First floor chimney breast removal

[Maatz123]

Hi all,

After some help and insight.

In the process of removing 1st floor chimney breast in bedroom (not ready to remove ground floor breast in lounge underneath yet).

Stack is supported in loft by beam and I've already removed the breast itself (alot harder and messier than expected!)

Now in the bedroom floor I am left with what looks like a concrete slab and remaining flu going through to the lounge breast.

I need to remove all of this so I can replace joists and floorboards ready for carpet etc.

Flu side looks straight forward, its just bricks, but unsure what I'm dealing with with the concrete slab and unsure best way to tackle it.

Anyone got got any experience with this and can provide advice and insight?

 

[Ivor Windybottom]

It needs to go and be replaced with floorboards - either now, or when you do the room below. I'd just board over it to make it up to (roughly) floor height for now, do a proper job when you do the room below.

If you were to do it now then you'd end up with a hole in the chimney breast and ceiling of the room below until you're ready to remove that section.

It should go without saying... you'll need to check whether the joists are supported by the chimney before removing it. Now is a good time. The same goes for the ceiling above the room you're working on.

Unless it adjoins your neighbour's chimney, removing it up to the sky is preferable to resting it on a joist. You'll need calculations etc for this, if you haven't already.

 

[stuart45]

There's a few different methods of supporting the upper floor hearth.
Can be a reinforced slab cantilevered into the brickwork.
Older properties sometimes had a brick trimmer arch under it.

 

[Ivor Windybottom]

The brickwork below is going to be removed at some point. So it needs to become a suspended floor at some point, the question is whether that point is now or when the chimney breast below is removed.

I'd suggest the latter, just make good over the concrete for now.

Having said that, if it is cantilevered from the chimney then its counterbalance (the chimney breast above) is no longer there. So perhaps it needs removing now, as if you stand on it then it may tip.

I just know I'd have thought all this through before I'd got here!

 

[stuart45]

Thinking ahead is always the best. One of the problems in the construction trade is that you can never be sure about how things were built if you can't see them.
For example, the original builders could have left out the rebar and just relied on the trimmer joists to wedge it in place. It's surprising how easy it is to knock some of them out.

 

[cdbe]

When the joists run parallel to the breast like that it's worth investigating whether the joist carrying the hearth slab has been notched and the one against the wall trimmed - without the CB there it's likely the floor will be loaded more.

 

[^woody^]

Take out what you can within the floor, fit some timber trimmers (min 50x100) and board it.

That allows you to finish the room and not need to disturb it again later

Remember to seal the wall before plastering, to provide a barrier to combustion chemicals.

 

[Maatz123]

Hi all,

I just thought I would close the loop on this thread as someone in the same position might find it useful.

Attaching some photos that will hopefully make sense of my inexperienced/DIY terminology.

So removing more floor boards I could see that the hearth slab was enclosed in timber trimmers around the side, nothing on bottom, was literally sitting on top of lath and plaster.

Stuck a sheet of plasterboard on the lounge ceiling below, expanding foam round edges to prevent dust getting through, and even stuck a couple props underneath as I could envision the slab falling through the ceiling!

Lounge ceiling doesn't look pretty but its a renovation house so its natural for us. As mentioned will be removing breast in lounge later, overboarding ceiling and plastering so will all be good in not too distant future.

breaking out the hearth slab was HARD work, it was solid and felt like I was never going to get it out, but little by little, rubble sack by rubble sack it was gone.

After, joist hangers, 2x joists and chipboard on top and as if it was never there.

This might of been reckless, and if so I got away with it!

 

[Ivor Windybottom]

Brilliant work, very impressive that you managed to do that without breaking the plasterboard and I guess without much dust either.

It looks like it was sort-of cantilevered from the chimney, but without rebar and with a blazing fire cracking it up then it doesn't look like it was held up by very much.

Don't knock yourself, DIYers often make up for a lack of experience with a lot more care taken as I hope I do.

Does it have enough joist at the front edge for your new boards? It's hard to tell from the perspective.

I'm a big fan of chimney removal, they're horrible damp, draughty stinking things. Have got rid of 2 of our 3 so far, the last will go one day. I just wish all our neighbours thought the same!

 

[Maatz123]

Brilliant work, very impressive that you managed to do that without breaking the plasterboard and I guess without much dust either.

It looks like it was sort-of cantilevered from the chimney, but without rebar and with a blazing fire cracking it up then it doesn't look like it was held up by very much.

Don't knock yourself, DIYers often make up for a lack of experience with a lot more care taken as I hope I do.

Does it have enough joist at the front edge for your new boards? It's hard to tell from the perspective.

I'm a big fan of chimney removal, they're horrible damp, draughty stinking things. Have got rid of 2 of our 3 so far, the last will go one day. I just wish all our neighbours thought the same!

Thank you

There was a quite a bit of dust falling through to the lounge (wife not happy!) before I foamed the edges of the board.

There’s probably not enough joist at the front for a permanent solution, ok for now before I do final fixing but I’ll probably cut those floor boards back to reveal more joist or sister the joist or both probably cause I over think things.

It was a tough and messy job but I’m glad I did it, it’s made a big difference to the size of the bedroom and means we have for length wardrobe across the wall now