Argh - partially removed chimney breast!

[a twig]

So far with our property, everytime we have removed a built in wardrobe, we have uncovered something bad behind it, be it a leak from the roof (which was the final straw which ultimately prompted our new roof), or some interesting modifications to joists/wiring etc.

This is definitely the best one yet, ripping out a built in wardrobe in an upstairs bedroom, I uncovered a chimney breast...

This matches the remains of one long capped off on the roof - initial inspection in the loft had been hampered by the cold water tanks, but from what I could see it appeared that the capped off chimney had been supported with some large timbers in the roofspace to allow the removal of the breast itself beneath. While this wasn't ideal, there isn't much stone above it so I wasn't too worried. It now appears that this wasn't the case...

Feeling somewhat nervous I nipped downstairs to the dining room beneath to find a completely flat plasterboard & studwork wall. Some initial exploratory holes at the base of the studwork revealed some debris from jackdaw nests... so the lower chimney breast had been removed...

I then carefully drilled and cut away a small amount of plasterboard from the ceiling of the dining room - now stood effectively underneath the first floor chimney breast. From what I can see through the small hole there appears to be just some yellow painted 4 x 1 timber above the plasterboard :shock: i.e. supporting the weight of the remaining upstairs breast! I haven't yet been able to determine what is holding up this timber but based on previous I'm not holding out a lot of hope that it has been done correctly, and it wouldn't surprise me if this is just bridging the existing joists.

Even if a gantry bracket has been installed I don't hold out much hope for its strength given the age of the lime mortar in the stone walls.

So It looks like a change to the planned schedule, the other half's utility room will have to wait!

As I see it I have three options:

1) Re-instate the lower breast in block work, with appropriate ventilation at the bottom, then when we re-plaster the dining room, hopefully the modern materials won't be too noticeable.

2) Remove the upstairs breast as well and properly support the remaining stack (only protrudes a foot above the roofline so wouldn't be too bad).

3) Steels...

I'm currently leaning towards option 1 - any comments or better suggestions?

Happy bloody Christmas to me... :evil:

 

[Flyfisher]

Not sure if this is a matter for commiserations or congratulations. Commiserations, certainly, about such a dangerous-sounding bodge being perpetrated in the first place, or congratulations (of a sort) that you've discovered it before something calamitous (not to mention injurious) has happened.

As for the proposed options, I suppose it depends on the impact on the lower room, so you're the best positioned to judge, but my inclination would be towards reinstatement and perhaps even a functional fireplace. I'd only consider the steel option if they would be completely invisible. If you are replastering the lower room then I don't see why the block construction would be noticeable in any way at all.

Not pleasant to discover such unexpected thing. I hope there are not too many more built-in wardrobes to investigate!

 

[TheForge]

We have a very similar issue with a stack that has been left above the roofline on one gable of our forge, supported on a single piece of 6x2 timber fixed to the rafters following removal of the breast/hearth below. I'm afraid I can offer few answers, just additional problems!

Bear in mind that a large proportion of the chimney stacks load is bearing directly down through the gable wall and it may be in a dynamic equilibrium as a flying feature! It's the danger of the shearing force pulling it over that needs addressing

We have the same dilemma, although to make matters worse the gable end is leaning in at the top with the weight of the chimney and the roof both spreading and racking. To combat the spreading we intend to add some yacht rigging at the foot of the principal rather to act as a collar and prevent further lateral expansion. All is subject to LBC.

The intention is to rebuild the breast in order to support the chimney and act as a buttress for the movement in the gable. However there are a few issues:

I. How do we 'connect' the new breast to the remaining stack, do we need to needle the stack?
ii. How do we gauge the design of the stack? The forge hearth opposite was rebuilt c1900 and offered little to go on.
iii. Do we build in block and face in appropriate brick or be entirely authentic and construct entirely of brick?
iv. Where do we source appropriate bricks? The existing are clearly hand made and include a variety of sizes along with many broken bricks.

Our friendly structural engineer has recommended tying the new stack into the gable every 5 courses.

The final question has been hopefully and rather excitingly answered by Tony Mugridge, who visited recently and is keen to help us hand make replacement bricks on site to the existing sizes using local clay - the only issue is that we'll need a couple of thousand!. The forge was once part of an estate 'works' (we also have a sawmill and carriage works/carpentry shop on site) and to the rear an old brickworks is marked on early OS maps. After some amateur archaeology we think we've identified the clay pits on the inside of a diverted brook, so have probably the same source of clay as the original brick makers. Tony dated the existed gable bricks to probably the early 1700s, although there irregularity suggests either waste bricks were being used or that possibly some older second hand bricks were encompassed in it's construction.

Any thoughts would be welcomed!

 

[a twig]

We have a very similar issue with a stack that has been left above the roofline on one gable of our forge, supported on a single piece of 6x2 timber fixed to the rafters following removal of the breast/hearth below...

Hey get your own thread! :wink:

Yours sounds a lot more fun than ours! Cheers for the advice so far gang, plenty to ponder on! Any more tips / advice very welcome!

 

[Zebra]

I think I'd make a bigger hole in the dining room ceiling and have a proper look. Preferably the day before a New Year's Eve dinner party, as the falling dust and debris would provide an interesting topic of conversation. How old is your house again, a twig?

