Blocking up chimney

[monty9120]

Hi all I brought a 1930s house and the chimney opening had been blocked up I drilled some holes in and fitted an air brick a few years ago the house has a tiny cavity but no insulation with how the bricks are built you can’t fit any in

Fast forward a few years and the chimney stack is in a poor state and has recently been taken down to inside the roof itself

Can I block the vents off in the house now mainly in the second bedroom when it has a big opening

The top will be capped off when work is completed

 

[blup]

No, you need to keep the chimney ventilated allowing free flow of air through the flue(s) and out the top, otherwise you risk damp causing problems in the house and loft. There are many "related threads" in the section below.

Blup

 

[noseall]

Once blocked off from outside, the chimney void becomes internal space. I cant see any benefit of having air travel through the flue any longer. All it will likely do is migrate moist air from habitable rooms into the cold loft.
Block them up.

 

[bobasd]

open up any blocked off firepaces sweep the flue an then an use a 9" x 3" hitanmiss adjustable vent.
always ventilate top and bottom of any redundant chimney flues even if the stack has been dropped into the loft.
through vent an sweep, always.
the idea is to prevent chemicals from soot goin liquid an penetratin through the chimney breast and showin up on the decorated surface of the chimney breast as salts an damp stains.

 

[blup]

If you're in any doubt as to what to do, hit and miss vents on the fireplaces, and a removeable cap (e.g. a paving slab) on the chimney would keep your options open. You will need to keep an eye out for possible damp in either case.

Blup