To waterproof shower walls, you must first turn off the main water to your home and remove any faucets and showerheads in your shower. Next, remove existing tile and old wall material. Once you’ve stripped the wall to the studs, choose a backing board for your shower walls. Drywall is not waterproof, so you must use polystyrene foam, cement board, or cover water-resistant drywall with a waterproof membrane. Once you’ve selected your wall material, cut it to size and install it in the same manner you would install drywall. Then, seal the gaps between the boards with thinset tile mortar or another waterproof adhesive. Once you’ve completed these steps, your shower walls are waterproof and ready for tile installation.
Do You Need to Waterproof Shower Walls Before Tiling?
It’s essential to waterproof your shower walls before you install tile. If tile is installed on top of non-waterproof walls, the wall and tile installation will be destroyed. For instance, if you install tile on top of drywall, the wall will become infested with mold. It will begin to warp and decay. This will cause your tiles to fall off the wall.
- Shower walls must be waterproofed prior to tile installation.
- Non-waterproof shower walls will cause mold and decay in your walls.
- If your walls are not waterproofed, they will warp, bubble, and crumble, which will cause tiles to fall off.
- Learn why you cannot use regular drywall in a shower.
By waterproofing your shower walls prior to tiling, you prevent mold and mildew from infesting your home. A serious mold infestation caused by using the wrong wall materials can be expensive to fix. The moisture trapped in your walls if they are not waterproofed can even cause the wood studs in your walls to rot.
7 Steps to Waterproof Your Shower Walls Before Tiling
Before you install tile over your backer boards, it’s essential to complete the installation and waterproofing process. Below is the fastest and longest-lasting method for waterproofing your shower for tile.
Turn Off the Water Main
Before you can begin working on your shower, the main water supply to your home must be turned off. When installing new shower wall material and/or waterproofing membrane, all faucets and spouts in your shower must be removed. If the main water in your home is not turned off, water will gush from your pipes when you remove the faucets during shower remodeling.
- If your water is not turned off, water will run nonstop when you remove existing shower faucets and spouts.
- Your main water controls may be located at your water meter, near your hot water heater, in your basement, or under a metal cover at the sidewalk near your home.
- After turning the water off, open the hot and cold faucets to ensure there is no water running to them.
- If you cannot turn off your main water, contact a plumber.
To find your main water control, check your basement, near your water heater, your home’s exterior (near the water meter), and at the street for water main controls. If you cannot identify the water main or cannot turn it off, contact a plumber. If you believe you have turned off the main water, test this by turning on the faucets in the bathroom. If the water stops completely once both the hot and cold taps are open, your water is off and it’s safe to proceed.
Remove showerheads, tub spouts, and shower control handles before proceeding. Most showerheads and tub spouts can be removed by twisting them counterclockwise. A plumbing wrench can help if you have a stubborn spout. Faucet handles can be more difficult to remove. Depending on your faucet handle, it may be held in place by set screws or screws hidden behind a faceplate.
- Unscrew showerheads and tub spouts by turning them counterclockwise.
- Use this pipe wrench to unscrew stubborn tub spouts.
- Look for the set screws that hold faucet handles in place.
- Remove all fixtures until only bare pipes are sticking out from your wall.
Removing these plumbing fixtures allows you to properly waterproof your shower walls. It also makes removing or installing backer board much easier in future steps. You cannot leave these fixtures in place during the waterproofing process.
Tear Out Existing Tile and Wall Material
If you are installing new waterproof board in your shower, you must first remove the existing tile installation and backer boards. Use a hammer and pry bar to pop off the old tiles and discard them. Then, remove the backer boards so that the wall studs in the shower are fully exposed. You cannot install new backer boards on top of your existing wall material.
- Remove an existing tile installation by using a hammer and crowbar.
- Tear out the old wall material until the wall studs are bare.
- Never install waterproof board over your existing wall material—this can trap moisture and cause mold.
- If you are waterproofing existing shower walls, make sure they are made of safe material. Then, install a waterproof membrane.
If you are waterproofing existing shower walls, make sure they meet building codes. The shower walls must be either made of waterproof board or at the very least, must be water-resistant drywall. If the existing walls are regular drywall, they must be removed and replaced. If your current shower walls are water-resistant drywall, follow our guide to waterproof drywall for your shower.
