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Hi all, I am wondering if there is an easy solution to my insulation problem. We have cold spots in our spare bedroom, we have an old chimney breast stack running through the bedroom wall which when viewed from the loft is just a big cavity with no filling or insulation, we are having a case of the part of the wall where the old breast is is getting wet and almost sweating, we have used mold sealant paint and that hasn’t helped the issue, I am just wondering if I get insulation like rockwool and use that to fill the cavity if that will solve our issue or if there’s anything else to suggest.
Thanks in advance

Hi lachic21,
You have a damp problem which you probably will not be able to cure completely. From you description it sounds like your chimney has been removed down into the loft. If the top has been left open and your loft is not cross ventilated it may be condensation. If you loft is cross ventilated then the damp could either be rain penetration if it’s an outside wall or condensation from room the chimney passes through.
You could try sealing the top and see if this has any effect, the problem is it may take months before you see if it has worked.
Regards S