very similar to traditional cement backer boards but with slightly different fiber reinforcements.
Advantages:
- Waterproof and stable like traditional cement backer.
- Lighter weight than cement board.
- Easier to cut and install.
Ideal for: Bathrooms, kitchen backsplashes, fireplace surrounds. Mainly walls.
3. Foam Backer Board
Foam backer board is made from extruded polystyrene foam bonded to fiberglass mesh on both sides. It is very lightweight.
Advantages:
- Lightweight and easy to cut and install.
- Insulation value for exterior walls.
- Can be used for curved surfaces.
- Low cost.
Ideal for: Interior wall applications except wet areas. Best for new stud construction vs. remodels.
4. Fiberglass Backer Board
Fiberglass reinforced plastic (FRP) boards provide glass fiber strength in a waterproof backer board.
Advantages:
- Extremely water resistant and vapor retardant.
- Easy to cut, drill, and install.
- Withstands moisture and humidity.
- Lightweight yet strong.
Ideal for: Highly wet areas like tub/shower surrounds, pools, fountains, and steam showers.
How to Choose the Best Backer Board for Your Project
When selecting a backer board, here are some factors to consider for your specific tile installation project:
Location
– For dry interior walls, foam or fiber cement may be sufficient. For shower walls and tub surrounds, use cement, fiber cement, or fiberglass backer.
– For floors, only use cement-based backer boards. Foam and fiberglass boards lack the strength for floor tile.
Water Exposure
– Anywhere tiles will be exposed to water consistently, use cement backer board or fiberglass reinforced plastic boards. Kitchen backsplashes and bathroom floors experience water exposure regularly.
Load Bearing Weight
– If the tiles will support heavy weight, like floor tile, cement board is the strongest option. Fiber cement board also provides substantial load bearing strength.
Construction Method
– For remodeling existing walls, lightweight fiber cement is easier to install over existing surfaces. Foam backer also works well. In new construction, any board type works.
Budget
– Fiber cement and foam backer boards cost slightly less than cement backer options. Fiberglass backer is the most expensive but best for very wet areas.
Ease of Installation
– Fiber cement and foam boards require less cutting and are lighter than traditional cement backer. Fiberglass can be challenging to install.
Best Backer Board by Tile Location
Based on the type of tiling project, here are the best backer board recommendations:
Wall Tile Installation
| Location | Best Backer Board |
| Shower Surrounds | Cement backer board or Fiberglass backer |
| Bathtub Surrounds | Cement backer board |
| Kitchen Backsplashes | Cement backer board |
| Bathroom Walls | Cement backer board |
| Fireplace Surrounds | Fiber cement backer board |
| General Interior Walls | Fiber cement backer board or Foam backer |
Floor Tile Installation
| Location | Best Backer Board |
| Bathroom Floors | Cement backer board |
| Laundry Room Floors | Cement backer board |
| Kitchen Floors | Cement backer board |
| Entryway/Foyer Tile | Cement backer board |
| Basement or Garage Tile | Cement backer board |
As you can see, the cement-based backer boards like Durock, HardieBacker, and other brands are ideal for almost any wall or floor tile installation. Their waterproof properties and strength make them the go-to backer board for tiling contractors and DIYers.
Fiber cement backer board also provides strong performance for many wall applications like fireplace surrounds. Foam backer boards are suitable for dry interior wall tile jobs. And fiberglass backer is great for only the wettest environments like steam showers.
Installation Guide by Backer Board Type
To ensure your backer board is installed properly, follow these best practices based on the type of tile backer board:
Cement Backer Board Installation
Cement backer board can be installed directly onto wood or metal studs or an existing substrate like plywood. Follow these tips:
- Cut boards to fit using a utility knife or backer board shears.
- On walls, install vertically with edges butted, not overlapping.
- Screw to studs every 8 inches across fields and every 4 inches along seams and edges.
- Stagger all joints if double layering.
- Tape and mud all seams and corners.
- Allow mud to fully cure before applying thinset and tile.
