Drywall is not an adequate backing material for a tile shower. Even moisture-resistant drywall (often green or blue in color) is not durable enough to withstand water exposure. Over time, the drywall will deteriorate from moisture, causing your tile to sag, crack, or fall out. It’s essential to use an appropriate backing material, such as cement board or Kerdi-Board, for your shower walls before tiling. This will result in a durable tile surface.
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Why Is it Bad to Tile Over Drywall in a Shower?
There’s no such thing as waterproof drywall. Drywall simply can’t hold up to the water exposure it undergoes in a shower environment. Even the best tile job won’t be able to prevent drywall from becoming soggy from water exposure or condensation. Tiling over drywall leads to mold, deteriorating drywall, and moisture in your walls that causes wood studs to rot.
- Mold will form on drywall where it is used in showers.
- Drywall will crumble or sag, causing your shower tiles to crack or come loose.
- Wooden wall supports will be in constant contact with wet drywall, which causes rot.
- Tile can be applied over drywall in kitchens and other areas—just not in showers.
You can tile over drywall in kitchens, around fireplaces, or in other areas where the wall does not come into direct contact with moisture. For showers, special steps must be taken to make sure your tilework stands the test of time.
What Backing Material Do You Need When Tiling a Shower?
It’s essential to moisture-proof your shower before tiling. This means you need to use an appropriate backer board to replace any existing drywall, as well as seal and protect that backing material with waterproof joint sealing products. Standard drywall, tape, and joint compound, and other materials have no place in a shower because they will break down. Below is everything you need to truly prepare your shower for tiling.
When you are preparing your shower for tile installation, first remove any existing drywall. Once you have stripped your wall to the studs, you can prepare for tiling. If you are using a traditional cement board as your backing board, you will need to install a plastic vapor barrier directly on top of the wooden studs in your wall.
- Install this plastic sheeting over studs before installing a cement board.
- A vapor barrier acts as a waterproof membrane that prevents wood behind your backer board from rotting.
- If you are using a new style of backing board, such as HardieBacker or Kerdi-Board, no vapor barrier is necessary.
It’s important to note that many new backing board systems do not require a moisture barrier to be installed. You can skip this step and save yourself some work by going with one of our personal favorite shower backing systems—Kerdi-Board or HardieBacker.
There are several backing boards available on the market that can be used for your shower. All of them are better than both regular drywall and any water-resistant drywall on the market. You can use cement board, or a specialized backing board, such as Kerdi-Board, Wedi-Board, or HardieBacker.
- A cement board is a classic shower-ready backing board.
- There are several backing boards available on the market. This shower install kit from Kerdi-Board has everything you need to prepare your shower for tiling.
- Never use drywall as a shower backing. Even water-resistant drywall isn’t suitable for showers.
Do not cut corners and use water-resistant (green or blue) drywall in showers. While these drywall varieties can hold up as walls in other parts of your bathroom, they aren’t durable enough for a shower. They will deteriorate after the ceramic tile has been installed on top of them.
The joints between your backing board will need to be taped and floated to truly make them waterproof. However, traditional paper tape and mud aren’t waterproof. You’ll need to use waterproof tape or fiber tape to create a backing surface for your tile that won’t break down.
- This waterproof backing tape is good for showers where a specialized backing board has been used.
- Use this fiber tape to seal joints between cement boards.
- Never use traditional drywall tape to seal joints in your shower backing board.
Specialized shower install kits will include waterproof tape, as well as tape seals to waterproof around pipes and faucets. Using a complete shower kit can make taping joints in your shower much easier.
Specialized Joint Sealant and Caulk
In the same way you need specialized tape for the joints between your shower backing board, you also need a joint compound that won’t break down when exposed to water. Standard drywall mud will deteriorate quickly when used as a tile substrate. The following products can be used to hold your waterproof tape in place and tile-prep your shower.
- Use this joint sealant in corners, seams, and where your backing board meets your tub or shower pan.
- Apply this sealant-like joint compound to keep your waterproof tape in place over joints in backing board.
By using the correct backing board, tape, and sealant, you set yourself up for success. Your shower walls will be prepared for tiling and you won’t have to deal with moldy, soggy drywall ruining your work.
Can You Tile Over Greenboard in a Shower?
Greenboard is not rated for showers and will not hold up for this application. Greenboard is water-resistant drywall, which means it is suitable for the walls of a bathroom, but not the shower itself. If it is installed in a shower and tiled, Greenboard will begin to mold and break down. You will be left with a mold-infested mess if you tile over Greenboard. Use a specialized backing board, such as Kerdi-Board instead.
Can You Tile Over Normal Drywall in a Shower?
Never use standard drywall in a shower. It will deteriorate even faster than Greenboard. Often, the entire wall will become so soft that it will flex inward when you press it. This is because drywall is not meant to be exposed to moisture. Avoid all types of drywall when creating a backing for tile in your shower. Only use approved waterproof backing board.
How Do You Waterproof a Shower Wall Before Tiling?
Before tiling your shower, remove any drywall that is present. If your shower was previously built with drywall walls, you will need to strip it down to the studs. Then, install a waterproof backer board, such as Hardi-Backer or Kerdi-Board. Seal the joints in the backer board with waterproof tape and joint sealant. Then, your shower is ready for tiling.