How to Remove Mold From a Shower (DIY Step-by-Step Guide)

If you need to remove mold from a shower, especially mold hiding behind tile, you’re not alone. When we renovated our small bathroom, I discovered moisture damage and mold behind the old tile surround – the kind you only notice once demo starts.

With research, patience, and the help of my contractor father-in-law, I learned how to safely remove shower mold, clean the framing, rebuild the walls properly, and fully waterproof the space so it’s ready for tile. And honestly? It’s far less intimidating than it looks.

This guide shows you exactly how I removed mold from the shower and rebuilt everything the right way.

Time: Multi-day project (demo, drying, rebuild, waterproofing)
Difficulty: Advanced DIY / confident intermediate (demo + framing + waterproofing)

If your shower is already waterproofed and you’re ready for the pretty part, head to: How to Tile a Shower Wall (Even If You’ve Never Done It Before).

For a recap of this entire project, see my blog post on a DIY Small Bathroom Remodel on a Budget.

How to Remove Mold From a Shower: At a Glance

Here’s the big-picture overview before we get into the photos and steps:

• Set up basic containment and safety gear (gloves, N95, goggles).
• Demo the tile and remove wet greenboard or damaged drywall.
• Clean, treat, and fully dry the wall framing.
• Frame and pitch a shower niche if you’re adding one.
• Install ½” cement board and add blocking anywhere the walls flex.
• Tape seams with alkali-resistant mesh and thinset.
• Roll on two full coats of shower waterproofing membrane over the surround.
• Do final checks so the shower is ready for tile.

Before: What the Shower Looked Like

The original surround had:

• Stained, discolored tile
• Grout that was cracking and lifting
• Caulk separating from the tub
• Obvious moisture behind the walls

This wasn’t a “clean it with bleach” kind of mold situation. It was a demo and rebuild correctly situation – which is the right approach for long-term durability.

Below is the full process I followed to get rid of mold in a shower and prep it for tile.

Tools You’ll Need to Remove Mold From a Shower

A quick list of the essential tools:

• Safety glasses
• Gloves + N95 or respirator
• Utility knife, pry bar, hammer
• Oscillating multi-tool (super helpful but optional)
• Tape measure + level (laser level helps)
• Drill/driver with cement board bit
• Buckets, scrub brush, sponges, rags
• Paint roller + brush for waterproofing membrane

Materials You’ll Need

• Plastic sheeting + painter’s tape (basic containment)
• Mold cleaner and white vinegar
• 1/2 inch cement board + cement board screws
• Yellow alkali-resistant mesh tape for seams
• Liquid waterproofing membrane + seam fabric
• 2×4 lumber for niche framing
• Plumbing valve and trim kit (I used the sponsored Karci Pfister Faucet and loved the quality)
• Heavy-duty contractor trash bags

Step 1: Safety Prep Before You Remove Mold From a Shower

Before demo, close the bathroom door, crack a window if possible, and get some airflow going.
Wear gloves, eye protection, and an N95 respirator.

If you see widespread or unusual mold growth, consider testing or calling a remediation pro. For typical moisture-related mold behind tile, homeowners can usually handle it safely with the right precautions.

When to Call a Professional for Shower Mold

Most typical moisture-related mold behind a tub surround can be handled by a careful DIYer, but there are times when it’s safer to call a pro:

• Mold covers a very large area or several rooms.
• Anyone in your home has asthma, significant allergies, or a compromised immune system.
• The framing or subfloor is soft, rotten, or structurally damaged.
• You see mold spreading into adjacent rooms, ceilings, or under flooring.
• You’re not comfortable opening up walls, dealing with plumbing, or following a rebuild plan.

If you’re unsure, it’s always okay—and smart—to have a remediation or trusted contractor take a look before committing to a full DIY shower mold removal.

Step 2: Demo the Tile and Remove Wet Greenboard

As soon as I started removing tile, the pieces practically fell off – a clue that the greenboard behind them was saturated. Tile doesn’t detach unless moisture has been sneaking behind it for a while, which usually means mold behind the shower tile and saturated greenboard.

Everything went straight into contractor bags. This helps contain dust, debris, and mold particles so you’re not dragging them through the house.

Greenboard vs. Cement Board (What You Actually Need)

Many older bathrooms use greenboard behind showers. Greenboard is moisture-resistant… but not waterproof – and not designed for direct-water areas.

For a proper shower wall build, use:

• ½” cement board (stays stable even if wet)
• A continuous waterproofing membrane over it
• Tile on top of the membrane

Tile itself isn’t waterproof – the membrane is what protects your home.

Step 3: Clean, Treat, and Dry Shower Framing After Mold Removal

With everything open to the studs, this is where you address the mold.

