Standing water on a flat roof is a warning, not just an eyesore. Here are the usual reasons it collects, what we check, and when a repair is enough.
If puddles sit on your porch, garage or extension roof long after the rain has stopped, something is holding the water back. Flat roofs on the modern estates around Bradley Stoke are often small, low and out of sight, so ponding can go unnoticed until a stain shows indoors. It is worth sorting before it does harm.
Falls that are too shallow
A flat roof is not meant to be level. It needs a gentle slope, called a fall, to carry water to an outlet or gutter. If the fall was never quite right, or the structure has settled, water finds the low spot and stays. This is common on additions built to a tight budget.
A deck that has sagged
Wet or weak boards sink under the covering and create a dip. We press and inspect for soft areas, because a sagging deck means moisture has been getting in for some time. Laying new covering over it only hides the issue. The damaged boards have to come out first.
A dip that returns after patching usually points back to the structure rather than the covering. In that case we open the area up, check the joists beneath for damp or rot, and replace what has gone before any new covering is laid over it.
- Soft or springy areas underfoot from inside the room
- Stains on the ceiling beneath the dip
- Dark, stretched or blistered covering over the low spot
- Moss or algae growing in one patch
Blocked outlets and gutters
Leaves and debris easily clog an outlet or the gutter at the roof's edge, and the water backs up. This is a simple fault but can be misleading, since it looks like a fall problem. From the ground you can see whether a gutter is overflowing. Clearing it from height is a job for us.
On porches and small garage roofs a single blocked outlet is often the whole cause, and once it is cleared and the roof checked over, the water drains away as it should. If it keeps blocking, we can look at fitting a guard.
What we do about it
We find out whether the cause is blockage, falls or structure. A blocked outlet is a quick fix. A shallow patch of ponding on a sound roof may be left alone or corrected with a local repair. Widespread ponding with damaged boards usually needs the roof stripped and re-laid with the falls corrected.
Keeping it from coming back
Once the roof is right, keep the outlets clear and have the roof looked over each year. Check the ceiling below for fresh stains. Call us if water still sits a day or two after rain. Some falls corrections may need planning or Building Regulations checks, and we advise before work starts.
Frequently Asked Questions
Is a little standing water after rain normal?
A shallow film that dries in a short time is not unusual on some roofs. Deep puddles that hang around, or a patch that gets worse, tell us the falls or deck need looking at. When in doubt, ask us to check.
Will ponding damage the roof?
Yes, over time. Standing water speeds up wear on the covering, collects dirt and can find its way through seams and edges. It also adds weight to a roof that may already be weak, so it is better to deal with early.
Can ponding be fixed without a new roof?
Where the roof is otherwise sound, sometimes. A cleared outlet or local repair can be enough. If the deck is rotten or the falls are wrong across the whole roof, a full replacement is the honest answer.
Talk to our team about flat roofing in Bradley Stoke
Every roof is different — the fastest way to get an accurate answer is a quick chat with our team.