Looking for some advice... we recently moved into a 1930's property and have renovated the bedroom. We removed all the old window trims on the bay window and replastered the whole room. Now we have had very heavy rain and a wet patch has appeared in the corners underneath the window sill. When we removed the wallpaper there didn't seem to be any evidence that this had happened before. The plaster had blown around the bay but there was no evidence of it ever being damp (it wasn't black or anything) so we think it must be to do with having removed the window trims. Any ideas? Window trims are going back on. We only removed them to replace them but thought best to decorate first. Pics attached of the patch and also the bay once plaster had been removed. Thank you!
We also removed the ceiling above the bay, it goes into a pitched roof and did have lave plaster, we removed it (just the ceiling to roof void was visible), battened it, plasterboarded and replastered. Don't think this could be anything to do it with it but just incase.