Why is my bathroom ceiling dripping?
Telling condensation on a cold ceiling from a genuine leak from above, and what each one requires.
- Difficulty
- beginner
- Time
- 30 min
- Read
- 3 min
Short answer
If it drips during and after showers, is worse in cold weather, and stops in summer, it is condensation on a cold ceiling — usually poor loft insulation over the bathroom plus inadequate extraction. If it drips regardless of whether the bathroom is used, it is a leak and needs finding before anything else.
The two causes look identical from below and need completely opposite responses. Ten minutes of observation separates them and saves a great deal of wasted work.
What you'll need
- A torch and loft access if there is one
- Dry paper or a bowl to measure the drip rate
- A thermometer or your hand
Step by step
- Note when it drips.Keep a note for three days. Only during and after showers means condensation. Continuous, or worse after rain, means a leak.
- Check whether the ceiling is cold.Put a hand flat on it. A ceiling noticeably colder than the walls means missing or compressed loft insulation above, which makes it the condensing surface in the room.
- Look in the loft directly above.Look for missing insulation over the bathroom, an extractor duct terminating in the loft, damp timbers, a leaking tank, or a wet patch on the underside of the felt.
- Check where the extractor duct goes.A duct dumping into the loft puts every shower's moisture straight onto the cold roof structure, and it comes back through the ceiling. This is extremely common.
- Rule out a plumbing leak from above.If there is a bathroom or a pipe run above, run each fitting in turn and watch. A leak from a shower tray upstairs is a classic and looks exactly like condensation at first.
- Check the roof if the drip follows rain.A slipped tile or a failed flashing shows up as drips hours after rain rather than after showers. That timing is the giveaway.
- Fix the insulation for a condensation case.Top up the loft insulation over the bathroom to full depth, taking care not to block eaves ventilation. A warmer ceiling stops condensing.
- Fix the extraction as well.Insulation alone is not enough if the moisture is not being removed. The two go together.
- Ventilate the loft.A loft with blocked eaves and a bathroom below can stay damp all winter. Check the eaves vents are clear.
- Deal with the decoration last.Repainting a ceiling before the cause is fixed simply repeats the problem, and paint over a damp surface fails quickly.
Tips
- Keep a three-day log of when it drips. It is the fastest way to separate condensation from a leak.
- A duct terminating in the loft causes both loft condensation and a dripping bathroom ceiling. Check it before anything else.
- Never assume it must be the roof. Bathroom ceilings drip from condensation far more often than from leaks.
Common mistakes
- Repainting the ceiling to fix it — Paint does not change a surface temperature or remove moisture. It peels within a season, and the time spent hides the problem for a few months.
- Sealing the ceiling with an impermeable coating — It traps moisture in the plaster and the void above, so the damage carries on out of sight and the plaster eventually fails.
If it doesn't work
Drips during and after showers only
Cause: Condensation on a cold ceiling — Fix: Top up loft insulation over the bathroom and improve extraction.
Drips continuously, unrelated to use
Cause: Plumbing leak or roof leak — Fix: Find the source in the loft or the room above before doing anything else.
Drips hours after rain
Cause: Roof defect — Fix: Get the roof checked — slipped tile, failed flashing or a blocked valley.
Whole loft damp and timbers wet
Cause: Extractor duct terminating in the loft — Fix: Duct it outside properly and let the loft dry.
Questions people ask
Can condensation really drip like a leak?
Yes. A cold ceiling above a shower can collect enough water to form and release drops, and it can be surprisingly heavy in cold weather. The timing is what distinguishes it.
Will more insulation alone solve it?
It helps a great deal by raising the ceiling temperature, but if the moisture is not being extracted it will simply condense somewhere else. Both need attention.