Quick answer
Find the source first, stop the water, then fix the actual cause — don’t just paint over the damp. Most bathroom leaks come from failed silicone or grout, a worn shower tray or bath seal, or loose tiles letting water behind them. Resealing buys time, but if damp keeps returning the waterproofing has failed and needs putting right properly, or the damage spreads to floors, ceilings and the room below.
Where bathroom leaks usually come from
Tracking a leak is half the battle, because water travels — the damp patch is often nowhere near the source. These are the usual culprits, roughly from most to least common, and knowing them helps you describe the problem accurately when you call.
Failed silicone or sealant
The seal where the bath, tray or basin meets the wall or floor perishes and lets water creep behind. The most common leak, and the one resealing genuinely fixes — if that’s truly all it is.
Cracked or missing grout
Grout that’s cracked, crumbling or missing lets water through the tile joints to the wall behind. A surface fix rarely lasts if the movement causing it isn’t addressed.
A worn shower tray or bath seal
Movement under a tray or bath breaks the seal as you stand in it. Often shows as a damp patch on the ceiling below rather than in the bathroom.
Pipework or waste joints
A weeping pipe or waste connection behind the wall or under the floor — harder to find, and usually needs panels or tiles off to reach.
Persistent damp without an obvious leak can also be condensation from poor ventilation — see whether you need a better extractor fan.
What to do right now
If you’ve got an active leak or spreading damp, a few sensible steps limit the damage before anyone gets to you:
- Stop using the bath or shower that seems to be the source
- Mop up standing water and dry the area to slow the spread
- Check the ceiling in the room below for stains or bulging
- If a ceiling is sagging or bulging, keep clear — that’s trapped water
- Isolate water to a fitting if you can find the stop valve
- Take photos of the damp for your fitter and, if needed, insurer
Then get it looked at properly. A damp bathroom rarely fixes itself, and the longer water sits, the more it rots timber, lifts tiles and damages the room below.
Water travels — the damp patch is often far from the leak, so finding the true source matters.
Fixing the cause, not just the symptom
The temptation with a leak is to run a fresh bead of silicone and hope. Sometimes that’s genuinely the fix — a single perished seal. But if you’ve resealed before and the damp came back, the silicone was never the real problem. Behind a recurring leak there’s usually movement, a failed tray, or waterproofing that’s broken down — and those need the tiles or panel off to put right. Patching over it just hides the damage while timber and plaster quietly rot.
This is exactly when a damp bathroom tips from a repair into one of the signs you need a new bathroom. If the waterproofing has failed across the room, a proper renovation with fresh tanking is often more economical than chasing leak after leak. Either way, we find the source and fix the cause.
Common questions about leaks and damp
Why does my bathroom keep getting damp even though I clean it?
Is a stained ceiling below the bathroom always a leak?
Will I need a whole new bathroom to fix a leak?
Can damp be condensation rather than a leak?
Catch it early, fix it once
Got a leak or damp you can’t shift?
We’ll find the source, fix the cause and give you a fixed written quote — before a small leak becomes a big repair. Plymouth and the South West.