The short answer
condensation is moisture from inside the home settling on cold surfaces. Damp is water getting in from outside or from a leak. Mould is what grows when either is left alone. Work out where the water is coming from, and you'll know what to do.
The quick comparison.
| Condensation | Penetrating damp | Rising damp | Leak | |
|---|---|---|---|---|
| Where | Windows, cold corners, behind furniture, bathrooms | Patches on walls or ceilings, often upstairs or on outside walls | Bottom metre of ground-floor walls | Near pipes, under baths, below bathrooms |
| When | Worse in cold weather and mornings | Worse after rain | All year | Constant or after using water |
| Looks like | Water droplets, black spotty mould | Brown or yellow stains, blistered paint | Tide mark, flaking plaster, white salts | Localised wet patch, may drip |
Condensation.
By far the most common. Cooking, showers, drying clothes and breathing all put moisture into the air. When that warm, wet air meets a cold window or wall, it turns back into water.
What helps:
- Use extractor fans when cooking and showering, and leave them running for 15 minutes after.
- Put lids on pans.
- Dry washing outside when you can, or in a room with the window open and the door shut.
- Keep trickle vents open.
- Keep the heating on low and steady, not off then blasting.
- Leave a small gap between furniture and outside walls.
- Wipe windows down in the morning.
Penetrating damp.
Rain getting through the building. In older North West terraces and semis, the usual suspects are:
- Blocked or leaking gutters and downpipes.
- Slipped or missing slates and tiles.
- Worn pointing between the bricks.
- Failed seals around windows and doors.
- Cracked render.
What helps: find and fix where the water gets in. Start with the gutters, because that's the simplest thing to rule out. The wall will dry out once the source is sorted.
Rising damp.
Less common than people think. It's ground moisture moving up through a wall, and it rarely gets higher than about a metre. It's often confused with condensation at the bottom of a cold wall, or with soil or paving that's been built up above the damp-proof course outside.
What helps: check ground levels outside before anything else. If you think it's rising damp, get an independent opinion before agreeing to treatment.
Leaks.
A damp patch that doesn't change with the weather often comes from plumbing: a weeping pipe joint, a failed seal round a bath, or a leaking radiator valve.
What helps: have the leak found and repaired. Small leaks rarely stay small.
What about mould?
Mould is the result, not the cause. You can clean it off with a mould remover, wearing gloves and with the window open. Don't brush it dry. But it'll come back unless you deal with the moisture that's feeding it.
If mould is widespread, or anyone at home has asthma or breathing problems, get help rather than cleaning it yourself.
For landlords.
Damp and mould in rented homes is taken seriously. If a tenant reports it, look for the cause before assuming it's how they're living. Not sure where your property stands? Take the free Property Health Score. Seven questions, about two minutes.
When to call FixAble.
Plumbing leaks and failed sealant are the kind of repairs a FixAble plan is for. Comfort and Complete plans also include a gutter clearance and roofing repairs. Labour is included, with up to £250 of materials on every job.
Structural work isn't included. See what's not included.
FixAble works across Greater Manchester and surrounding areas, within 30 miles of Ancoats.
