Hi, My partner and I are new house owners and slowly learning so many new skills! Was wondering if anyone could help with a patch of blown plaster, see photo. We recently noticed this patch at the back corner of the house. There’s a roof right above this and the gutter is on the exterior corner of where the damp patch is so we think there’s a leak of some kind which is why it’s been caused. Roof guy is coming tomorrow to look at the cause but wondering on any tips to solve the blown plaster? Do we need to test the rest of the wall and how do we do this? How do we know it hasn’t spread? Do we need to get someone in to fix it or could we do it ourselves? And any tips to make sure it doesn’t come back! Any help would be greatly appreciated.
It doesn't look like the plaster has blown - just that the damp has lifted the paint. Does the plaster sound hollow when you tap it or feel loose at all? If not it should be alright. Get the gutter fixed or find and cure the source of water ingress, let it all dry out and then redecorate. You might need some cover stain or something first - Astramax or Wayners will give good advice.
Thanks for your response! Unfortunately it does sound hollow and there’s some movement when pushed. Is there anything you’d suggest to do?
Oh. Sorry about that. You've little choice but to remove the loose plaster and then assess the scale of repair required. If not too bad, you may be able to make good with some easi fill or similar. The most important thing though is to deal with the source of the damp first.
It may well be a leak from a blocked gutter, however it also may be condensation, or both - an external leak will make the external wall wet which will make it colder through evaporation. Bottom of the wall on an external corner is going to be the coldest spot on the wall. If the wall temp drops below the dew point of the room air you get surface condensation. Either way the plaster has to come off and be repaired. Doesn't all have to come off. Strip the patch and leave it a while to dry out. How old is the house? Good ventilation is your friend in helping to avoid condensation. Don't rush off and get a survey from a "damp" company. Most are snake oil salespeople who will inevitably find "damp" and sell you all sorts of witch doctory remedies. Most of which are totally useless
Thanks for your help! Roof specialist came round and fixed the problem - now just need to wait for the wall to dry out and sort that!