What to do if you find damp at home

Finding a damp patch, a musty smell or paint lifting off a wall is unsettling, but it is a common problem in older homes and it is nearly always fixable. The worst thing you can do is rush into treatment before anyone has worked out what is actually causing it. Here is a calm way to approach it.

1. Write down what you can see

A few notes now save time later. Try to answer:

• Where is it? Low down near the skirting, up a wall, in a corner, on a ceiling?
• How much of the wall is affected, and is it spreading?
• When is it worst? All year round, only in winter, or within a day or two of heavy rain?
• Is the surface actually wet, or is it more of a stain, a smell or black spotting?

Timing is a big clue. Winter-only damp in cold corners is often condensation. Damp that follows heavy rain points to water getting in from outside. Damp low down that never really dries can be moisture rising from the ground.

2. Check the easy things outside

A lot of internal damp starts with something simple on the outside of the house. Have a look for:

• Gutters overflowing or a downpipe that is cracked, blocked or leaking
• Soil, a flower bed, a path or a driveway built up above the damp course line
• Render that is cracked, hollow-sounding or bridging the damp course
• Leaking outside taps, or a boiler condensate pipe running down the wall
• Missing or slipped roof tiles, and cracked mortar around the chimney

If you find and fix one of these early, the inside may dry out on its own over the following weeks.

3. Check inside

• Is the damp near a bathroom, kitchen or a spot where washing dries?
• Does moisture wipe off the surface, or is the plaster itself damp and crumbling?
• Are trickle vents and extractor fans working, and are air bricks clear?
• Has a chimney been blocked up without a vent?

4. What not to do

• Do not hack the plaster off yourself. It is messy, it can make things worse, and it removes the evidence a surveyor needs.
• Do not paint over it with anti-damp paint or waterproof sealer. That hides the problem for a while and traps moisture in the wall.
• Do not agree to a damp-proof course on the spot from anyone who has not properly tested the wall first.

5. Get the cause found

Once you have had a look, the sensible next step is a survey that finds the cause before anyone quotes for treatment. That normally means moisture readings at different heights, a thermal camera to see behind the surface, and a roof or drone inspection for anything high up. Then you get a plain explanation of what is wrong and what, if anything, needs doing.

If you are in Weston-super-Mare, North Somerset or Somerset and want someone to take a proper look, book a survey or read more about our damp and timber surveys.

This guide is general information, not a diagnosis. If you’re dealing with damp or timber problems in North Somerset, book a survey and we’ll tell you what’s actually going on.