What Might be Causing Underfloor Joist Damp Damp can be a major issue in the home. Find answers to questions or post your own here.

[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

[diggerjones]

If it's on ground floor it would be lack of air flow

[Redrumtum]

Cheers. Have cleared rubbish out from all the air bricks so hopefully that solves it.

[diggerjones]

You need cross draft, in other words air brick in back wall aswell as air brick in front wall.