chimney stack removed below roof

[David J Williams]

Hi
Someone, I believe the previous tenant removed the chimney stack to make way for kitchen units. In the bedroom above the kitchen it appears he has installed an RSJ to hold the outer stack. It looks like he has capped off the chimney at the top and a chimney sweep said this was okay. What concerns me is the black area on the outer wall below the stack. Not sure if this is damp leaching through the stack. I cannot inspect the internal wall as a battened plasterboard wall was installed

 

[blup]

Probably the build up of damp in the flue/outer wall over the years since the chimney was decommissioned, not helped by the tarry chemicals that form in the flue from the effects of smoke and heat when it was in use. May be ventilate the top of the stack.

Blup

 

[tell80]

fwiw, Below the roof its called a chimney breast - above the roof its called a chimney stack.

Your kitchen c/b is gone but you still have a c/b in the bedroom above the kitchen & in the loft?
Best you post pics of the RSJ if thats possible - or, again if possible, describe how the RSJ is supported?
Two pots show on the stack - did the sweep clean two fireplaces and two flues?
If flues are encrusted with soot & chemicals they need flailing & brushing.
All flues also need venting bottom and top - (you have two air vent cowl's in the two pots on the stack).

Your pic shows "soot" penetration from the chimney flues - the soot has penetrated the masonry gable wall & the render, same with the stack. You can follow the line of penetration on the render down to almost ground level.
The render on other parts of the gable is looking sketchy. Probably damp penetration.

Its possible that the flaunching/capping of your stack is allowing water penetration?


In an older cottage the walls might be 9" solid masonry - do you know what they are?
The interior boarding was probably done to disguise the moisture penetration from the outside, and soot penetration from the flue (see below)?
Often, when chimney breasts are removed, the soot encrusted back wall is not wire brushed clean - that remaining soot will leach through any plaster - it will disfigure decorated surfaces.

At least, you need to look behind the boarding, check the stack flaunching, smoke test & flail all flues.
The only way to deal with the render is to replace it.

 

[David J Williams]

Hi Thanks to all for your most informative replies. The CB has been removed all the way up to the top of the bedroom ceiling. Unfortunately I cannot visually inspect the RSJ as the bedroom has recently been decorated. All I can tell is by tapping the wall it is solid across the top of the wall from end to end and then hollow below where the plasterboard battened wall has been installed.

I asked the Chimney sweep if the top was capped off properly on this chimney and he said it was. He obviously couldn't perform any sweeping on the chimney from ground level. I would hope that the chimney is vented at the bottom but would have to check this from the chimney top. I will probably need to get up and check if there is any water penetration on the stack. The walls are 2 feet thick on the property

 

[tell80]

OP, Go into the loft to inspect the RSJ.

Were what remains of the c/b flues in the loft, & the flues in the stack - were they swept from inside the loft?
Presumably you previously had fireplaces in the kitchen & the bedroom above the kitchen?
If the remains of your c/b in the loft is plain to see then any c/b vents should be plain to see?

With walls 2ft thick then how the c/b & flues became the stack is difficult to visualise, unless the c/b was built into the thick wall?
Your remark in post #1 about "damp leaching through the stack" might be well correct - not my notion of soot leaching through the walls? My suggestions ref the render still stand.

OP, photo's of the c/b inside the loft should help