i did think the weather was the problem after it rained thats when i checked the outside cavity - but then it started to happen in all weathers and the walls were single skimed over a pre-plastered wall of only two years thank you for your quick reply
I may be able to help but I got no idea what you are talking about, you got a damp patch, I got that bit! what do you mean by the outside cavity, you normaly only have one cavity and in theory that is on the inside.
Where is the damp patch, on the inside of an exterior wall I imagine?
How far up the wall from ground level is it wet?
what are the walls made from?
How old is the house?