Chimney & Fireplace

Damp on 1st floor bedroom chimney breast wall

Anonymous user 15/03/2024 - 2.43 PM

I live in a 1958 detached 3 bedroom centrally heated brick house with radiators. The chimney is on the side of the house which is about 10' away from the house adjacent & doesn't get any direct rain on it. The chimney is built on the outside of the original house wall and therefore the walls behind it inside the house are flat (flush). I suffered with problems of damp in the chimney with a leaking stack and so when I got new roof tiles I had the chimney taken off at loft height. The chimney had been a real open fire and I had it swept by a professional chimney sweep. The top of the chimney is open in the loft and sealed from the weather. The bottom of the chimney in my lounge has a decorative only gas fire which has a permanent open vent. I then installed a further 2 airbricks on the outside chinmey wall (one at the top & one at the bottom) which has the original DPC at the bottom. Despite all of this and experimenting covering (capping) and uncovering the top of the chimney stack inside the loft to increase/reduce airflow I am still getting damp readings (over 44% on damp meter) on my plaster in the 1st floor bedroom on the wall immediately behind where the chimney stack goes up on the outside just below ceiling height and about 1' from floor height. When I have inspected inside the chimney (by looking down from inside the loft) I get these same readings on my house chimney wall nearest to me and the mortar, but not on the side walls or outer wall of the chimney. The 1st floor bedroom is well ventilated (windows always open). When I leave the window closed with the room radiator on with the dehumidifier switched on the levels start to fall. Any ideas guys how I solve this issue it's really puzzling me ? Ok so since asking the initial question I have removed the plaster off the wall back to the brick. The bricks behind and the mortar show high levels on the damp meter as mentioned and yet to the left and right of the chimney this is fine ? Would it be worth me having my exterior chimney removed ?