The sign you can see from inside
Ceiling water stains
A stain on the ceiling is the end of a long journey. Water usually travels well away from where it got in. The stain tells you something is wrong, not exactly where.
- Act on it
- Source is rarely directly above
- Document before repairing
What stains look like
A fresh leak shows as a damp, darker patch that grows after rain. An old one is a yellow or brown ring with a faint edge that may expand each time it gets wet again. Bubbling or peeling paint, soft drywall, a musty smell or small drips at a light fixture are all signs. A black or green spot means moisture has been there a while.
The ring shape tells part of the story: several rings inside one another mean repeated wetting over months. A single new patch with a drip suggests a recent opening.
Why the stain is not where the leak is
On a flat roof, water can follow the deck, the top of insulation boards, a joist or a pipe for a long way before dripping. A stain by the window may come from a seam three metres away. A stain at the middle of the room may come from the parapet flashing, with water running along a beam.
In older Toronto houses with flat rear roofs, water frequently follows the junction between the main wall and the flat roof. A leak at the wall flashing shows up as a stain in the corner or at the outer edge of the ceiling. See flashing leaks.
What to do right now
Contain the water
Put a bucket under a drip and move furniture. Cover electronics.
Relieve a bulge
If the ceiling is bulging with water, a small hole at the lowest point lets it drain into a bucket. This prevents a larger collapse. Stand clear when you do it.
Watch the electrics
Water near light fixtures or outlets is a hazard. Switch off the circuit if water is near wiring, and call an electrician if you are unsure.
Photograph and note
Take dated photos of the stain and write down the weather at the time: rain, wind direction, snowmelt.
Call for a roof visit
Do not repaint over it yet. An unsealed stain hides the clues, and paint will not fix a leak.
How urgent is it?
Active drip
Urgent. Ask for a visit as soon as possible and mark the request urgent. Urgent leaks: mark the request as urgent and we answer those first. We do not promise a fixed arrival time.
Growing stain after each rain
High priority. Insulation is likely absorbing water, and the problem grows with each storm.
Dry old ring
Lower, but still worth a check. Old stains can be from a leak that was repaired, or from one that is only active in certain conditions.
Mould smell or soft drywall
Treat as high priority. Moisture has been present long enough to damage materials.
How the source is found
We start inside, mapping the stain and checking the attic or ceiling space if there is access. Then we check the roof above and around: the nearest seam, the closest flashing, drains and penetrations. Where it is unclear, a moisture scan or a controlled water test, wetting one area of the roof at a time, narrows it down. Read more at finding a flat roof leak.
The repair itself is covered under flat roof leak repair, and it is priced from $350 per repair.
Ceiling stain questions
Can I repaint over a ceiling stain?
Only after the source is fixed and the area is fully dry. Stain-blocking primer helps, but paint over a damp ceiling will fail and trap moisture.
Is it covered by home insurance?
That depends on your policy and the cause. Photograph everything and read your policy or ask your insurer. We cannot advise on claims.
Does a stain always mean the roof is bad?
No. Condensation, a plumbing leak or an air conditioner drain can also stain a ceiling. A roof visit sorts out which.
Leak, damage or an old flat roof?
Send a few details and photos. We reply by email with next steps and a written quote.