Damp Proofing

Damp patch on the bedroom wall where it meets the ceiling

Anonymous user 07/03/2024 - 2.30 PM

Hi, We keep getting a damp patch on our bedroom wall, where the wall meets the ceiling. The wall is external and is the only one in the house having this issue. There are no signs of moisture on the ceiling, we have loft insulation on the entire surface of the house. The house was built in the 80s, I am not sure if the walls have cavity insulation. We tried applying stain block, but the patch re-appeared. As long as we sleep with the window open a bit (1 cm gap on the most open edge) the patch doesn't re-appear. We slept with the window closed for one night (due to strong winds) after a month with no issues and the patch was back in the morning. Is there anything we could do to prevent this from happening other than keeping the window open over night? I don't mind keeping it open, but sometimes we have to close it due to bad weather or loud noises...