Installing a beautiful new backsplash can transform the look of your kitchen or bathroom. But before tiling, an important question arises – do I need cement board for the backsplash? Understanding cement board, also called drywall, and its role in backsplash installation is key. This extensive guide covers everything you need to know about cement board for backsplashes to make your project a success.
What is Cement Board?
Cement board, also known by the brand name HardieBacker, is a construction material used as an underlayment for tiling projects. It consists of an engineered cement formulation reinforced with fiberglass mesh on both sides.
Compared to regular drywall, cement board is highly water-resistant and designed for high-moisture areas. It provides an ideal surface for installing ceramic, porcelain or natural stone tile. Cement board will not degrade or decompose over time when exposed to water.
Key Properties of Cement Board:
- Waterproof surface for wet areas
- Durable and crack resistant
- Materials won’t deteriorate or rot
- Creates a strong tile backing
- Allows for a thinner installation compared to a mud bed
- Works for both walls and floors
Cement board comes in a variety of sizes, like 1/4 inch, 1/2 inch and 5/8 inch thicknesses. Thicker boards provide more sturdiness for floor installations. Cement board weighs approximately 2 lbs per square foot.
Why Use Cement Board for Backsplashes?
Cement board offers a number of benefits that make it the top choice as a backsplash substrate:
Prevents Moisture Damage: Backsplashes get splashed with water constantly above countertops and sinks. Cement board’s waterproof nature prevents water damage, deterioration and mold growth.
Impact Resistance: Cement board is durable and resists cracks much better than drywall alone. This is useful in high traffic areas like kitchens.
Thin Installation: At just 1/4 – 1/2 inch thickness, only a thin layer is needed behind tiles for a level surface.
Consistent Surface: The reinforced fiberglass mesh provides a consistent and reliable backing surface to adhere tiles to.
Fire Resistance: Cement board is non-combustible and fire resistant. It adds an extra layer of protection behind stoves.
Mold Resistance: With water resistance comes mold and mildew resistance, which is very useful in humid areas like bathrooms.
For these reasons, cement board is considered a best practice for most backsplash installations. The waterproofing and durability provide long-lasting performance.
Do You Have to Use Cement Board for a Backsplash?
While cement board is highly recommended, it is not an absolute requirement for backsplash installation in all cases. Here are some instances where you may be able to use alternatives:
- Low-moisture environments – Cement board provides waterproofing that may not be necessary for backsplashes far from water sources. Areas not prone to splashing or condensation may allow drywall alone.
- Tile with a resin coating – Impervious porcelain or ceramic tiles with a baked-on resin face don’t require the waterproofing capacity of cement board. The tiles themselves seal out moisture.
- Backsplashes on exterior walls – Concrete block or brick exterior walls are inherently water-resistant surfaces suitable for tiling onto.
- Temporary backsplashes – For a rental home or interim backsplash, drywall could work since it doesn’t need long-term durability.
However, even in those situations cement board is still a smart idea for impact resistance and mold prevention. For most backsplash projects, cement board is strongly advised. It provides that extra level of reliability and performance.
Cement Board vs. Drywall for Backsplashes
How does cement board compared to drywall for backsplash installation? Here’s a look at the pros and cons:
Cement Board Benefits:
- Waterproof surface
- Crack and impact resistant
- Provides consistent backing for tiles
- Won’t deteriorate or rot from moisture
- Fire and mold resistant
- Less expensive
- Easier to cut and install
- Familiar material for DIYers
Drywall is certainly cheaper and more DIY-friendly. But it lacks durability and moisture resistance. The fibroglass mesh in cement board gives a much more reliable bonding surface for tiles. For long-lasting backsplash performance, cement board is worth the extra effort and cost.
Can You Tile Directly to Drywall?
Technically, yes – tiles can be installed directly onto drywall. The key question is whether that installation will hold up over time.
Drywall is prone to crumbling and water damage when tiled over. Joint tape and compound can deteriorate with moisture exposure. This leads to cracks as the drywall loses integrity.
Without cement board, drywall typically requires additional preparation:
- Sealant coats like RedGard or Kerdi to waterproof
- Anti-fracture membrane for crack prevention
- Skim coating with mortar for a bonding surface
These steps help compensate for drywall’s lack of natural waterproofing. But they add complexity, while cement board is designed as an ideal tiling substrate right off the bat.
Many pros still recommend cement board despite added drywall prep. Long term, it provides the most worry-free installation and best prevention of tile cracking and loosening.
Can You Put Cement Board Over Drywall?
Fortunately, it’s easy to enjoy the benefits of cement board even on top of existing drywall:
New Installation – For new backsplashes, install 1/4″ or 1/2″ cement board over the drywall with thinset mortar. This allows you to take advantage of the drywall’s fire rating and acoustic insulation while still gaining a waterproof cement board layer for tiling.
Existing Drywall – Use screws and thinset to fasten cement board over drywall. Skim coat if needed to flatten the area first. This upgrades an existing backsplash by replacing the drywall while keeping the same footprint.
