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OT: Building help (Chimney breast)
PSpirine - 22/9/15 at 04:29 PM

Great knowledge of LocostBuilders, I need your help.


Re-doing the gf's bathroom at the moment. It's a victorian terrace, which has a chimney breast in the bathroom. The fireplaces on that side of the house aren't used (Chimney is capped off), so we want to open up the breast as an alcove in the bathroom.

The fireplace has been opened up with a lintel in the bathroom (see picture), but what we want to do is get rid of the two flue stacks in the middle.


Most times that a chimney breast is removed, the whole thing is taken out, hence you need to support the entire thing either on RSJ/gallows brackets etc.


In this case, it should be much simpler, as we're keeping the vertical chimney breast sides that tie into the wall, and only want to remove the bits below the lintel (100cm opening, shaded blue in the picture) and the two flue stacks (shaded green in the picture). The side walls of the stack remain, and run all the way through the house to the basement.


The flue stacks are 225mm (brick length) deep, and are occasionally tied into the front face of the chimney breast and into the back wall - they start to go across diagonally about two bricks above the ceiling.


So, what do I need to do to prop up the upper flue bricks (total height of them approx 2m from ceiling to top of chimney through the roof)?

If I'm honest, given that it's tied into the front face and the rear wall, I'm pretty certain that if I removed the flue bricks from the room, it wouldn't go anywhere as it's corbelled into both the front and rear walls. However, I want to do this properly, so as to satisfy any inspector.


My initial thought was to simply get a 425mm long x 100mm wide piece of 6mm steel plate, and lay it rest it onto a brick one brick above the lintel, going from the front wall, straight into the back wall of the house and fill with mortar, so that the flue rests on that. That way it's tied into both walls with the load spread across both. Do that for both the flue stacks.

I could get gallows brackets (225mm long) made from 5mm angle and support the flues on those, but in my head that isn't actually any better from a load carrying capability, as it would be tied only into the rear wall.




rpm - 22/9/15 at 05:14 PM

tbh an opening of that depth isn't going to go anywhere when you remove the brick, but for piece of mind your idea of steel is fine or you could insert a short length of lintel above the existing one into the rear wall, I assume you will be closing of the finished opening to prevent dust/debris dropping

[Edited on 22/9/15 by rpm]


PSpirine - 24/9/15 at 09:32 AM

Thanks, will put steels in on the bricks. And yes, the opening is getting covered up. There's an air brick for each of the flues at the top below the chimney cap so it's got ventilation, so shouldn't have any issues!


DIY Si - 28/9/15 at 07:30 PM

Don't make that mistake, a chimney should be vented top and bottom! Just one at the top won't ventilate the lower half where any cold/wet air will hang.


hizzi - 29/9/15 at 06:48 AM

considering the house is terraced be wary of the chimney splitting and being shared half way up with a neighbour, it shouldnt be but we do come a cross them from time to time and as someone else said it needs vented top and bottom