damp bedroom wall

[joquin]

hi, what is causing this damp wall ?
cottage with 50cm thick stone wall. this is upstairs bedroom. the roof is pitched
without a roof space. the damp as you can see is the while wall but generally start from the top and spreads downwards.

 

[joquin]

 

[mrrusty]

The pattern looks like liquid water running down not surface condensation on a cold wall. Could be leaking roof or just possibly a huge amount of loft condensation. If it had a non-breathable cold membrane, and an open air path to the nice warm humid air from the house below conceivably there could be enough condensation to cause that, but I think I'd be looking at leaks first. What possibly points away from a leak is the fact that it isn't a very localised damp patch.

Get up in that loft and have a look. It just conceivably could also be a leaking water pipe.

 

[joquin]

hi thanks, we don't have a roof space on that part of the house. no pipes either up there. it does dry up considerably in the summer even when we get rain. it got a lot worse since the temp has dropped over the last week ? so could be condensation then ?

 

[mrrusty]

If you don't have a roof space you can get in to, and there is nothing obvious from the ground, I would cut a neat hole in the ceiling to get a good look at what is happening in the roof void. It's impossible to guess.

 

[joquin]

OK thanks