Removing chimney breast

[J Pearse]

The 1930's semi we are moving into has a chimney breast in the dining room we are looking into removing. I know these jobs will need regs approval. Looking in the attic the appropriate breast/flue is the right side in the picture and looks very insubstantial (compared to the one on the left- lounge side) I'm assuming a pair of gallows brackets *should* be more than sufficient pending approval.  I know in many cases they now recommend RSJ's but I think that's for more substantial vertical breasts.

 

Question is what level of bricks would it be best to remove up to before fitting the brackets. It feels like if they are taken out right up to the junction then the bricks are all keyed into the main left column and the brackets would barely be doing anything.  Also who advises on the size of brackets required? Would building control advise or do I need to employ a structural engineer too?

Thanks in advance,

Jack

 

 

 

 

 

 

 

[Jenki]

I'd be looking at about 10 course up, from where you can see.

"Doing nothing"  is an interesting point of view.  There's probably 500kg towards 1000kg  of Brick above ( we can't see the stack)., Granted it is tied in, but when you add wind loads to the stack etc it all adds up.

You wouldn't want 2 bricks dropping on you from Any height. Never mind 2 or 3 hundred.

Gallows brackets, plate and resin bolts for me, and don't forget to cap the top.

 

 

 

[Adsibob]

33 minutes ago, J Pearse said:

I know in many cases they now recommend RSJ's but I think that's for more substantial vertical breasts.

 

Question is what level of bricks would it be best to remove up to before fitting the brackets…  Also who advises on the size of brackets required? Would building control advise or do I need to employ a structural engineer too?

I’ve done a few chimney breast removals (two in my last place and two in our new place, and also helped my folks with one).  First things first, hire a structural engineer to design a solution for you. If the works are notifiable,  Building control will ask to see the SE’s drawings and calcs anyway. I would be very surprised if your SE allowed brackets. Brackets are really not best practice anymore, and haven’t been for decades. An RSJ is not expensive. You should be able to conceal the RSJ within the ceiling of the first floor / floor of the loft.

Edited October 21, 2022 by Adsibob

[Canski]

Why not remove the stack as well ? It’s just something else that will need looking after in the future. Start at the top like Fred Dibnah and drop it brick by brick down the flue. Have a goalkeeper at the bottom ready to load ( stack neatly) into the skip.  

[George]

Remove it completely if you don't want it. No point suspending a few tonnes of bricks and keeping a hole in the roof.

 

If you do want to keep the bricks, then unfortunately gallows brackets are unlikely to be viable. But get a structural engineer involved. 

 

Building Control used to be a bit more forthcoming with advice but after a few disasters then tend to ask for structural engineer's design (and insurance). 

[Mr Punter]

If this is a shared chimney stack it would be useful to see if your neighbour's has been altered.

[J Pearse]

So further info.. don't want to remove it as the left breast goes down to the lounge and we will be lining this with a flue and installing a log burner. Not to mention I'd rather not need to climb on the roof and remove 4x the total amount of bricks.

 

Also definitely wasn't suggesting I could leave it unsupported just thinking about the forces involved if I remove right up to the fork on the right side so the bricks are all keyed in it feels like the forces to counter are less than if I remove to a height that leaves several rows of bricks hanging.

 

Sounds like I need to talk to a structural engineer and get them to advise. 

[saveasteading]

23 hours ago, Adsibob said:

very surprised if your SE allowed brackets.

Did this in a daughter's  terrace house about 5 years ago.

Took maybe 2 hours, using stud and epoxy.

Gallows bracket installed where a previous owner had just cut out bricks,  only supporting the remaining chimney on some bits of wood on the joists.

 

I say remove as little as you can, as the chimney is part of the structure, including next door. The party wall will be 1 brick thick (225) at most and the chimney is a major part of the strength,

[Iceverge]

You're lightly looking at less than 1m2 of a gain in floor area for a whole lot of trouble. 

 

Something like stacking the dryer on top of the dishwasher or bolting a TV to the wall and removing the TV table would gain as much floor space for almost no cost.  

 

 

[Adsibob]

10 hours ago, Iceverge said:

You're lightly looking at less than 1m2 of a gain in floor area

In some places, that could add over £10k in value to a property!

