When people plan a bathroom remodel, they spend hours picking out tile, choosing a vanity, and debating between a freestanding tub and a walk-in shower. Those decisions matter. But there’s one part of a bathroom remodel that matters more than all of them combined.
Waterproofing.
It’s not sexy. It’s not visible. And most homeowners don’t think about it until it’s too late. But if your bathroom isn’t waterproofed correctly, you’re going to have problems. Leaks. Mold. Rotting subfloors. And expensive repairs that could have been avoided.
What Is Waterproofing?
Waterproofing is the process of creating a moisture barrier behind your tile and around your shower or tub. It prevents water from seeping through grout lines, getting into the walls, and causing damage. In a bathroom, water is everywhere. Showers. Sinks. Humidity. If that water gets behind your tile and into your walls, it creates the perfect environment for mold and rot. Good waterproofing stops that from happening.
Why Waterproofing Matters More Than You Think
Here’s the problem: tile and grout are not waterproof. Grout is porous. Water gets through it. That’s normal. But if there’s no waterproof barrier behind the tile, that water goes straight into your drywall or substrate. Over time, this causes mold growth, rotting studs, loose tile, and expensive leaks.
How Waterproofing Should Be Done
Cement Board + Membrane
Cement board (like Durock) is installed, then a waterproof membrane like RedGard is applied over it and sealed at all seams and corners.
Foam Backer Boards
Products like Kerdi Board or Wedi Board are waterproof foam boards that replace cement board. Seams are sealed with waterproof tape.
Liquid Membranes
Products like RedGard or AquaDefense are rolled or troweled onto cement board or drywall to create a waterproof layer.
The key is that every method requires attention to detail. Corners, seams, and transitions must be sealed correctly. One gap or missed spot can lead to water intrusion.
How to Make Sure It’s Done Right
If you’re hiring a contractor for a bathroom remodel, ask these questions:
- 1. What waterproofing method are you using?
- 2. Are you waterproofing the shower walls, shower pan, and floor?
- 3. How are you sealing corners and transitions?
- 4. Can I see photos of waterproofing on previous projects?
A good contractor will be happy to explain their process. If they brush off the question or say “we just use cement board,” that’s a red flag.
The Bottom Line
Tile and fixtures get all the attention in a bathroom remodel. But waterproofing is what makes your bathroom last. It’s the difference between a remodel that looks good for 20 years and one that fails in 5. Don’t skip it.