A curbless (walk-in, level-entry) shower reads as a single, continuous wet floor — no step, no threshold. That openness is exactly what makes it unforgiving: every drop of water must be guided to the drain by slope alone. Get the tray, the fall and the waterproofing right and it is beautiful and safe. Get them wrong and water pools at the doorway.
What a curbless tray actually does
A purpose-made XPS shower tray is a pre-sloped, tile-ready panel. The slope is moulded into the factory foam, so the installer is laying a finished gradient rather than trowelling screed by eye. TANYTE trays ship in 30–50 mm build-up with a continuous waterproof skin, ready to receive thin-set and tile directly.
- Curbless / walk-in: zero threshold, fully accessible, the modern spec for hotels and care homes.
- Linear-drain trays: one long channel, single gentle fall — easiest to tile and to keep clean.
- Center-drain trays: four-way fall, classic look, needs a little more planning around the outlet.
Slope: the number that decides success
Most codes ask for a minimum fall of about 1:50 (2%). In practice a 1:50 to 1:80 gradient moves water without feeling like a ramp. Two rules matter more than the exact percentage:
- One direction per plane. A single, uninterrupted fall to the drain beats a "bowl" that leaves a ring of standing water at the edges.
- No flat zones. The last 100 mm before the drain and the approach from the room must both be on the fall.
Linear vs center drain
| Factor | Linear drain | Center drain |
|---|---|---|
| Tiling | One fall direction, large format friendly | Four-way fall, more cutting |
| Accessibility | Best for level entry | Good, needs careful edge fall |
| Hair / debris | Long channel, easy sweep | Central point, grate trap |
| Best use | Walk-in, wet rooms, large formats | Compact stalls, classic look |
Waterproofing the tray and the room as one plane
The tray is already waterproof, but the room around it is not. Treat the whole wet area as a single tanking plane:
- Set the tray on a tile backer board or sealed substrate; do not bed it in wet adhesive that can trap moisture.
- Overlap the tray's bonded flange with the wall membrane and niche using a continuous liquid or tape system.
- Carry the waterproof layer at least 100 mm up the walls (or to splashing height) and seal every penetratio — grab bar, mixer, spout.
Common failures to avoid
- Doorway pool: the approach tile is flat. Extend the fall a full stride into the room.
- Drain too high: the outlet sits proud of the tray. Dry-fit and check before tiling.
- Sealed, not tanked: grout is not waterproofing. The membrane beneath does the work.
Frequently asked questions
Can a curbless tray go on a timber floor?
Yes, but the floor must be stiff and the tray fully supported. Use a decoupling layer and screw-fix the surrounding backer board to the joists so there is no movement under the gradient.
How much height does it add?
Typically 30–50 mm of tray plus tile and adhesive — far less than a traditional screeded wet-room floor, which is why it suits renovations.
Is a linear drain harder to waterproof?
No. A single channel with a bonded flange is often simpler than a center outlet because there is one clear fall direction and fewer corners to seal.
Do I need a pre-slope under a pre-sloped tray?
No. The tray is the pre-slope. You only need a flat, sound, dry substrate to set it on.
Can I use large-format tiles?
Linear-drain trays suit large formats well because the single fall means fewer cuts and a cleaner grid.
Specify a tray that is already on the fall
TANYTE supplies pre-sloped, tile-ready XPS curbless trays, niches and waterproofing accessories in OEM/ODM volumes for distributors and contractors.