[George]

I need to discuss with Gus the role of brackets. 

 

I'm not a fan of online calculations but this is a decent summary of the issues https://beamcalc.co.uk/gallows-bracket-calculations/

 

 

[Gus Potter]

On 21/10/2022 at 21:58, J Pearse said:

The 1930's semi we are moving into has a chimney breast in the dining room we are looking into removing.

 

On 23/10/2022 at 13:23, George said:

I'm not a fan of online calculations

Very much agree with George's take on this.

 

You could get a beam calc done online for say £150 quid. But the vast majority of the responsibility / liability will fall on you as the home owner to provide all the right information.. and if you are able to do that then you would be able to do the calculations yourself anyway. It's not just the "beam calculation" its how that the beam interacts with the rest of the building and making sure the remaining structure remains stable.

 

This chimney and gallows brackets.. it's not something I would entertain for the following reasons:

 

1/ Gallows brackets introduce a bending effect into the old walls. Walls in and around chimneys can look ok on the outside but the flue gasses often rot away the inside badly. Thus you have no idea as to how strong the masonry may be near chimneys. Often you can add extra true vertical load down the centre line of the wall to old wall and it is fine but as soon as you add a bending effect it will protest big style.

 

2/ You don't know what someone will do next door in the future.. they may have already done so and your gallows brackets will over stress the masonry locally as the flues are often offset.

 

3/ The chimneys act like piers / butresses to stop the party wall from buckling sideways.

 

4/ In a terrace of houses all these "extra" bits of masonry (chimney breasts, old cupboard walls / coal stores etc) add what we call " robustness" that contribute to stopping the whole terrace from moving sideways. If everyone chips away at this then the stability of the whole terrace can be called into question as this can lead to what we call disproportionate collapse. That is one reason why the councils have clamped down on gallows brackets and types of alteration that compromise the whole row of houses.

 

If it was me then I would first want to be clear what you want to do and then look next door.

 

There are are a couple of possible easy options here using some smallish steels. The steels don't need to be big as they don't carry a large amount of vertical load. But that small amount of "off centre" vertical load is enough to make the party wall very unstable as it introduces a bending force as well as ondinary vertical load.

 

One option is along the lines of this. Run a beam from the front to rear elevation just inboard of the brick flue inside face. Then run a short stub back to the centreline of the party wall. You then build up over the stub and pack to support the bit of the flue above.

Here you have the practicable problem of how do we get a long beam into the roof space! You can split it into two or three bits and join it together when you get it into the loft.

 

The other is to run a beam from the party wall back to an load bearing internal wall if you have one.

 

Then you need to work a bit of magic where you know you have spliced beams and that the joints will move when you load up the beam. There are a few easy tricks of the trade you can deploy here at low cost.

 

In summary I would say..

 

1/ Avoid gallows brackets.

2/ Talk to an SE. Once you get your head around it you may find that you can do more for no /little extra cost? That could offset the SE fee?

3/ Make sure you get access to next door and take photos in case you get the blame for cracks that are not your fault!

4/ If in England etc read up on the party wall act.

5/ If in Scotland.. talk to an SE.. we don't have the party wall act.. good in some respects.. awful in others.

 

Hope this helps

 

 

 

 

 

 

 

 

 

 

 

 

[saveasteading]

Or leave the chimney in place and find a use for it. A floral display perhaps, or storage. We only fitted the gallows bracket because the wall was already gone, and the chimney propped on the joists.

These houses work using the chimney as a major part of the structure and a ventilator. Doing a proper job will be disruptive and expensive.

Who knows what the next wave of buyers will think. Perhaps they will value the chimney or fear that it has been removed.

[J Pearse]

Got an SE to take a look and he has done some calcs for a beam to take the load on top of the brick walls (one external and one internal) in the loft.

 

Question is, the external wall has a joist that the roof rafters sit on which runs along the top of the external brick wall essentially blocking where the RSJ would sit.  It covers the whole width but theres a gap below it (between the joist and the bricks). How would you fabricate it so it can sit on the wall?  I'm assuming I can't cut the joist.  See pic!