A ceiling stain is a message from somewhere above. Before you cut a hole or call anyone, work out what kind of water it is. Where the stain is, when it appears and what is above it usually answer the question in a few minutes.
Look at what is above
- A bathroom or laundry room above: plumbing is the likely cause. Toilets, tubs, showers and washing machines are the usual suspects.
- Only attic above: the roof, a plumbing vent pipe where it passes through the roof, or condensation on ductwork or a bathroom fan duct.
- A pipe run you know about, such as the main line to an upstairs bathroom or a radiator pipe: that pipe.
Look at when it appears
- Only during or after rain, and it dries out in between: the roof, flashing, or a gutter overflowing into the wall.
- After someone showers or the washing machine runs: a fixture or its drain.
- Steadily, whatever the weather: a supply pipe, which leaks all the time because it is under pressure, or a slow toilet leak.
- In cold weather, without rain: condensation on a cold pipe or duct, or an ice dam at the eaves.
Test it
Put a bucket under the drip, and dry the stain's edge with a hair dryer so you can see if it spreads. Then run the fixtures above one at a time for several minutes each: the shower, then the tub, then flush the toilet several times, then the sink. Wait a few minutes after each. A drip that starts after the shower points to the shower drain, the tile or the door seal. One that starts after several flushes points to the toilet's wax ring. If nothing happens with any fixture, and it is not raining, suspect a supply pipe.
A bulging ceiling
Water collecting above drywall makes a sag or a bubble. Put a bucket underneath and push a screwdriver through the lowest point to let it drain in a controlled way. Otherwise it will come down on its own, and take more of the ceiling with it.
The usual plumbing causes, by fixture
- Toilet: a failed wax ring. The stain is under the toilet, and the toilet often rocks. It has to be lifted and resealed.
- Shower or tub: the drain fitting, failed grout or caulk where the tile meets the tub, or the shower door. Caulk and grout are homeowner jobs; a drain fitting is a plumber's.
- Washing machine: the drain hose jumping out of the standpipe, or a supply hose. Replace the hoses if they are old.
- Supply pipe: a pinhole in copper, a failed joint, or a pipe that froze. Close the main valve and call a plumber.
- Radiator or heating pipe: a valve packing or a joint. Close the radiator's valve if it has one.
What to do once you know
For plumbing, stop the water at the fixture or the main, fix or replace the part, and let the ceiling dry fully before repairing it. A stain that keeps growing after the fix means there is a second leak or the first was not the cause. For the roof, a roofer. For condensation, insulation on the pipe or duct.
When to call a plumber
- A supply pipe leak
- A toilet that needs lifting, if that is beyond you
- A shower drain fitting
- A leak you have tested for and cannot find
Find a licensed plumber near your town.