Redundant flue

[erikwoolf]

There is a redundant flue in one of the rooms. Chimney stack has been removed a couple of years ago so top of the flue is completely sealed off. I am planning to insulate that wall and the flue is running a few meters vertically. Would like to avoid having a gap in the wall that may compromise the insulation effect but I also wasn't 100% sure what to do about it. Currently it has been cleaned from residual debris so I can fill it with something else such as some form of flexible insulation perhaps?

 

[a twig]

I would fill it the actual hole in the wall with bricks and lime mortar to be honest

 

[a twig]

In terms of the void, I would ventilate it internally with discrete brass vents top and bottom rather than fill it. Operating on the principle that moisture will probably get in somehow so allowing it out again is usually better