 

[a twig]

Hi Zebra - yup further exploration will be order of the day tomorrow - have a large mahogany dresser to move first though!

House is approx 1850s - haven't been able to find an exact date yet though.

Better half doesn't really want the chimney breast re-instated, but I think if I can convince her that we can make it into a feature wine rack or something she might come round!

 

[plasticpigeon]

No brainer for me, I would reinstate it. Why do people do these things? Lots of work to make things worse, I just don't understand.

 

[Feltwell]

It always scares me that things like this get sold as being the "right" way to support the remains of a redundant chimney breast / stack:-

http://www.screwfix.com/p/sabrefix-...arch-_-SearchRec-_-Area1&_requestid=49474#_=p

All that masonry supported on a couple of brackets bolted into brickwork or (even worse perhaps) stonework? No thanks. Mind you, even this would be a distinct improvement on what's described above!

Twig, I'd vote for "re-instate in blockwork", and add a suitable fireplace or perhaps stove if appropriate. Whatever you do should involve Building Control, as of course the original removal should have done!

Edit - I've just noticed that on the Screwfix website, underneath the gallows bracket shown above, they have "more items to consider" - including a Helifix crack repair kit. Take that old chimney breast that's in the way out, support several tons of masonry on a couple of brackets and 4 bolts, oh yes and have you considered buying a crack repair kit for the repair to your gable end wall that you'll now need to do later?

 

[plasticpigeon]

I have always though that supporting a stack on a bracket was a terrible idea as it adds a turning moment onto the wall where freviously there was only a downwards force. I'd consider most old lime mortar so weak that it only fills the gaps and adds a bit of friction. My neighbours supported their stacks on brackets, but thankfully they share the chimneys with the neighbours on their other side.

 

[Feltwell]

Agreed, the turning moment would be my concern, that and the fact that a chimney stack acts as a buttress which is important in some locations.

Any alteration is supposed to involve Building Control and, if a party wall, the relevant permissions for that as well - as for how often that happens in reality, I suspect not that often....

Apparently BC's attitude to chimney breast removal varies by authority, some are quite stringent, won't allow brackets and insist on a structural engineer's sign off, but others are shall we say more relaxed in their approach.

Even disregarding the conservation concerns for a moment - to remove a chimney breast is a horrible, dirty, messy job that would cause considerable disruption and a lot of making good afterwards for very little return in terms of extra floorspace - why do people bother?

 

[a twig]

Thanks for the advice gang, reckon we will go for re-instatement.

Won't make it a live fireplace as we already have several, but the missus is keen on have a "feature" fireplace, putting something suitably pretentious in like a wine rack/bit of art (although she balked at my suggestion of a nicely polished V8 engine block )

I know it isn't very "period" and I'm sure such a feature fireplace suggestion will cause a few raised eyebrows amongst the senior members of this parish, but I suspect this will probably be our way forward. Thanks for the advice gang, I'll carry on with the explorations and keep you posted on progress!

 

[Feltwell]

(although she balked at my suggestion of a nicely polished V8 engine block !

No appreciation some people - a Rover 3500 would be great, although it would look even even better bolted into a nice P5B Coupe or a Stage 1 Land Rover rather than a dining room!

 

[a twig]

Ha, if I have a Rover 3500 knocking around it would certainly be sat in the engine bay of my '72 Series III! As you say though, some people, no appreciation...

 

[a twig]

Right, explorations complete, side walls are supported by a bit of angle iron on one side, and some 4" x 2" on the other, with the front wall resting on a joist...

:shock:

The amount of damp around the bottom, plus mud and twigs from jackdaws, also indicates that the "capped off" chimney isn't very well capped...

Borrowed some acro props from a friend which will be going in tomorrow morning. Then I need to book a few days off work!

Stage one: Cut up and break out concrete slab in front of the removed breast

Stage two: Put in proper footings

Stage three: Build up block work walls, tying into stone wall as I go.

Stage four: Fill gap between block and existing structure to join the two together.

Stage five: Remove acros and put in lintel so it supports existing joist

Ideally I would like to cut the joist out and build the block work up to it so it is all one solid wall, but I can't figure out how to support it while doing so! So joist will be "doubled" up, with the weight being taken by the lintel/side walls.

Can anyone see any flaws in my plan or suggest better ways or proceeding?

 

[plasticpigeon]

Could you use strongboy prop ends to support above the lintel? It is amazing how much masonry there is in a chimney breast as the flues are quite small so particularly at ground floor height where there is only one flue and the chimney breast is at its widest, it is almost solid masonry. The chimney breasts must be the strongest bits of my house.

 

[88v8]

When a breast is removed, only a small part of the weight is carried by whatever is put in to support it. Most of the weight transfers diagonally through the brick bond into the wall.
The unsupported part is a just triangle of bricks on each side, and an equilateral triangle across the front. Scarcely enough bricks to fill a wheelbarrow. However, as has been said, it does create a modest turning moment in the wall, which is OK provided the wall is up to it.

If you don't really want a solid breast downstairs, you could just put in a couple of iron or wood pillars to support the corners, with an angle-iron frame for the breast to sit on. That will be more than adequate.

Thinks.... how many badly removed breasts must there be... when we did last hear of one collapsing, I mean actually collapsing... errrm... never?

Ivor