Set out from the finished tile line, not the structural floor. Establish the drain position against the wall, confirm the outlet route, verify the build-up at the drain location, then check the grate will sit flush before any cutting begins.
Setting-out sequence
| Step | What to establish |
|---|---|
| 1. Datum | Establish the finished tile level in the room — mark it on the walls |
| 2. Position | Mark the channel centreline and the wall line offset |
| 3. Build-up | Measure slab-to-finished-tile depth at the drain position |
| 4. Outlet route | Confirm pipe direction, fall and available depth |
| 5. Frame height | Check the drain’s adjustment range covers the tile thickness |
| 6. Openings | Only now cut the floor opening and prepare supports |
Common setting-out errors
- Working from the screed level — the drain ends up below or above the tile.
- Measuring build-up away from the drain — screed depth varies across a room.
- Not checking the outlet first — discovering a joist or service in the pipe route after opening the floor.
- Assuming the wall is straight — a wall-to-wall drain needs the opening width measured at finish, not from the drawing.
- Cutting before confirming frame height — the tile may not fit the adjustment range.
Practical notes
- Mark the finished tile level in more than one place — floors are rarely perfectly level.
- For wall-to-wall drains, allow a small tolerance at each end for setting and cutting.
- Confirm the outlet route before opening the floor — this is the single most common cause of site delay.
- Protect the grate from the moment it is unpacked.
Related: installation sequence · common installation mistakes