Choose a Backing Board
When installing shower walls, it’s best to use a waterproof backing board. Extruded polystyrene foam board is lightweight, high quality, and easy to install. cement board is a classic option, but it is heavier and a bit harder to work with. However, both are good choices for shower surroundings.
- This polystyrene foam board shower kit is a great choice for a waterproof shower.
- Instead of foam board, you can use sheets of cement board purchased from your local hardware store.
- If you are using drywall for your shower walls, it must be water-resistant (green) drywall.
- Water-resistant drywall must be further waterproofed by installing this glue-on membrane on top of the drywall—this adds an extra installation step.
You can use water-resistant drywall (commonly called greenboard) but it must be waterproofed by gluing a waterproof membrane on top of it. Liquid membrane that you paint on is not sufficient for waterproofing drywall. You should never install shower tile or waterproof membrane over standard drywall. Since using drywall requires specialized drywall followed by waterproof membrane, it’s faster and easier to install waterproof backing board instead.
Cut Your Backing Board to Size
Once you have chosen your wall material, it must be cut to size to fit your shower. Measure the wall and mark your wall board with straight lines to fit these dimensions. Make sure to mark and cut holes for plumbing to pass through. Any holes should be as small as possible, so take your time measuring and cutting your board. It’s best to measure and cut one board, screw it in place, then measure and cut the next board.
- Measure your wall to find the dimensions the backing board must fit.
- Mark your backing board with straight lines where it needs to be cut.
- Cut backing boards in straight lines by scoring them with this utility knife, then snapping the board along that line.
- Cut circular holes for plumbing pipes using this drywall saw.
Shower backboard can be cut in straight lines by using a utility knife to make a cut. Then, snap the board along these lines. Use a sharp drywall saw to make circular cuts for plumbing. If you want to avoid some of this work, use Schluter Systems shower kits that feature holes or slits for plumbing to pass through.
Hang Your Backing Board
Install your properly-sized backing board by screwing it to the wall studs. Screws should be driven through the board and into the studs every 16 inches (40 cm). It’s best to use drywall screws 1 ¾” in length.
- Secure your measured and cut backing boards directly to the wall studs.
- If you are not using a shower kit with screws included, these drywall screws will work perfectly.
- Drive in 1 screw every 16 inches (40 cm) along each wall stud to properly secure your wall board.
- Gaps between boards should be no larger than ¼-inch (6 mm) to allow them to be properly sealed in the following step.
Although a snug fit between neighboring boards is desirable, it’s okay if there is as much as ¼-inch (6 mm) of space between boards. These gaps will be sealed and waterproofed in the next step.
Seal Seams in Your Backing Board
To seal seams between Schluter system boards, use the pipe gaskets and waterproof membrane tape included in your kit, along with the included adhesive. If your shower walls are made of cement board, use mesh drywall tape held in place with thinset adhesive. Paper tape and standard joint compound will not hold up to water exposure, so you cannot use these materials.
- Seals seams where polystyrene foam boards meet using this membrane and this waterproof adhesive.
- Use these pipe seal gaskets to waterproof wherever pipes pass through holes in your backer board.
- Seal seams between cement boards with plastic mesh drywall tape and thinset mortar.
- Never use paper tape and/or joint compound to seal seams in a shower—they will be destroyed by water.
It’s much easier to seal gaps between pipes and the surrounding board if you use specialized gasket seals held in place with adhesive. By sealing gaps between boards, as well as where pipes pass through your wall board, you prevent water from infiltrating your wall. This creates a waterproof wall that is ready for tile as soon as the adhesive dries.
How Do You Waterproof Your Shower Walls for Tile?
To properly waterproof your shower before you install tile, you must:
- Turn off the main water to your home.
- Remove all shower heads, faucets, and spouts in the shower.
- Tear out existing tile and backer board.
- Choose a waterproof backer board made of polystyrene foam or cement.
- Cut your backer board to size.
- Screw your backer board directly to the wall studs.
- Seal the gaps between boards with waterproof tape and adhesive.
This system is far more durable than liquid waterproofing membranes painted over drywall. You’ll have a shower that will hold up for generations. Plus, waterproof backer board is much easier to install than a glue-on membrane. Once you’ve completed these steps, you can simply spread thinset mortar on your backer board and start tiling.