Hi
We live in a 1950's house and 5 years ago we had cavity wall insulation but only to the ground floor as there is no cavity in the upper section of the bricks higher up.
We have had a few issues with the chimney in our bedroom having what look like damp patches which got worse when it rained. We had our chimney swept before Christmas and the sweeper capped the chimney for us and put a camera down our chimney which showed no damage but the chance chimney was wet inside through rain coming in. The chimney in the bedroom is ventilated.
Very recently, the living room chimney breast has developed a damp/wet looking issue. The living room has an open fire and we have a special cap on the chimney so we can still have fires.
A dehumidifier in the room picked up a bucket full of water every day but it still looks the same. I have attached a photo.
Any thoughts or comments would be greatly appreciated.