If the ceiling is bulging
A bulge in the plasterboard means water is sitting on top of it, and waterlogged plaster can give way. Keep people and pets out of that room, switch off power at the switchboard if water is near a light fitting, and put a bucket under the lowest point. Call a roofer or plumber, or the SES on 132 500 if it's storm damage that can't wait.
Is it the roof, or something else?
| Points to the roof | Points somewhere else | |
|---|---|---|
| When it shows up | During or just after rain | In dry weather, or while a tap or shower is running |
| Where it is | Top-floor rooms, often near walls, chimneys, skylights or under a valley | Under a bathroom, laundry, hot water service or air conditioner |
| What it looks like | Brown rings that grow after each storm | Even dampness or speckled mould over a wide area, often on cold mornings |
| Who to call | A roofer | A plumber, or better ventilation if it's condensation |
Condensation is the one people miss. Insulation maker CSR Bradford says it mostly happens in winter, when warm, moist air from the house meets the cold underside of the roof. If your marks appear on chilly mornings with no rain, read our guide on condensation or a leak before you call anyone.
In what order should the repairs happen?
Stop the water. A roofer fixes the roof, or a plumber fixes the pipe. Patching the ceiling before that just means patching it twice.
Let it dry. Wet plasterboard and insulation need time to dry out properly. Insulation that got soaked may need replacing, so ask the roofer to check it while they're in the roof space.
Check for mould. A ceiling that stayed wet for a while can grow mould on the back. If you can smell it or see it spreading, it needs cleaning or replacing, not a coat of paint.
Fix the ceiling. A light stain can be sealed with a stain-blocking primer and repainted. Soft, sagging or crumbling plasterboard gets cut out and replaced by a plasterer, then painted.
What you can do, and what to hand over
You can
- Catch drips and move furniture, rugs and electronics out of the way
- Note whether it appears with rain, with the shower running, or on cold mornings
- On a dry day, run the upstairs shower or bath for a while and watch the ceiling below
- Once the source is fixed and the plaster is dry, seal a small stain with stain-blocking primer and repaint
Leave to a roofer
- Finding and fixing a roof leak above the ceiling
- Checking the roof space for wet insulation and timber
- Telling you what got wet up there, so the plasterer knows what to replace
If it were our ceiling
We'd leave the ceiling alone until the cause is fixed and the plaster is properly dry. Get the roofer or plumber to show you what was wrong, then get the ceiling quoted once you know it won't get wet again. Fresh paint over a live leak only hides the stain until the next rain.
Want a roofer to take a look?
Tell us the job and your postcode. We match it with a Find My Roofer certified roofer who specialises in that kind of work, and they call you to quote. Your number goes to them alone.
