Over the years, many contractors and homeowners have gone to remodel a bathroom to find the drywall behind their tile has developed mold.
This can be a serious health concern, and it is why tiling over drywall in a shower is considered a bad practice.
The better, safer option, in this case, would be to use a shower wall panel. But since many people will commonly tile over their drywall, we should elaborate on this topic.
Should You Put Tile on Drywall in a Shower?
Tiling over drywall is perfectly fine and safe on a fireplace or even a kitchen backsplash as they do not constantly get hit by moisture.
But it is not something that I would recommend when it comes to wet areas.
Your shower is probably the wettest and most moisture-prone area of your home.
And it is the one area in your home where I would advise you not to tile directly over the drywall.
Many drywall manufacturers will claim their drywall is perfectly safe to use in a shower.
Regardless of the drywall you purchase or already have, it is made of gypsum and paper and does not do well with moisture at the end of the day.
There are certain moisture-resistant drywall products out there, but none are waterproof.
Even the most moisture-resistant drywall over time will take in water through the tile and create mold.
Drywall can be used as an interior insulator, but you should use a waterproof material over the drywall as your actual backing for the tile.
Things to Consider When Installing Tile Over Drywall in a Shower
Where the drywall is placed in your bathroom can make a world of difference.
Having drywall only on the upper half of your shower wall will allow you to tile directly onto the drywall.
This is because the water in your shower only rarely hits the top half of your wall.
The minimal amount of splashed water that hits the top half of your wall can be blocked by your tile.
It is when the tile is constantly being hit by water pressure that the liquid will seep through.
Mold should be your primary concern and the main reason you should not tile over the drywall in your shower.
Depending on how often your shower is used, it can take many years for mold to develop, but it is inevitable.
The longer the mold grows, the more of a threat to your health it can become.
Once the grout on your tile starts giving out or the tile itself is damaged, the mold spores will be able to slip out.
Or worse, get into your HVAC system and spread through your home, causing health issues.
Besides the health concerns of mold, it can also cause irreparable damage to your wall.
Water can also cause the drywall to warp or rot. This will, of course, cost you time and money.
Minor water damage could be considered a viable DIY project. But with significant water damage, you are best off replacing all of the damaged walls or calling professional help.
In addition, damaged walls can let outside creatures, such as insects and rodents, into your house.
How to Prepare Shower Drywall for Tile Installation
Though I advise against it, you should make certain preparations if you absolutely must tile over drywall in your shower.
Begin by purchasing the best moisture-resistant drywall you can afford. This in no way will guarantee you moisture resistance, but it is somewhat better than using regular drywall.
The next step would be to waterproof your drywall. There are a few methods to achieve this.
One would be to use a waterproofing primer paint made specifically for drywall. To ensure moisture-free drywall, you can follow up your waterproof primer with waterproof paint.
Another option is to use one of the many waterproof membrane or sealant products that exist on the market.
But even after all these drastic measures are taken, they cannot guarantee you waterproof drywall.
Make sure your drywall is as smooth and straight as possible, making applying your tile much more effortless.
After your tile and drywall have been installed, you can take certain measures to help keep your drywall dry.
You must get all the moisture off your tile within 48 hours of running the shower.
This can be done with a fan or by hand with a towel. You can also buy a dehumidifier for your bathroom.
Over time you can depend on your nose. If you smell a musty or sour smell in your bathroom, there is a chance that mold has taken hold of your drywall.
Cement board is an excellent alternative to using drywall. It will not warp or mold when exposed to water, giving it a significant advantage over drywall.
The downsides of cement board are that it is more expensive.
Cement board can also be harder to install because drywall comes in 4-by-8 sheets while cement board comes in 3-by-5 sheets making installation on large walls more labor-intensive.
Shower Wall Panels
Shower wall panels are another good alternative to drywall, though generally, you will not be able to tile over them.
The trade-off of not being able to tile over them is that there are many styles and finishes, some that even imitate tile.
Shower wall panels are waterproof, so mold will not be a worry. But you will need to pay more for these panels than you would for drywall, and installing them will require more time and effort.
Lath and Plaster
Lath and plaster will give you a great surface to place tile over. Plaster is relatively cheap, so the price is equal to or less than drywall.
But there are two issues that come with using lath and plaster.
First off, the installation process can be more challenging than drywall or any of its alternatives because you will have to trowel the plaster on your wall by hand.
Secondly, plaster is not waterproof.
Plaster will not develop mold, so there are no health concerns. Instead, water can cause plaster to warp and expand, which can cause damage to your walls.
The bottom line, you can tile over the drywall in your shower, but it is not considered a good practice as this potentially can cause health problems for you and your family.
Making drywall waterproof takes a lot of work both before and after installation, and it cannot be guaranteed, so you are better off using one of the drywall alternatives listed above.
For many years people built homes with drywall in the shower, and for a time, we didn’t see a problem with it.
Over the last 15 or 20 years, many of us have realized that drywall is a terrible material to use in the shower.
Drywall manufacturers have tried to combat this by developing new moisture-resistant drywall products.
But ultimately, you are better off choosing a different material, and you have plenty of options.