If your shower is leaking through the ceiling, stop using the shower, turn off the water to it if the leak continues when it is off, and keep electrics away from the wet area below. Then the source is traced step by step. In most homes it is one of five things: failed sealant around the tray or bath, a tray that has moved, a loose or perished waste, cracked grout letting water behind the tiles, or a leak on the supply pipework. Only once the source is fixed and everything has dried out is the ceiling below repaired.
First steps when water comes through
Act quickly to limit the damage, then work out whether the leak only happens when the shower runs.
- Stop using the shower and the bath on that floor
- If water keeps dripping with the shower off, turn off the supply
- Keep away from light fittings and switches near the wet area
- Put down towels and a bucket, and move furniture clear
- If the ceiling is bulging, do not poke it; call for help
- Take photos of the stain and the bathroom for your records
Tracing the leak: seals and tray
A leak that only appears when someone showers usually comes from the shower area itself rather than the pipes. The sealant between the tray and the walls is the first suspect. If it has lifted, split or gone mouldy, water runs behind it and into the floor. The mouldy shower sealant guide covers how that joint is renewed properly.
A tray that moves underfoot is the next suspect. If it was not bedded on a firm, level base, it flexes every time someone stands on it, which breaks the seal and can loosen the waste. Pressing around the edges of the tray will show any movement.
Waste, grout and tiles
The waste under the tray can leak at its seal or where it joins the pipe. A simple test is to run water straight down the drain without wetting the walls. If the ceiling shows signs of water, the waste is the likely culprit.
Grout lets water through once it cracks or crumbles. The water soaks behind the tiles and runs down to the tray edge and the floor below. Tapping tiles for a hollow sound shows where the adhesive has failed. The regrout or retile guide explains how to tell whether grout alone is the problem.
Supply pipework
If the stain grows even when nobody has used the shower, a supply pipe or a joint behind the valve may be leaking. This kind of leak is constant rather than linked to use, and it often needs a panel or tile removing to reach. Pipework repairs beyond simple connections are best handled by a plumber, and the handyman or specialist guide explains where that line usually sits.
Making good the ceiling below
Once the leak is fixed, the ceiling must dry fully before it is repaired. Plasterboard that has been soaked often sags and loses strength, and it is usually replaced rather than patched. Small stains on a sound ceiling can be sealed with a stain blocking primer and repainted.
Ceiling repairs fall under general building work: cutting out damaged board, fixing new board to the joists, filling and finishing ready for decoration. Getting the bathroom above sorted first is essential, otherwise the new ceiling will stain again.
Repair or refit the shower
A single failed seal or a loose waste is a repair. Where water has been getting behind tiles for some time, the boards behind them may be soft, and patching tends to fail again. In that case a planned shower or bathroom refit, with proper backer board and tanking, is the lasting fix. The bathroom renovations and general building services cover both the bathroom above and the ceiling below, so the whole job can be handled by one tradesman.
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