By Simon Beames, The British Remodeler — 26 years tiling, Schluter-certified, working to TCNA standards in Colorado Springs.
What a shower pan actually does
Tile and grout are not waterproof. They never have been. Water passes through grout joints every single shower — that is normal, and it is expected. What keeps that water from ending up in your subfloor is the pan underneath: a sloped, waterproof base that catches the water and walks it to the drain. If the pan is wrong, everything above it is decoration on a slow leak.
How a proper concrete pan is built
- Pre-slope first. A mud bed sloped a quarter-inch per foot toward the drain goes down before the liner, so water that reaches the liner is already travelling the right way — not pooling on a flat liner, which is where most DIY pans fail.
- The liner. A heavy PVC liner, folded (never cut) at the corners, run up the walls well above the curb, and clamped properly at the drain.
- The mud bed. A second bed of deck mud over the liner sets the final slope your tile sits on — firm, dense, and true.
- Waterproofed walls. The walls get their own waterproofing, tied into the pan, so the whole wet area works as one system.
- A flood test. The pan is plugged and filled, and it sits. If it holds water overnight, it will hold it for decades.
Concrete pan or prefab base?
A prefab acrylic or fibreglass base has its place — standard sizes, quick installs, tight budgets. But a concrete pan is built to your shower: any size, any drain position, a proper bench or a curbless entry if that is what the room wants. It feels solid underfoot because it is, and when it is built right it will outlast the tile on top of it. For an odd-shaped Colorado Springs bathroom — and half the ones I open up are odd-shaped — there is usually only one honest answer.
The short version
You will never see your shower pan again once the tile is down. That is exactly why it has to be built by someone who treats the invisible work as the important work — because it is. Proper job, done once.