Chimney removal

[johnnyhhhh]

@Doggit at the moment there are two steel beams which sit on the chimney breast, one tied into the party wall and one from an internal wall (as there is no wall downstairs to support the one separating the mansard bedrooms, just the chimney breast, see photos attached which might explain it a bit better), as well as 2 concrete joists which can be seen in the picture(s) a little bit. (@vinn mentioned the remaining top brick flue feather, the concrete joist is very close to the floorboard).
All that to me seems like a lot of expensive work which I'd rather put to the side for now, if our plans change in the future we will be able to dedicate some effort to take the rest out if it needs to happen.




At the moment the building control and party wall bits are stressing me out.. not sure how to deal with the cupboard and how would I go about getting building control involved without any plans for the chimney removal job, we do have full plans for the repair of the external walls (only reason why we are paying this specific structural engineer)..

 

[Doggit]

See, I knew why there would be a good reason not to do it. You'd need to get a welder in to extend the steel beams, but not impossible by any means. Talk to the SE about it. You could pick up a few feet of steel RSJ from a scrap yard,

Building control are normally quite flexible, and they won't come down on you if you explain things to them; as long as the job is done up to standard, they won't worry that it's already been started, but you could talk to the builders as to how they'll stabilise the chimney breast in the loft, and as much as I shouldn't say this, then if the works up to a good standard, just get on with it.

There's no party wall issue at all as long as there's no structural work involved, and as long as the party wall is two bricks wide, then it'll be stable enough to handle the cupboard being removed. The builders will check to make sure that the cupboard isn't supporting anything, and it shouldn't require too much remedial work if by some odd chance that it is.

I certainly wouldn't say that there's anything here to get stressed over, to chill out, and take it in stages. Best of luck

 

[vinn]

When the OP bought the property no issue was mentioned ref a cert of completion?
Given the dubious arrangement of the missing wall & the concrete lintels bearing on (what?) and the stack & partial c/breast removal - nothing was said by the surveyor or so it seems.

Where have the sudden mentions of selling come from? The OP appears to have just moved in?

If any issues occur that could be considered structural/H&S then BCO would immediately become involved. I know of an instance where BCO was called, she called in the Council Engineer, and the party walls lacking (removed) buttressing c/breasts were propped at client's/builders expense.
Bco's take immediate action where party fire walls are missing or holed in lofts.

A party wall issue/collapse in London a few years ago involving 3 or 4 terraced properties had had BCO's on site days before the crash.

 

[vinn]

You knew not to do what? Remove the cupboard? The bedroom c/breast?

OP, you've been dribbling out information since your first post - now this business about steel and concrete lintels & a double knock-through below. Plus the late arrival of significant photos.

The best advice by far on this thread was given early on by cjard - best stop all work and call in the BCO, and then proceed according to BCO's instructions.

Best of luck for the rest of the job. I do hope that you are not intending to flip this property?

 

[johnnyhhhh]

A surveyor hasn't seen the property as we bought it at auction, even though it's our first property this is what we could afford.
We did discuss with quite a few to bring them in but a few advised there's no point at this time as we already bought the property... so we paid for asbestos surveys and structural engineers instead.

@vinn
I haven't mentioned selling as we are not going to, we are trying to gain some space upstairs in the bedrooms and properly insulate the house as at the moment it's just concrete and we're spending excessive amounts on heating.

Also, I didn't realise other photos made a difference to my original post however they did help clarifying why we are not taking out the chimney breast downstairs.

 

[cjard]

Taking the chimney breast out isn't really structural work in the trues sense of the word

So you'd assert that a chimney breast never forms a buttress to a wall?

and a steel plate under what's left of the old chimney in the loft.

This is something I've never understood about chimney removal - why remove all supporting masonry from below a ton of eccentric load (including a defunct external chimney) and then leave that load poised over an inhabited house on a couple of steel brackets/fixings that can rust away in the "former salts of combustion and damp" environment, when it'd only be a few quid more to take the entire thing out and slate over the hole in the roof for a better, more leakproof, less draughty solution..

 

[Doggit]

So you'd assert that a chimney breast never forms a buttress to a wall

No, but you've made an interesting observation. Houses have walls that stand up on their own, so a chimney that can act as a supposed buttress isn't a necessity, just an addition. A wall without a chimney, is just as strong as one with one.

