How do I get at the waste and trap under a shower tray?
Working out whether your tray has access at all, the three routes to a trap that is buried, and the removable-waste designs that avoid the problem entirely.
- Difficulty
- intermediate
- Time
- 1 hr
- Read
- 4 min
- Safety
- caution
Short answer
Try the top first: many shower wastes have a removable centre so the trap can be cleaned from inside the tray without touching the floor. If not, the routes are a side panel where the tray is raised, a hatch cut in the floor beside the tray on a timber floor, or a hatch in the ceiling below. On a low tray on a solid floor there may be no route at all short of lifting the tray.
A shower trap needs cleaning, and eventually a shower waste needs replacing, and a great many showers are built with no thought about how either will happen. If the tray is low and sitting on a concrete floor with tiled boxing all round, there is genuinely no way in. It is worth finding out which situation you are in before a blockage forces the question.
Safety
Do not cut into a floor to reach a shower trap without finding out what runs under it. Bathroom floors carry supply pipes, waste pipes and cables, and on an upper floor the joists themselves must not be notched or cut without knowing what you are doing — a notch in the wrong part of a joist weakens it seriously.
What you'll need
- A torch
- A pipe and cable detector, before cutting anything
- A flexible barbed drain tool
- A multi-tool or padsaw, if cutting a hatch
- A ready-made access panel or hatch frame
Step by step
- Try from inside the tray first.Lift the waste grating out. Many shower wastes, particularly modern ones, have a removable centre section or a screw-out cage that lets the trap body be cleaned from above without any access underneath. Shine a torch in — if you can see a threaded collar or a lift-out insert, this is your access and no cutting is needed.
- Clear a blockage from above before assuming you need to get underneath.Almost every slow shower is hair and soap in the top of the trap, and a flexible barbed drain tool through the waste reaches it. Removing a trap for a routine blockage is doing a hard job to avoid an easy one.
- Work out how the tray is sitting.Look at the height and the finish around it. A tray on legs with a removable side panel already has access. A tray on legs with tiled boxing all round has access behind whichever panel you are prepared to cut. A tray bedded straight on the floor has no space underneath at all.
- Take the side panel off if there is one.Where a raised tray has a plastic or tiled skirt, that skirt is the access. Look for screws behind end caps, clips, or a bead of silicone along the top edge only. If it is siliconed all round, cut the bead and take it off — then refit it so it comes off again next time.
- Consider a hatch in the floor beside the tray, on a timber floor.Detect for pipes and cables, then lift a floorboard or cut a hatch in the boarding immediately adjacent to the tray, between joists and never through one. Trim the opening with battens screwed to the joist sides so the cut piece drops back in and is supported.
- Consider a hatch in the ceiling below.Often the least destructive option, particularly with a plasterboard ceiling below. A small neat hatch with a proprietary access panel in a room where it does not matter — a cupboard, a hall, a utility — is far less work than lifting a bathroom floor. Check the ceiling void is not full of insulation and cabling first, and remember it changes the fire separation between floors in a flat, which is a reason to keep it small and properly closed.
- Accept when there is no route.A low-profile tray bedded onto a solid concrete floor, tiled boxing all round, and a solid ceiling below is a shower with no access. The trap is cleaned from above and if the waste ever fails the tray comes up. Knowing that now is better than finding out during a leak.
- Build access in whenever the tray is out.The moment to solve this permanently is when a tray is being replaced. Specify a waste with a removable insert, leave a removable side panel, and make sure the trap is reachable. It costs nothing at that stage.
Tips
- Photograph the pipework under the tray while you have access, with a rule in the shot. It answers a dozen future questions without opening anything up.
- Fit a hair catcher in the shower waste and the number of times you need to reach the trap drops to almost none.
- If you are having a wet room or a low tray installed, ask the fitter directly how the trap will be serviced. A good one has an answer ready.
Common mistakes
- Cutting a floor hatch without detecting first — Bathroom floors are full of pipes and cables, and the shower's own supplies usually run right beside the tray.
- Notching or cutting through a joist to make room — Joists carry the floor and the bathroom. Notching one in the wrong position or too deeply is a structural change, not a DIY convenience.
- Siliconing a tray side panel all the way round when refitting it — It becomes the access you have to destroy next time. Seal the top edge only.