Creating access to chimney in attic

[cjcharles]

Ive got two chimneys as shown below (each with three stacks for ground/first/second floor), in a mid-terraced 1880 house. As Im trying to insulate and improve my house Im part way through planning to put an MVHR in and use the chimney stack (which is out of use) for a fair bit of the pipework.

Is there any reason I cant carefully remove one line of face bricks from the chimney, put in a concrete lintel, and then open up a bigger access to the chimney (probably 4/5 rows of bricks but still surface only, hence not interfereing with the walls between each stack). That will allow me to insulate the chimney void at floor level, and feed an MVHR pipe down to the ground floor. The chimney is between two houses so shouldnt get too damp once insulated, but I can open up the chimney in the rooms more, if it is insulated at roof level.... Once there is access to the chimney stack, I can also feed my MVHR 'external' pipes through the same hole.... (Chimney currently has a basic form of cap on it)

Given the walls between the stack I think I should be ok to remove one row of bricks without any support, before putting the lintel in quickly. Does that seem like a reasonable assumption?

Thanks very much in advance!!

Hence in my mind, would look something like this (with the white being the lintel and the yellow bricks being removed):

 

[Wayners]

I guess you can't remove the outside part of chimney as shared with neighbour?

I've seen holes put through a chimney to run cables ect but they are very thick walls to punch through.
I don't know what the regs are regarding this.

 

[cjcharles]

In principle I could remove the chimney externally down to my planned location but definitely a much bigger job, and whilst it might be the ideal solution for insulation and safety it's probably not worth it...

Based on having removed one of the chimneys below (opened up for a cupboard and put a lintel in) , the face wall was only single skim. I'm just a bit nervous as it's quite close to the roof, so figured it might be less stable when removing the bricks...

 

[ree]

OP,
Chimney breast brickwork is no more difficult to work with than any old brick wall but thats not a potential problem - working on a party wall shared chimney breast might be?
And what you have to say about the chimney breast, the flues and the stack is a bit shaky, and could be dangerous?
Given the various MVHR designs then you might run into trouble locating some of them in an enclosed space such as a chimney breast pocket?
Why not bring in a MVHR specialist & a HETAS to give you a heads up?

 

[cjcharles]

OP,
Chimney breast brickwork is no more difficult to work with than any old brick wall but thats not a potential problem - working on a party wall shared chimney breast might be?
And what you have to say about the chimney breast, the flues and the stack is a bit shaky, and could be dangerous?
Given the various MVHR designs then you might run into trouble locating some of them in an enclosed space such as a chimney breast pocket?
Why not bring in a MVHR specialist & a HETAS to give you a heads up?

I spoke to an mvhr person recently but the challenge was routing the air pipes, this was a solution they thought could work if the chimney was accessible to drop a pipe down inside. The actual mvhr would then sit in the attic as is often the case.

Why do you say the stack is shaky/dangerous? The face nearest me wouldn't form party wall work I think, but would be easy to agree with my neighbour if needed anyway, so it is just a case of how involved it is to add the lintel.

Thank you again

 

[cdbe]

I can see an issue, other than the soot. Might not even need a lintel depending on how the flues are laid out inside and if you only need access to feed some ducting down.

 

[cjcharles]

I can see an issue, other than the soot. Might not even need a lintel depending on how the flues are laid out inside and if you only need access to feed some ducting down.

Thank you, I assume you mean can't see an issue... I think I'll do it for good measure, but perhaps not worry too much during the process then. Thanks again

 

[cdbe]

Yes. Not the best picture but it'll be something like this inside so you could remove a few bricks to find your individual flues and create openings.