Chimney breast support

towering over my bedroom.

Why do you say that?

The top is simply a stepped brick detail, once removed to a suitable height it will be less than 20 course of brick.

If your diagram is fairly accurate it looks like over 300 bricks, knocking on a ton, balancing on two central 9" x 4" contact points on the party wall.

The BCO would likely recommend using gallows brackets bolted to the wall to support the remaining mass, I came up with this design as the load is central over the party wall, the cantilever effect would counter balance each side thus be stronger than gallows with the addition of not relying on bolts in the wall.

I could easily add additional steals and plate material across the width?

Something like this?

Yeah, I'm not sure that method of support would not work for this Chimney, mine is a shared construction over the party wall but it is built in the opposite direction to the one you pictured, so essentially the area on my side for example is 3 foot by 3 foot, the entire chimney being 6 foot by 3 foot

Have you checked the BCO will take gallows brackets? I ask because some prefer more involved supports, some don't.

What does the BCO recommend?

Regards Richard

right angles to the line of the chimney stack?

Anyway, I think you're going to need a structural engineer at some point

Yeah, it is as you thought it looks the wrong way around on the wall but it is actually the way it is.

What thickness is the party wall? I ask because some houses really did use the stack to buttress the wall.

The problem with brackets is the wall may not like the load and some BCO prefer RSJ/UB to some other supporting wall to provide a somewhat more stable solution.

Or at least some professional advice, if only to keep the BCO happy.

Personally that amount of brick work perched on a couple of "steal" beams on top of a wall doesn't look stable enough, strong enough provided all of the base of the stack is supported but still able to wobble. Beams with gallows brackets under them would be better IANASE.

Hi Dave

I have been considering adding Gallows to the base of the steels if only to give an area of steel against the party wall, and enable a sufficient fixing, I don't think it would require more support than two 8*8 steels but maybe more stability than a centre balancing cantilever, the load we are talking about is 800Kg.

Cheers

With brackets, what happens if the neighbour decides to remove their part of the stack above the roofline when having a re-roof? IE, reducing or removing the counterbalance to your stack on the partywall?

That would be a problem with or without brackets. It would also look bloomin' awful.

It does :-)

It is something bizarre that gets done with some reroof companies - the same ones that stand in the driveway holding up the sarking felt and tearing it for everyone to see, repeatedly, throughout the day, and the next day.

I have wondered how they got the RSJ in without it toppling over, and it's an enormous stack (8 or 12 flues, IIRC).