Removing chimney breasts in a cavity wall house.

22 Jan 2017
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United Kingdom
Hi all,
I have just finished removing a dorment chimney breast upstairs and I'm halfway done on the lower floor. (Loft chimney breast and chimney was already removed 30yrs ago when we had a new roof) anyway this chimney breast was removed to increase space in the upstairs bedroom and the dining/kitchen. Also this is not the main chimney which is on the party wall, (semi detached house) but the chimney breast that was on the opposite side of the house. Anyway as I have a cavity house when the chimney breasts were removed the cavity is obviously closed of but the back of the original chimney is double bricked back to back tight leaving no gap and I was wondering how should I deal with this without disturbing the outer wall. I was told by a friend that I should batten out level with the inner wall and not disturb the inner bricked wall but I am a bit unsure about any potential damp the bricks may have as they have no cavity.

Any thoughts?

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So you have an external wall cavity that you filled with solid brickwork in the old chimney flue position?

If there's no signs of penetrating damp then you could leave it as it is.
Or remove the solid brickwork and simply brick up the inner skin.
Do you have injected CWI?
Did you remove all soot traces from the brickwork?
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Hi vinn,

No cwi also you helped me the other day in another thread regarding that and bettening lol. I have not bricked up the cavity but the back brickwork where the chimney breast was doesn't hold a cavity but the inner wall is bricked back to back to the outer wall. This is about 1200mm wide and full height of the room. I am a bit reluctant to remove or disturb the inner wall as is butted tight to the outer brickwork I am worried I may disturb to outer wall. There is small trickles of water penetrating the brickwork as it's raining right now. Also I have been removing soot traces as I've gone alone taking it down.
I hope that my previous suggestions helped you.

Quite what you have I dont understand - can you post pics of inside and outside?
The penetrating water is concerning. Looking back I see that you have render - pics are really a must.

Just thinking - are you referring to the back wall of the chimney breast or, same thing, the back wall of the flue?
That wall is still the inner skin in a cavity wall chimney breast.
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If the inner wall is not keyed into the outer wall, then the you could use a stone saw with water dust suppression to cut along the mortar lines, at which point the bricks of the inner wall will just lift off with a little plying with a chisel. The idea is that by cutting with the stone saw you are not placing the stress on the wall that a hammer and chisel would. You could then build up the inner wall to make a cavity, bearing in mind you would need to fit brick ties.

An Arbotech Wall Saw would be an alternative to a stone saw.
Thanks for all your suggestions guys. The tiny area where the water was coming in has now gone I noticed outside on the render that there was a crack running about a metre in length horizontally. My friends a builder and he advised me to seal the crack temporarily as I do intend to have the house re rendered in the future. Anyway the inner wall is indeed toothed to the outer and that's why I am reluctant to remove it. I have been told to shutter the gap difference using concrete/sbr mix just to level things off. Also I have not seen any water penetration since that first day and we have had very bad weather as of late.

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