Damp Prevention Roofing Preston
How roof problems cause damp inside
There are two main ways a roof makes a house damp.
Water getting in
Rain gets past the roof through a slipped tile, a cracked ridge, failed flashing, a crumbling chimney or a split in a flat roof. It soaks into timbers, insulation and plaster, and shows up as stains and damp patches, often some distance from where it got in.
Moisture that can't get out
Warm, moist air from inside the house rises into the loft. If the roof space isn't ventilated, that moisture condenses on the cold underside of the roof and drips back onto the insulation and ceilings. This kind of damp is often worst in cold weather, not wet weather.
Where damp from the roof usually starts
| Where | What to look for inside | Common cause |
|---|---|---|
| Top-floor ceilings | Stains, damp patches, drips after rain | Slipped tiles, cracked ridge, failed valley |
| Chimney breast | Damp or staining, worse after rain | Failed flashing, pointing or flaunching |
| Wall next to an extension | Damp where the roofs meet | Failed abutment flashing |
| Top of external walls | Damp, mould or peeling paint | Overflowing or leaking gutters |
| Ceiling under a flat roof | Patches or drips | Splits, failed joints, ponding water |
| Across the loft | Damp insulation, mould on the timbers | Condensation from poor ventilation |
Damp from the roof, or something else?
Not all damp comes from the roof. Rising damp, plumbing leaks and condensation from cooking, washing and drying clothes can all look similar. As a rough guide, damp at the top of a wall or on a ceiling that gets worse after rain usually points to the roof, gutters or chimney. Damp low down on walls, or mould spread around windows and cold corners, usually doesn't.
If we think the cause of your damp isn't coming from above, we'll tell you, so you don't pay for roofing work you don't need.
How we stop damp at the source
Finding the cause
We look at the roof, the chimney, the gutters and, where we can, the loft. We're looking for where water gets in, not just where it shows, and for signs of condensation in the roof space.
Fixing the way in
Depending on what we find, that might mean replacing tiles or slates, re-bedding the ridge, renewing lead flashing around a chimney or extension, repointing the stack, or repairing or re-covering a flat roof. See our roof waterproofing page for the full list.
Getting rainwater away
Gutters that overflow pour water down the face of the wall and soak it. Clearing, repairing or replacing them is often the simplest way to stop damp at the top of a wall. See our gutter repairs page.
Letting the roof space breathe
Ventilated soffits let air into the roof space at the eaves, which helps keep condensation down in the loft. When we replace fascias and soffits, every soffit we fit is ventilated. See our fascias and soffits page.
After the repair
When the source of the damp has been fixed, give the affected area time to dry before painting or replastering. Keeping the room heated and ventilated helps it dry out. If a stain comes back after the repair has had time to work, let us know and we'll look again, because it may mean there's a second way in that wasn't showing before.
Damp prevention for landlords
Damp and mould are among the most common complaints in rented homes. The government's guidance for private renting says landlords are always responsible for repairs to the property's structure and exterior. Roofs, gutters and chimneys are where water usually gets in, so keeping them in good repair is one of the best ways to prevent damp complaints. See our landlord property maintenance page.
Preventing damp before it starts
The cheapest damp to deal with is the damp that never happens. A few simple checks help:
- Clear the gutters once the leaves have fallen, before the winter rain.
- Look at the roof after storms for slipped tiles or lifted lead.
- Check the chimney for crumbling mortar or cracked flaunching.
- Look in the loft now and then for damp insulation or water marks.
- Have the roof checked every few years, or before buying a house. See our roof inspections.
Frequently asked questions
Can a roof problem cause mould inside?
Yes. Water getting in through the roof, or condensation in a poorly ventilated loft, can lead to damp and mould on ceilings and upper walls.
How do I know if my damp is coming from the roof?
If it's near the top of a wall or on a ceiling and gets worse after rain, the roof, gutters or chimney are likely causes. We'll check and tell you.
Will fixing the roof get rid of the damp?
It stops the cause. Once water stops getting in, the damp area needs time to dry out before it's redecorated, and badly soaked plaster or insulation may need replacing. We'll tell you what we see in the loft so you know what to expect.
Can overflowing gutters cause damp?
Yes. Overflowing or leaking gutters can soak the wall below and cause damp inside.
Do you work for landlords?
Yes. We carry out damp prevention roofing work for landlords as well as homeowners.
Are your quotes free?
Yes. Call 07742 720 236 for a free quote.
Damp coming from your roof?
Call Danny on 07742 720 236 or request a free quote. We cover Preston, Leyland, Chorley, Penwortham and the surrounding area.