Today I discovered a damp patch had appeared on an interior painted wall. The patch is about 2ft across and half way between floor and ceiling, in a bungalow.
In the roof space I can't easily get closer than about 15ft from where the wall meets the roof but from what I could make out there is no sign of water coming in there - not conclusive though.
The outside of the wall looks like it might be the culprit. The wall is brick and has (or is supposed to have) cavity wall insulation. The mortar on the outside had some gaps and holes in it about where the damp patch is, which I hastily attempted to fill with some Geocel "The Works" sealant.
If the leaky wall theory is correct then I'm guessing the wall needs repointing? Could it be something else?
Thanks