Many of the damp patches we are called out to in winter start with something simple: a gutter full of leaves. Autumn is the best time to check your rainwater goods, before the heavy rain and before the leaves have rotted down into a solid blockage.
Why gutters matter so much
A typical roof sheds a surprising amount of water in a heavy downpour. If a gutter overflows or a downpipe fails, that water pours down the face of the wall instead of being carried away. Brickwork, render and pointing can soak it up, and it eventually shows inside as a damp patch, bubbling paint or black mould. Over time it can also lead to wet rot in timber lintels, joist ends and window frames.
What to check from the ground
- Plants, moss or grass growing out of gutters
- Green or dark streaks on the wall below a gutter joint or downpipe
- Gutters sagging, dipping or pulling away from the fascia
- Downpipes that are cracked, loose or have missing sections
- Water splashing out of gutters during rain rather than running into the downpipes
The best test: watch it rain
Put on a coat and walk around the house during a heavy shower. You will quickly see any gutter that overflows, a joint that drips or a downpipe that spills water against the wall.
Don’t forget the bottom of the downpipe
Downpipes usually discharge into a gully or drain. If the gully is blocked with leaves, water backs up and soaks the base of the wall, which can look very like rising damp. Clear gullies and check the water drains away freely.
Flat roofs, valleys and parapets
Valley gutters between roof slopes, parapet gutters behind walls and outlets on flat roofs collect leaves too, and they are harder to see. These are worth checking by a professional, as problems here often show up as damp on upper ceilings and walls.
Staying safe
Working at height is risky. If gutters can’t be reached safely from a stable, properly footed ladder, or if they are on a second storey or above, leave it to a professional.
Already seeing damp?
If a damp patch has already appeared, fixing the gutter is the first step, but the wall may need time to dry and the plaster may need repairing. Our surveyors find the cause and our property maintenance team can repair gutters, downpipes and the damage they leave behind. Read more about damp proofing.
