Can You Tile Over Drywall in a Shower?
You shouldn’t put tile on top of drywall in the shower. As you know, the shower is exposed to water on a daily basis.
While shower tiles should be water-resistant, moisture will get through them at some point. It’s especially likely to seep through gaps in the grout or cracks in the tiles.
When that happens, the drywall won’t be able to stand up to the moisture. Wet drywall becomes soggy and crumbles. It becomes an ideal home for mold to grow, and it invites pests to invade.
Not only that, but wet drywall can channel moisture toward the wooden wall studs. Waterlogged studs will eventually need to be replaced.
Signs of Drywall in the Shower
How can you tell if there is drywall behind your shower tiles? While there’s no sure-fire test without removing the tiles to look, there are some signs that indicate that you may have this issue.
Wet drywall loses its strength. As a result, when you push gently on the tiles, it may feel like the wall behind them gives way. Also, the drywall might not be able to hold onto the tiles. Some of them might be falling off the wall.
Mold and mildew provide other clues to a drywall issue within your walls. Black stains may appear in the tile grout or along the caulk at the edges of your shower. Even if you are able to remove the stains with bleach or other cleaners, they may return after just a few weeks or months.
If you notice any of these problems, take them as a sign that it’s time for a renovation project. Even if you weren’t planning to remodel your bathroom right now, you’ll want to rethink that. The sooner that you remove the old tiles and rip out the drywall, the sooner you can replace them with a longer-lasting arrangement.
Drywall Alternatives for Showers
Now that you understand what a problem regular drywall in the shower is, you might wonder if water-resistant drywall is an acceptable alternative. It isn’t. While it might hold up a tiny bit longer than standard drywall, it won’t last any better in the long run.
Plain plywood isn’t a good alternative either. It will soak up moisture just like drywall or wall studs.
Instead, you need a product that’s meant for jobs like this. The most common choice is a cementitious backer unit, also known as cement backer board. This material is constructed of inorganic materials that, unlike those used for drywall, won’t soak up water or be ruined by moisture exposure. Be sure to use drywall tape and mortar between each sheet of backer board.
In addition to cement backer board, you’ll also need to install a moisture barrier. There are a few different options. Plastic sheeting can be placed between the wall studs and the cement board. The other option is to put a membrane product on top of the backer board. Membranes come in both liquid and sheet forms. Alternatively, there are also cement boards that come with built-in moisture barriers.
There’s one exception to the no-drywall rule. Some sheet membranes are acceptable for use over drywall. Liquid products, on the other hand, should never be applied on top of drywall.
Where to Restart the Drywall
The cement backer board should extend to the height of the showerhead, but you don’t need to use this water-safe material above that level. Drywall can also be placed in the non-shower areas of the bathroom.
If you take care to use only waterproof materials for walls exposed to the shower’s spray, you’ll be on your way to designing a strong, beautiful tile shower.