Here is the sentence that surprises most homeowners: tile and grout are not waterproof. Water passes through grout. It always has. A tiled shower only works because of a waterproof layer sitting behind the tile that you never see.
What a membrane actually does
A bonded waterproofing membrane — a liquid applied in coats, or a sheet bonded to the substrate — forms a continuous barrier across the shower walls and floor. Water that gets through the grout hits the membrane and drains back into the shower. Without it, that water reaches your framing and subfloor.
The systems worth having
- Schluter Kerdi — bonded sheet membrane, the most widely used system in North America
- Wedi — foam board that is waterproof through its whole thickness
- Laticrete Hydro Ban or RedGard — liquid applied membranes
Any of these done properly will outlast the tile. What matters is that a system is named on your quote and installed as a system, including the corners, the curb and the niche.
What failure looks like
It is slow, which is what makes it expensive. Water reaches the framing and nothing visible happens for two or three years. Then a tile sounds hollow. Then grout starts crumbling in one corner. Then the ceiling below stains. By the time you can see the problem, the repair is not a tile job — it is a framing job.
The flood test
We flood test every shower base before any tile goes on. The drain is plugged, the base is filled, and it sits for 24 hours. It costs a day and it is the only way to know the waterproofing holds while it is still cheap to fix. If a contractor will not flood test, ask why.
Questions to ask before you sign
- Which waterproofing system are you using? (A specific product name, not “we waterproof it”.)
- Is the shower base pre-sloped, and to what fall?
- How are the corners and the curb treated?
- Is the niche waterproofed as part of the same system?
- Will you flood test before tiling?
A contractor who answers all five confidently is a contractor worth hiring. See our full approach to shower and wet room tiling.
Get a free estimate
Ultra Renovations Inc has been installing tile across Ajax, Pickering, Whitby, Oshawa and the wider GTA for over ten years. We are a registered Ontario corporation, fully insured, and rated 5.0 on Google.
Call (647) 648-8985 or request a free estimate and we will come out, measure properly, look at your subfloor, and give you a written quote for your shower at no cost.