We purchased a steel frame bungalow 18months ago. All going well, but noticed after we stripped the years of wood chip paper off and redecorated we started getting damp on the external wall at the front of the house. Last winter (our first) I thought it was damp, the result of the house being locked up for a time, perhaps even the wallpaper not allowing the walls to 'breathe' Spring summer came, windows were opened at any chance etc and so no problems all gone – until now! Its back with a vengence!

The bungalow was constructed in 1965 and appears to have a decent dpc – could it be condensation? Its there first thing in the morning predominately in the corners and then disappears through the day! The rooms with the problem are bedrooms? If it is how can we check? Short of opening all the windows (old type double glazing unvented) and letting the heat out what can we do?

cheers

Could be condensation, if youve got the old 'crital' style metal windows there is probably no trickle vents (little slidey vents at the window head), all new builds require background ventilation to help overcome condensation problems.

If its a steel frame it could also be cold/thermal bridging i.e. where outside cold air/cold frame meets warm inside air = condensation. From your description of the condensation being in the bedrooms and mainly in the mornings points to insterstitial condensation (warm air from body temp/breathing/heating meets cold air/surfaces). Almost certainly not damp if its visible all the way up the ext. walls.

Best get a qualified surveyor to take a look.

Thanks Glenn

It's the internal not external walls – (but I guess you mean that?)

A qualified surveyor it is then – cheers

Yeh, meant the inside face of the external front wall.

Have a look here, inparticular the positive input and multi point ventilation systems, theres a lot of good info on this site. Give them a call they used to have a home vent division that done surveys.

Thanks GR – that's what I've been thinking

Will get a survey done anyway to discount any other 'issues'

cheers
TS

Would a agree with Glenn , sounds like Interstitial condensation if possible try leaving the bedroom window open / by a de-humidifier to see if this solves the problem, it is not uncommon for this to happen during the winter months so dont get to worried. Try to increase the air circulation / temperature as well ie dont leave bedroom doors shut. (I have just qualified as a building surveyor)

Is it definitely steel frame and not timber?

Also, what is the wall construction? (brick/block cavity, external cladding, internal dry-linig, etc?)

I'm not clear whether the damp is appearing on the internal walls (partitins) or the internal face of external walls?

Be aware that if there is damp/condensation visible, this may be affecting concealed steels (corrosion) or timbers (rot).

Regardless of the above, I'd agree it sounds like a condensation issue resulting from a combination of high moisture levels/heating internally, cold external temperatures and poor insulation between the two. Interstitial condensation normally refers to water vapour condensing out of the air within the building structure (as it cools)- hence my concern over hidden corrosion/rot.

Def condensation.

You can board out the wall with insulation backed plasterboard. That will sort it. Vents will help but they're dealing with the symptom not the cause. They may well not work when the weather is particularly cold (or rather a big differential between inside and outside temps), when the air is humid (as it tends to be in winter, >95%), or when there is little wind to drive the vents.

If you turn up the heating to try and cure it, you'll find it only makes it worse.

C