Hi, looking for some advice. I have a damp patch about 600mm square on an upstairs exterior wall. It's been fine up until now but with heavy rain we've had beating on the back of the house it seems to have made its way through a crack I think around our window. I've sealed the crack with silicone but the damp patch doesn't really seem to drying out and it's also grown a small layer of fur. Think the plaster has blown also as sounds hollow when you tap it. Is it best to knock out the plaster and start again or do you think I could paint some damp sealant over it and repaint?
My only worry is the damp will come back? Any advice?
Thanks
My only worry is the damp will come back? Any advice?
Thanks