Here’s the cleaning process I followed:

• Sprayed the framing with mold cleaner
• Scrubbed thoroughly
• Rinsed with warm water
• Followed up with white vinegar
• Let everything dry completely

Do not rush the drying phase. If the framing stays damp, mold can return even through new walls.

Step 4: (Optional) Build and Pitch the Shower Niche

If you’re not adding a niche, you can skip this step and move straight to cement board in Step 5.

Once everything was clean and dry, I framed the niche between studs. The pitch is crucial – a niche must tilt slightly outward so water drains and doesn’t pool against grout.

Quick Guide:

• Measure bottle height and choose a width that aligns with your tile layout
• Cut 2×4s for top, bottom, and sides
• Install bottom piece first, then top
• Shim the bottom 2×4 forward about 1-2°
• Add corner blocking so cement board edges have support

Step 5: Install ½” Cement Board (The Right Substrate)

I dry-fit all boards first to plan seams and confirm openings for the niche, window, and plumbing.

When installing:

• Screw every 7–8 inches into studs
• Keep factory edges together for straighter seams
• Leave a small gap above the tub flange (manufacturer-recommended)
• Cut clean openings for fixtures
• Map seams before committing

After all panels were up, I checked for any areas that flexed – those spots need extra blocking.

Step 6: Add Extra Blocking Where the Walls Flex

Old walls aren’t always framed perfectly. If seams don’t land on studs, cement board can flex – which causes tile lippage and cracked grout.

Here’s how I added blocking without removing panels:

• Marked any flexy seam
• Slid short 2×4 blocks behind the wall through the niche or window
• Screwed through the cement board into the block
• Sistered studs where needed
• Added blocks at corners for strength

Once blocked, the wall felt solid – exactly what you want before tile.

Step 7: Tape Seams with Alkali-Resistant Mesh + Thinset

Use alkali-resistant tape only.
Drywall tape will not work in a shower.

Apply:

• Mesh tape over seams
• Thinset to embed the tape
• A light coat of thinset over screw heads
• Tape inside niche corners carefully

Let this dry completely.

Step 8: Waterproof the Shower (Two Full Coats)

This step protects everything behind the tile.

Here’s the process:

• Roll on the first coat of waterproofing membrane
• Embed fabric where required
• Pay special attention to the niche, corners, and window
• Allow full dry time
• Apply a second complete coat

I coated everything, not just seams, so the surround became a continuous waterproof shell.

Step 9: Final Checks Before Tiling

Look for:

• Thin spots
• Missed corners
• Uneven coverage

Once the membrane fully cures, the shower is officially ready for tile.

Next step: How to Tile a Shower Wall (Even If You’ve Never Done It Before)

Why Showers Develop Mold (and How to Prevent It)

Most shower mold prevention comes down to waterproofing correctly during the rebuild and then helping the shower dry out between uses.

Most shower mold forms because of:

• Cracked grout and missing caulk let water behind the tile, which is why you often see mold in shower grout first.
• Caulk failures
• No waterproofing behind tile
• Poorly built niches
• Using greenboard instead of cement board
• Excess humidity + slow drying

With proper rebuild methods, the shower becomes far more durable.

Black Mold in Showers: What to Know

If you’re dealing with black mold in a shower-or mold that looks gray or green-the solution for a failing surround is the same: open the wall, remove wet materials, and rebuild the shower with cement board and a continuous waterproofing membrane.

• Color alone doesn’t confirm toxicity
• Never mix chemicals like bleach + vinegar
• If contamination is widespread, consider professional remediation

Pink Mold in Showers

• This is usually a harmless biofilm that thrives on soap residue.
• Cleaning and better drying habits typically keep it under control.

Pro Tips for the Best Results

• Let framing dry fully
• Use cement board in wet zones
• Always use alkali-resistant mesh tape
• Apply two full coats of membrane
• Pitch niche shelves slightly
• Use silicone, not grout, at inside corners

Common Mistakes to Avoid

• Leaving damp framing behind walls
• Skipping blocking behind seams
• Using the wrong type of tape
• Waterproofing only the seams
• Ignoring niche corners

Troubleshooting

• Musty smell after demo: Keep fans running and check adjacent walls
• Soft studs: Replace before you install cement board
• Streaky membrane: Add another coat after the recoat window

You Did It!

If you followed these steps, you’ve successfully removed mold from your shower, completed a full shower mold removal, and rebuilt with proper waterproofing.

Your next step: How to Tile a Shower Wall (even if you’ve never tiled before).

📌 Pinterest: Save This Project for Later

Pin now and come back when you’re tackling shower mold and prep.