Start with what you can see
Common flat roof problems
A flat roof tells you it is in trouble long before it pours through the ceiling, if you know what to look for. Find the sign that matches yours, learn how urgent it is and what to do before a roofer arrives.
What are you seeing?
Standing water (ponding)
Puddles that are still there a day or two after rain.
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Blisters
Raised bubbles in the membrane that move or crackle when pressed.
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Cracks and alligatoring
A surface that looks dry, split or like reptile skin.
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Open seams
Edges lifting, tape peeling or a visible gap between sheets.
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Flashing leaks
Water entering at walls, chimneys, vents or curbs.
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Clogged drains
Slow or blocked drains, scuppers and downspouts.
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Ice and snow damage
Ice dams, heavy snow load, freeze–thaw splits.
View detailsCeiling water stains
Brown rings, bubbling paint or drips inside.
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Wind damage
Lifted edges, torn membrane, displaced gravel after a storm.
View detailsSigns rarely come alone
Ponding leads to clogged drains and ice, ice cracks seams, and open seams show up as ceiling stains. When a roofer fixes only the symptom you see, the cause is still there. A good repair visit looks at the whole roof: the slope, the drains, the flashings and the layers underneath.
If you have a leak right now, read finding a flat roof leak before you start climbing around. To judge whether a repair makes sense or the roof is at the end of its life, see repair or replace.
What you can safely do yourself
Look from the ground or a window
Binoculars from the ground or a photo from an upstairs window show a lot. Take dated photos of anything unusual.
Contain the water indoors
Bucket under the drip, plastic sheet over furniture, a small hole in a bulging ceiling to let the water out in a controlled way.
Stay off the roof in winter
Ice, snow and frozen membranes are slippery and you can fall or damage the roof. Let a professional deal with it.
Keep a log
Note when it leaks: after rain, snowmelt, wind from one direction. That detail points straight to the cause.
Questions about flat roof problems
Which problem is the most urgent?
Active water coming inside is the one that cannot wait. Ponding and blisters can often be scheduled; a drip cannot. See emergency repairs.
How do I know if I need a repair or a new roof?
A few local problems on a roof that is otherwise sound point to repair. Widespread cracking, wet insulation and repeat leaks point to replacement. An inspection gives you a clear answer.
Can a flat roof problem be fixed in winter?
Temporary protection usually can. Permanent repairs normally need dry, reasonably mild conditions for adhesives and seams to bond.
Leak, damage or an old flat roof?
Send a few details and photos. We reply by email with next steps and a written quote.