Your tile isn't what keeps your shower dry
Tile and grout are the finish, not the barrier. A shower stays dry because the floor underneath is sloped to the drain and the walls and floor of the wet area are covered in a continuous waterproofing membrane before any tile goes on.
Most people judge a shower by the tile. It is the part you see every morning, so it makes sense. But tile is the last layer, and it is not the one keeping water out of your walls.
Grout is porous. Water soaks into it every time you shower, and some of it gets through. What happens to that water next is decided by two things you will never see again once the job is done.
1. The floor is sloped to the drain
Under the tile, the shower floor should fall toward the drain from every side. Water that gets through the grout runs down to the drain instead of sitting under your tile. A flat floor holds water, and water that sits eventually finds a way out.
On a curbless shower, the slope matters even more. There is no curb to stop water, so the floor has to be recessed and sloped so it all goes to the drain and not across your bathroom.
2. The walls and floor are waterproofed
Over the board and under the tile, the whole wet area gets a waterproofing membrane. On my jobs it is red, so you can see at a glance that it covers every wall, the floor, the corners and the seams.
This is the layer that actually keeps your house dry. The tile protects the membrane and makes it look good. The membrane protects the house.
Why you should ask to see it
Once the tile is on, nobody can tell you what is underneath. Not you, not a home inspector, not the next buyer. That is exactly why it is worth asking to see it while it is still open.
A contractor who did it right will be glad to show you. It is the part of the job we are most proud of, and the part nobody gets to admire.
Three questions to ask before the tile goes up
- Is the floor sloped to the drain?
- What waterproofing goes on the walls and floor?
- Can I see it before you tile?
If the answer to the last one is no, ask why.
Frequently asked questions
Is grout waterproof?
No. Grout is porous and lets some water through. The waterproofing membrane behind the tile is what stops water from reaching your walls and subfloor.
What is the red layer in a shower?
On DNU jobs, the red layer is the waterproofing membrane, applied over the walls and floor of the wet area before tile.
Should a shower floor be sloped?
Yes. The floor under the tile should fall toward the drain so water that gets through the grout drains away instead of sitting under the tile.
Let me look at your room.
Book a free consultation. I will walk you through what it takes and give you a detailed quote.