Hey there! If you‘re installing or upgrading the shower in your bathroom, properly sealing the drywall around the enclosure is crucial to prevent leaks, moisture damage, and mold growth. As a home improvement expert who has remodeled dozens of bathrooms, I‘m going to walk you through the entire process step-by-step so you can get professional, watertight results.
Why Sealing the Drywall is So Important
Let‘s start by going over exactly why it‘s so important to properly seal the drywall in your bathroom around the shower.
Prevent Water Damage
Water leakage into drywall can cause major damage over time. According to the EPA, household leaks account for nearly 1 trillion gallons of water wasted each year in US homes. The average family of four can waste as much as 10,000 gallons per year from leaks that go unfixed!
Preventing water from seeping into your bathroom walls is the only way to stop this damage and waste. Even moisture in the air can soak into drywall and cause issues. Properly sealing the enclosure will act as a waterproof barrier.
Stop Mold Growth
Mold thrives in damp environments with excess moisture. If water seeps through the tile grout or leaks through gaps in the enclosure, it will lead to mold taking root inside your walls.
According to the CDC, exposure to mold can cause a variety of health issues like coughing, wheezing, and irritation. Mold remediation is also extremely expensive. Sealing the drywall ensures no moisture can get in and prevents hazardous mold growth.
Avoid Expensive Repairs
If you don‘t take steps to seal the drywall and problems arise, repairs can be very costly. The average price to replace a section of damaged drywall is $400 to $900. Extensive mold remediation can cost thousands.
Properly sealing around your shower enclosure is a small investment that saves huge expenses down the road. An ounce of prevention is absolutely worth a pound of cure when it comes to showers and tubs!
Choose the Right Materials
To do this project right, you need the proper materials. Here‘s exactly what I recommend using:
- Greenboard – Greenboard drywall has a moisture-resistant facing that will hold up much better than regular drywall. It has glass fibers embedded into the paper to reduce wicking.
- Cement backerboard – Cement board provides a super rugged and waterproof layer behind the tile and where the enclosure meets the walls.
- Acrylic caulk – For most gaps I recommend using a flexible, acrylic-based caulk that contains silicone. Look for one labeled "mold resistant."
- 100% silicone – For gaps directly adjacent to the shower floor and walls, use a 100% silicone caulk without acrylic.
- Thinset mortar – Needed to adhere the cement backerboard and tile edging strips.
- Waterproofing membrane – Roll or paint on 2-3 layers of a membrane like RedGard or Hydro Ban.
- Tile edging & trim – Cover raw tile edges and make a decorative transition from the surround to walls.
Now let‘s go step-by-step through this process together!
Step 1: Install the Shower Surround
The first step is installing your tub surround or shower enclosure according to the manufacturer‘s instructions. Most surrounds need to be adhered directly to cement backerboard rather than drywall.
If your surround will get attached right to drywall, be sure to use greenboard and apply a waterproofing membrane over it prior to attaching the surround.
Ensure the walls are plumb and square before permanently affixing the panels. Taking your time here will prevent issues down the road.
Step 2: Cut and Install the Greenboard
Once your surround is securely in place, take measurements and cut greenboard panels to fit snugly around it. Make sure any seams between panels fall directly over wood studs so they are properly supported.
Use drywall screws driven just below the surface to affix the greenboard to the studs. Try to keep screw heads flush with the surface to make finishing easier.
Greenboard cut and installed securely to wood studs
Step 3: Tape and Mud the Seams
Just like regular drywall, you‘ll need to properly tape and mud the seams between panels. Use fiberglass mesh tape and drywall joint compound for this process.
Apply a thin layer of compound over each seam and use a paint roller to flatten and adhere the tape. Allow to fully dry overnight before adding a second coat to feather out the edges.
Lightly sand and finish with a third coat if needed to get a nice smooth finish. Take your time with the mudding to prevent cracks.
