A bath leak is one of the harder bathroom failures to find without proper access. The bath sits inside a panel, the trap and overflow are buried in a dark void, and water can weep from the rim seal, the waste, the overflow gasket, the tap tails, or the flexible hoses behind the panel. The result is a stain that drifts along a joist and drops into the ceiling void 1 to 2 metres from the bath itself. The only way to be certain is to remove the panel, light the underside, fill and test the bath in normal use, and watch the void in real time as the leak develops.
Our team treat a bath leak test as a structured fill-and-test investigation. We remove the bath panel cleanly so it can be refitted, light the void with inspection lamps, then run the bath through three discrete states: rim-only spray, full fill to the overflow, and timed drain. Protimeter Surveymaster readings on the surrounding floor, a FLIR E76 or E96 thermal camera aimed at the void and the ceiling below, and a tissue-tracing pass against every visible joint separate a slow weep from a catastrophic overflow gasket failure, and pinpoint the failing component within the same visit. Where a weep is too slow to see by eye, fluorescent UV dye testing can be used to trace the exact path.
Where this service applies
- Ceiling stains directly below a bath, especially after a long soak
- Warped floorboards on the long side of a panelled bath
- Slow weeps that only show when the bath is filled high
- Dump leaks suggesting overflow-gasket or waste failure
- Acrylic baths that flex, breaking the silicone seal at the wall
- Leasehold flats where the neighbour reports water after baths
- Recurring damp at the base of bath panels resealed before
- Pre-purchase surveys where the bath is suspected of historic damage
How we deliver
No surprises, no upselling. The exact path every job follows.
- 1
Dry baseline and symptom review
Protimeter readings on the floor, the wall at skirting level, and the ceiling below give a dry reference. We log when symptoms appeared and what bath usage triggers them. - 2
Bath panel removal
We remove the front panel, and end panel where fitted, working carefully around silicone, magnetic catches, and concealed brackets so it can be reinstated without damage. - 3
Under-bath visual and dry test
Inspection lamp into the void, tissue laid against the waste, overflow elbow, supply tails, and flexible hoses. Any pre-existing damp is photographed before water is run. - 4
Rim-only spray test
We spray the rim seal, tap escutcheons, and silicone bead with the shower head, watching the void for any change. This isolates seal failures from waste failures before water enters the bath body. - 5
Full fill to overflow
The bath is filled to within 25mm of the overflow and left to stand for 10 to 15 minutes. We monitor with the FLIR camera and tissue tracing, which catches slow seals that only fail at depth. - 6
Timed drain test
The bath is drained and the waste run observed for dump leaks at the trap, compression nut, or soil-stack boss. Overflow gasket failures usually show clearly during drain, when water passes the overflow elbow under flow. - 7
Findings, report, and panel reinstatement
We mark the failing component, quote the repair separately from the diagnostic, refit the panel, and issue an insurance-grade report with thermal frames and moisture readings.