I'm trying to troubleshoot a problem in a our house.
We have a wet patch on on interior wall. A sample of plaster has been removed all the way to the brick. The mortar between the bricks look as if it could be wet, but the plaster we chipped off was sandy and dry.
We've had a damp company inspect it and the reading was low enough for them to not think it was a problem.
Both times the wall has been wet has been after heavy rain. We've made sure we've cleared the gap beneath the double glazing on the windows in case it was clogged and caused condensation. The wet patch is wider at the external wall and thins down, like a cone on its side- so it definitely looks like it's coming from outside. There's a good 40-60cm between the floor and the wet patch, there's also a damp proof course in so we know it's not rising damp. There's also no sign that it's leaking down from the ceiling.
This weekend we found that the external wall has several deep holes drilled into it, which we've plugged with milliput epoxy.
We're meant to be getting the room reskimmed today, so any ideas of what it might be would be hugely appreciated.
Is it an old house? As in, does it have solid or cavity walls? It certainly looks like penetrating damp coming from the window. Could there be a leaking gutter above the window? Or can you see any damage to the wall around the window on the outside that might provide the water a way in?
The three holes drilled in the wall - are they very near the window? If they're not recent it's hard to see how they'd cause a recent problem. I'd be looking for either a leaky gutter or cracks in the wall or window seals very near the damp patch. It clearly isn't rising damp (no such thing), and the water has to be coming from somewhere.