Step 4: Roll On Waterproofing Membrane
Once the greenboard is up and seams taped, the entire surface needs to be coated with a waterproofing membrane. RedGard, Hydro Ban and Laticrete Hydro Barrier are all excellent options.
Use a paint roller to apply 2 coats, allowing the first to dry completely before adding the second. This seals the greenboard and acts as your water barrier between the tile and drywall.
Rolling on two coats of RedGard to waterproof the greenboard
Step 5: Install Cement Board Around the Surround
Now it‘s time to cut and install cement backerboard around the bottom and sides of the surround. This adds reinforcement at the transition between the surround and walls.
Use thinset mortar to adhere the backerboard pieces. Make sure they are nice and flush with the front surface of the surround.
Fill any gaps between the cement board and surround with thinset for a seamless transition. Let the mortar fully cure overnight before moving on.
Step 6: Waterproof the Cement Board
Just like you did with the greenboard, it‘s important to apply 2-3 coats of waterproofing membrane over the cement backerboard. This seals it and provides one continuous waterproof barrier.
RedGard or Hydro Ban are excellent choices here as well. Let each coat fully dry before adding the next. Your cement board is now primed for tiling!
Step 7: Install Transition Strips
Next, spread a layer of thinset mortar along the cement board where it meets the bottom edge of the surround. Press transition strips of backerboard or plastic into the mortar to cover the raw cement board edge.
Also adhere tile edging along the seams between the surround and cement board with thinset. This provides a decorative finished edge. Let the thinset fully cure before moving to the next steps.
Attaching a plastic transition strip along the bottom with thinset mortar
Step 8: Caulk All Seams and Gaps
Now it‘s time to caulk. Go around the entire surround and seal any gaps or seams with a quality tub and tile caulk. Focus on these key areas:
- Where the surround meets the tile edging strips
- Where the tile edging meets the greenboard or cement backerboard
- Where plastic/backerboard transition strips meet the tub surround
- Where the cement backerboard meets the greenboard
Take your time applying the caulk. Make sure you fill the gaps fully and get a nice smooth finish by wetting your finger and smoothing it out. Let the caulk cure fully before moving on.
Step 9: Grout and Seal the Tile
Once the caulk has dried, you can grout between the tiles and transition strips. Make sure to apply grout sealer after to waterproof it.
After grouting, run a bead of 100% silicone caulk around the bottom where the tiles meet the tub surround. Tool the caulk with a wet finger for a smooth finish.
Let the entire area cure for at least 48 hours before using your shower to allow everything to fully dry and set.
Step 10 (Optional): Install Decorative Trim
For a really professional, built-in look you can install trim pieces where the surround meets the wall. Adhere them with silicone caulk and fill any gaps or imperfections.
This decorative trim hides any flaws in the drywall and gives your bathroom a stylish, high-end look. Take your time lining up the trim pieces for the best results.
Decorative trim adds a professional finish around the shower
Step 11: Paint the Walls
The final step is to paint the greenboard walls around the enclosure. Use a high-quality bathroom paint designed for humid environments.
Apply at least two coats, allowing the first coat to fully dry before adding the second. Painting hides drywall imperfections and makes your shower area look seamless.
If needed, caulk where the walls meet the tile trim prior to painting for a flawless look. And that‘s it, your shower is now fully sealed and waterproofed for the long haul!
Tips for Success
Here are a few quick pro tips to ensure your drywall seals successfully:
- Always start with moisture-resistant backerboard or greenboard
- Properly tape and mud seams between panels
- Apply 2-3 coats of waterproofing membrane
- Caulk every single seam and gap thoroughly
- Use quality 100% silicone caulk near water sources
- Grout and seal the grout once it has cured
- Consider decorative trim for a polished look
- Use bathroom paint with mold inhibitors
Take your time and don‘t skip any steps. The small effort is well worth it to avoid leaks, damage, and mold down the road. I hope these tips help you achieve professional, watertight results around your shower! Let me know if you have any other questions.