So cement board can be integrated into backsplashes with drywall in the wall assembly. The key is getting that durable cement surface as the final backing before laying tile.
How Thick Should Cement Board Be for Backsplash?
For walls and backsplashes, 1/4 inch and 1/2 inch are the recommended cement board sizes:
- 1/4 inch – Best for backsplashes and vertical installations. Provides adequate strength while keeping boards lightweight and thin.
- 1/2 inch – Offers extra impact protection for potentially damaged areas. Good for accent walls or behind cooktops.
- 5/8 inch – Overkill for backsplashes and harder to cut. Best reserved for floor installations.
1/4 inch boards are fine for most backsplash areas. 1/2 inch can work for heavy duty zones or large format tiles. Avoid 3/4 inch or greater thicknesses – excess weight makes installation trickier on walls.
How to Cut Cement Board
Cement board requires special techniques for cutting:
- Use carbide tipped scoring knives or cement board shears. Carbide blades last longer than standard metal when cutting through the fiberglass mesh.
- Avoid high-speed blades – cement board dulls normal circular saw teeth quickly.
- Score deeply then snap the panel for clean breaks. Make multiple passes with the knife.
- For circular holes, use carbide drill bits and drill from both sides to prevent fraying.
- Minimize dust by cutting outdoors or using wet methods. Use an N95 mask.
Practice first on scrap pieces to get used to cement board’s hardness before moving onto finished cuts. Allow extra time for accurate cuts.
How to Install Cement Board on Walls
Follow these best practices when installing cement board:
- Start with bare wall studs exposed. Remove any drywall or old materials.
- For moisture-prone areas, apply waterproofing like RedGard to studs first.
- Cut boards to size and test fit before final fixing. Measure twice and cut once.
- Fasten boards with specialized cement board screws, not nails or drywall screws. Use 1-1/4″ screws spaced 8″ apart across fields and edges.
- Position boards vertically for strength. Offset seams from underlying studs.
- Leave 1/8″ gaps between boards. These allow for expansion and prevent buckling.
- Fill seams and gaps with acrylic sealant or thinset mortar for waterproofing.
- Avoid placing seams near sinks, faucets or behind stove tops where leaks are most likely.
- Arrange boards so edges meet at stud centers for best support.
With planning and careful installation, cement board creates a robust tiling substrate. Check manufacturer instructions for additional tips.
Applying Thinset to Cement Board
Thinset mortar is used to stick tiles to cement board. Follow thinset directions for proper mix consistency. Key tips:
- Only apply enough thinset that can be tiled over before drying. Work in smaller sections.
- Use the flat side of the trowel first to key thinset into the board. Then use a notched trowel to even ridges.
- Spread thinset evenly to fully support tiles. Avoid bare or thin spots.
- Push tiles firmly into place while thinset is still wet and tacky.
- Check thinset coverage by lifting a tile – there should be at least 80% adhesive transfer showing.
- Allow thinset to fully cure for 24-48 hours before grouting.
With the right thinset application, tiles will bond securely to the cement board substrate.
Can You Apply Tile Directly to Cement Board?
The combined thickness of cement board and tile can tilt tiles outward if applied directly. To avoid this shelf effect:
- Use a leveling system like tile spacers or clips when installing tiles to keep surfaces flat and smooth.
- For thicker natural stone tiles, apply a mortar bed on the cement board first. This raises the tile surface level before adding thinset and tiles.
- If dealing with an uneven wall surface, use self-leveling underlayment over the cement board to create a flat base.
With extra planning, tiles can be mounted directly onto cement board successfully. The flatter the surface, the better.
Do You Have to Seal Cement Board Before Tiling?
Sealing cement board provides extra moisture protection at vulnerable seams and corners. The main options include:
Mesh Tape and Thinset – Embed fiberglass mesh tape into thinset mortar at all cement board joints. Feather thinset 2″ beyond tape edges.
Acrylic Sealant – Apply waterproof acrylic caulk along seams and corners. Smooth with a finger or caulk tool.
Waterproof Membrane – Roll on a full water barrier like RedGard over the entire surface before tiling.
Sealing is not mandatory, but it does add cheap insurance against leaks. Mesh tape with thinset is commonly recommended as the minimum.
Do I Need to Prime Cement Board Before Tiling?
Priming refers to coating the cement board with a bonding agent so the thinset adheres better. Often this is unnecessary:
- Modern thinset mortars already contain polymers and bonding additives.
- Cement board’s natural concrete surface doesn’t require special treatment.
- Portland cement-based thinsets bond well directly to cured concrete board.
Primers like Mapei’s Eco Prim Grip are mainly beneficial:
- When using specialty non-cement thinsets like epoxy or urethane. These benefit more from grip coatings.
- In hot and humid climates where cement board is more porous.
- For increased water protection with an acrylic primer.
For most tile jobs and regular thinset, priming cement board is not required. Check your thinset manufacturer’s recommendations.
Grout Options for Cement Board
Any standard sanded grout for floor tile works fine for cement board walls. Unsanded grout is also popular for backsplashes:
- Sanded grout – Best for joints 1/8″ and wider like floors. More durable and shrinks less. Scrub excess off the surface.