Fiber Cement Backer Board Installation
Fiber cement boards install similarly to cement board but require slightly different fasteners:
- Cut with standard circular saw. Can also score and snap off pieces.
- Use galvanized roofing nails or fiber cement screws.
- Space fasteners 8” apart across fields.
- Double up on studs at seams for strength.
- Offset all seams by 16” minimum.
- Tape and mud seams using fiberglass mesh tape.
Foam Backer Board Installation
Foam backer board requires furring strips or another rigid frame:
- Install 1×3 or 1×4 wood or hat channel furring strips 16” on center.
- Place foam board between furring and fasten with 2” roofing nails.
- Can also adhere foam directly to substrate with construction adhesive.
- Tape seams with mesh drywall tape.
- Finish with thinset mortar for strength.
Fiberglass Backer Board Installation
Fiberglass backer board installation requires corrosion resistant fasteners:
- Use galvanized screws or nails to install every 4 inches around perimeter and every 8 inches across fields.
- Double up fasteners at seams.
- Keep seams offset at least one stud cavity.
- Fill gaps with silicone caulk, not joint compound.
- Apply mesh mortar bed for base before tiling.
Always follow the specific manufacturer’s instructions for proper selection of fasteners and installation method when installing any type of backer board.
Tiling Over Existing Surfaces
In renovation or remodeling projects, you may need to install tile over an existing surface other than drywall. Here are some best practices for tiling over:
Plywood
- Ensure at least 5/8” exterior grade plywood.
- Fasten with 2” deck screws every 6”.
- Fill seams with silicone caulk.
- Install cement backer board over top.
OSB
- Seal face and edges with waterproof membrane.
- Fasten with adhesives and 2” deck screws.
- Fill gaps with flexible sealant.
- Install cement backer board on top.
Existing Tile
- Score old grout lines to roughen surface.
- Use epoxy mortar to set new cement board.
- Fasten with screw/washer combo 4” apart.
- Fill countersunk screws with mortar.
Vinyl Flooring
- Remove vinyl floor down to bare substrate.
- Make sure hardboard underlayment is securely fastened.
- Fill any joints with floor leveler.
- Install cement backer board with construction adhesive and screws.
Laminates
- Completely remove laminate down to bare substrate.
- Fill any voids with floor leveler.
- Fasten cement backer using adhesive and backer board screws.
Preparing Backer Board for Tile
Once your backer board is installed, you need to properly prepare it before laying the tile:
- Cure times – Let mortar cure fully between steps. This prevents cracks.
- Moisture test – Test for proper moisture levels before tiling.
- Surface flats – Sand any high spots. Install backer board wedges in low spots.
- Fill holes – Fill any gaps, joints, or countersunk screws.
- Prime surface – Prime with manufacturer approved sealer.
These steps prevent uneven tile and grout cracking by creating a flat, smooth, and stable surface for the tile thinset mortar to adhere to.
Tips for Achieving Best Results
Follow these top tips to ensure your backer board installation results in a beautiful tiled surface:
- Select the right backer board for the specific location.
- Carefully prepare the area by removing debris, old adhesives, etc.
- Plan your layout and make all necessary plumbing, electrical cutouts prior to installing the backer board.
- Make sure the framing or substrate is securely fastened.
- Use backer board specific fasteners like backer board screws.
- Tape and fill all seams and gaps thoroughly.
- Allow proper drying and curing time before applying mortar.
- Always follow manufacturer’s recommendations.
Proper planning, using the right materials, and careful preparation at each stage will result in a backer board underlayment ready for quality tile installation.
Conclusion
Choosing and installing the proper backer board is one of the most important steps in a successful tile installation project. Cement backer board, fiber cement board, foam backer board, and fiberglass backer board each have ideal applications depending on the location and your specific needs. For most tile jobs, a traditional cement backer board with fiberglass mesh reinforcement provides the right combination of water resistance, strength, and workability. Carefully follow manufacturer instructions for fastening, seam treatment, curing times, and surface preparation for quality results. With the right backer board properly installed, you can look forward to years of durable, beautiful tiled surfaces.