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What Might be Causing Underfloor Joist Damp

Posted: Thu Oct 12, 2017 6:05 pm
by Redrumtum
Looking for some ideas on what might be causing damp underfloor joists and some rising damp along the wall above. All joists beneath and the entire wall have become damp but no signs of rotting. This is an inside wall, i.e, adjoining two internal rooms on either side. The damp proof membrane around the joists is about 18 years old and looks in good condition so I can't imagine how they got wet other than condensation. No apparent leaks from pipes and the walls underneath the joists look dry to me. No mould so I assume this is fairly recent.

Photos below.

Cheers

damp wall.JPG

damp joist.JPG

Re: What Might be Causing Underfloor Joist Damp

Posted: Mon Oct 16, 2017 11:15 pm
by diggerjones
If it's on ground floor it would be lack of air flow

Re: What Might be Causing Underfloor Joist Damp

Posted: Tue Oct 17, 2017 6:36 pm
by Redrumtum
Cheers. Have cleared rubbish out from all the air bricks so hopefully that solves it.

Re: What Might be Causing Underfloor Joist Damp

Posted: Wed Oct 18, 2017 9:55 pm
by diggerjones
You need cross draft, in other words air brick in back wall aswell as air brick in front wall.