- Unsanded grout – For narrow wall joints under 1/8”. Smoother finish and less dusty. Easier for DIY but more prone to cracks.
- Epoxy grout – Extremely durable and waterproof but requires extra skill. Ideal for wet areas.
Match the grout texture and performance to the types of tile and joints. Any grout suitable for floor tile also works with cement board backsplashes.
Tips for Tiling on Cement Board
Follow these tips when tiling onto cement board:
- Use high quality thinset mortar designed for cement board. Follow mixing and application instructions.
- Check thinset consistency – should be toothpaste-like. Adjust water amounts as needed.
- Let thinset slake or sit 5-10 minutes after mixing. This allows it to fully hydrate before use.
- Use the flat trowel side first to work thinset into the board texture before combing ridges.
- Make sure tiles are completely set before grouting. Don’t walk on floor tiles prematurely.
- Clean excess grout within 25 minutes of application using a grout sponge.
- Apply grout sealer once fully cured to maximize stain resistance.
Proper materials and application techniques will ensure tiles adhere tightly.
Can You Install Cement Board Vertically?
Yes, cement board can be installed vertically for walls and backsplashes. The fiberglass mesh keeps it rigid enough to support itself upright.
Here are some tips:
- Use full 4×8 sheets and cut to maximize backing at seams.
- Attach boards every 6-8 inches along studs so weight is fully supported.
- Position boards so edges meet at stud centers rather than spanning between them.
- Keep fastener heads flush to prevent bumps behind the tile.
As long as enough screws anchor the cement board at studs, vertical installation is reliable. Small boards may need more frequent fastening.
Typical Backsplash Heights
Standard backsplash heights help guide cement board coverage areas:
- 4 inch – Protects directly behind cooktops or sinks. Provides minimal splashing protection.
- 6 inch – Most popular standard size. Offers decent water protection while allowing more wall visibility.
- 8-10 inch – Great foraccentuating kitchen designs while increasing the splash zone. Common with subway tiles.
- Full height – Makes the entire wall a focal point. Best for light use areas due to grout maintenance.
Of course, heights can be customized to your space. Just make sure cement board extends to adequately support the full backsplash.
Low Profile Backsplash Alternatives
For minimal-depth backsplashes, some thin alternatives to cement board include:
PVC Panels – Waterproof plastic sheets adhered with silicone. Easy install but less durable long term.
Stainless Steel – Hygienic metal option. Affordable sheets mount directly to walls.
Tile Stickers – Peel-and-stick backsplash tiles or decals. Temporary solution with simpler installation than real tile.
Painted Drywall – Low cost choice for buyers on a budget. Lacks dimension and vulnerable to damage.
While cement board is still best for directly tiling on, these create thinner backsplash options weighing under 1 lb per square foot.
Can You Install Cement Board on Metal Studs?
Metal framing in commercial buildings or high-rises often uses metal studs instead of wood. Cement board fastens fine to these:
- Use self-tapping drywall screws designed for metal framing. Avoid large lag bolts.
- Ring shank screws grip better on smooth metal compared to coarse threads.
- Drill pilot holes through cement board and studs to avoid screw deflection.
- Drive screws perpendicular to the stud face. Angle slightly towards vertical for walls.
- Follow normal spacing – 8″ on center staggered in the field and along edges.
With specialized screws, cement board installs securely on metal just like for wood stud walls. Ensure screws sink flush.
How to Join Multiple Cement Board Sheets
When needing to span larger areas, joining multiple cement board sheets is common. Here’s how to seam them together:
- Align edges neatly leaving a 1/8” gap between sheets to allow for expansion.
- Attach 2×4 lumber strips along the seam as backing for adhesion. Screw into studs.
- Embed alkali-resistant mesh tape into thinset mortar over the gap and screws.
- Feather thinset 2” beyond the tape perimeter. Let fully cure before tiling.
Joined correctly, the seam becomes as durable as a single panel. Screw backing provides stiffness across the joint.
Typical Sheet Layouts
Here are some common cement board sheet layouts for efficient cuts:
Half Sheets – Rip 4×8’ sheets in half lengthwise for 4×4’ pieces. This creates less waste for tall narrow spaces.
Third Sheets – Rip into 16” vertical strips to offset seams when covering full 8’ height.
Cut Around Openings – Measure and cut holes for outlets and windows. Align edges with studs.
Irregular Accents – Make L-shaped pieces to border countertops or range hoods.
Cut sheets into sizes that maximize coverage while keeping seams on secure stud anchors.
Can Cement Board Get Wet During Installation?
It’s best to keep cement board dry during storage and installation. However, getting cement board a little wet is not detrimental:
- Cement board can withstand incidental exposure to moisture as it’s waterproof. A bit of rain won’t hurt it.
- Brief contact with water won’t weaken cement board or affect its performance.
- Laying boards flat helps water drain off and speeds drying. Keep it covered when not actively installing.
Prolonged soaking or immersion should still be avoided