Ventilation & condensation
control in Kent.
Condensation isn't a damp problem in the wall — it's moisture in the air landing on a cold surface. Anyone selling you a damp course for it is having you on.
Warm wet air, cold surface, black mould.
A household generates a surprising amount of moisture — cooking, showering, drying washing indoors, even breathing. That warm moist air moves through the house until it meets a surface cold enough to make it condense, and then it deposits its water there.
Which is why mould appears in the same places every time: corners of external walls, behind wardrobes pushed against them, along window reveals and on cold cills. Those are the coldest spots in the room, and they're where the air gives up its moisture first.
Modern draught-proofing has made it worse. Older houses leaked air constantly, which was wasteful but moved moisture out. Seal a house up without adding ventilation and the moisture has nowhere to go.
Signs it's condensation
- Black spotted mould in corners and around windows
- Water running down the inside of the glass in the morning
- Mould behind furniture against an external wall
- Much worse in winter, better in summer
- A musty smell in bedrooms and bathrooms
- Damp on the surface rather than within the wall
None of this needs a damp proof course. It needs the moist air getting out of the building.
Small kit, large difference
Humidity-sensing extract fans, clear or new air bricks, and where the whole house needs it, a positive input unit in the loft that gently pushes fresh filtered air through the property.
The least glamorous thing we fit, and often the most effective.
Nobody rings us excited about an extract fan. But where condensation is the problem, ventilation solves it for a fraction of what a mis-sold damp course costs.
And we'd rather fit a fan you need than a damp course you don't.
- 01
Survey the whole house
Where the mould is, where the moisture is generated, what ventilation already exists and whether it works.
- 02
Rule out the alternatives
Meter readings to confirm it's surface condensation rather than water in the fabric of the wall.
- 03
Recommend the right level
Sometimes it's an extract fan and unblocking an air brick. Sometimes it's a whole-house positive input unit.
- 04
Fit and test
Installed, wired, tested and left working, with the mould treated at the same time where needed.
- 05
Practical advice
What to change day to day — drying washing, lids on pans, keeping trickle vents open. Free, and it helps.
Black mould in the corners?
Send us a photo. If it's condensation we'll tell you, and the fix is usually far cheaper than you're fearing.