As to the gallows brackets; some people on this site seem to think that they support the remaining chimney breast, but they don't. The chimney is tied into the wall by every other brick, so the steel plate resting on the gallows brackets is only there to stop the bricks coming lose, and dropping into the room below. You'll get a degree of surface rust on it, but it's only in extreme locations that you'd get serious rusting, and then the BCO would specify rust protection.

As to the common sense approach of taking the whole chimney out and tiling over the hole, sometimes it's a very valid viewpoint, but most chimneys have a corresponding chimney in the house next door, so you can't always take out just your own one. In this scenario, as the chimney is on an internal wall, the OP could well do a complete removal, but having seen how this thread has gone, I'm sure there's a valid reason against it.

 

[cjard]

No, but you've made an interesting observation. Houses have walls that stand up on their own, so a chimney that can act as a supposed buttress isn't a necessity, just an addition. A wall without a chimney, is just as strong as one with one.

I'm not certain I'd agree - dig deep into Part A and you find all sorts of wonderful (eyewateringly boring) tables/calc relating to wall heights, thicknesses, lengths and buttressing requirements etc, suffice to say that there's a very real possibility that a chimney breast or two on either side of a slim wall in some houses stands a very good chance of being a vital buttressing support to the wall..

As to the gallows brackets; some people on this site seem to think that they support the remaining chimney breast, but they don't. The chimney is tied into the wall by every other brick, so the steel plate resting on the gallows brackets is only there to stop the bricks coming lose, and dropping into the room below. You'll get a degree of surface rust on it, but it's only in extreme locations that you'd get serious rusting, and then the BCO would specify rust protection.

Sure, I can go for that, in the sense that a lintel only truly supports the triangle of bricks over an opening, but surely then if the entire remaining stack were intrinsically stable simply by removing the lowest loose bricks (the ones that rest on the brackets and have no support from any other brick beneath it) you'd have a nice triangle of bricks stepping out, away from the party wall and upwards as they turn the corners and head towards a meeting point -> to this end can you argue that gallows brackets are unnecessary as the same effect can be achieved just by removing bricks? Why doesn't everyone just do that?
I've a suspicion that combined with the deleterious effects of combustion salts on the mortar holding the bricks over the years, that gallows brackets are supporting/intended to prevent the collapse of more than just a few of the lowermost bricks, no?

As to the common sense approach of taking the whole chimney out and tiling over the hole, sometimes it's a very valid viewpoint, but most chimneys have a corresponding chimney in the house next door, so you can't always take out just your own one.

Which was another thing that I never truly understood, I think - is it just aversion to disrupting the paired chimney? I foresee that two chimneys in e.g. a figure 8 configuration could be reduced to just one in an o, by removing the other part of the chimney and tiling over the hole.. true that you've got to flash effectively the same lot of flashing if there's still a chimney there on the neighbouring side, and you might have an ugly internal wall that became external - perhaps this is why they're left; much hassle for minimal risk, rather than technical difficulty

 

[Doggit]

to this end can you argue that gallows brackets are unnecessary as the same effect can be achieved just by removing bricks? Why doesn't everyone just do that

Essentially you're right, but you'd need to corbel the whole chimney breast to stop the bricks in the middle from dropping. Your method only deals with the sides. And as to the chimney breast forming a buttress on a weak internal wall, you've made a good point there if it was single wall. It's a shame more people don't think outside the box like you seem to.

 

[cjard]

When you say bricks in the middle, do you mean the bricks making up the chimney that are furthest from the part wall? Would they not be supported by the sides (albeit one or 2 might fall out)?

I made this sketch to highlight what I mean:

 

[stuart45]

I've worked on quite a few new builds in the past where the chimney breast only had the odd tie into the party wall, although in theory it should have been every other course. Mortar smeared up the jambs would be used to cover up.

 

[cjard]

I'm amazed that new builds still have chimneys! Perhaps some token gesture to stop the flue from the gas fire cooking something it shouldnt

 

[Doggit]

(albeit one or 2 might fall out)?

That's what the plate sitting on the gallows brackets designed to stop. Your corbeling trick works for the side, but not really for the front, unless it's a pretty narrow chimney of course. Once bricks start falling out, anything can happen - and often does.

I've just taken out a chimney breast in the kitchen of a 1930s house, and although it was tied in every other course, the throat just came down in one go. I can only assume they built a frame and that supported the throat as they mortared it in to the surrounding chimney breast as they went up.