Using gallows brackets to safely remove a chimney breast.

One way to safely remove a chimney breast from a property is by using gallows brackets.

Load bearing gallows brackets are ideal for supporting a chimney stack in the loft. For example, when you're removing the chimney breast from the ground floor and first floor.

Chimney breast removal is something we have to do on a regular basis here at HYPE Building. Particularly in HMO conversions where floor space is crucial.

The whole job is in the video further down this page, and every photograph here is a frame from it.

A gallows bracket is a right-angled triangular bracket, rather like a shelf bracket.

Two gallows brackets and a metal plate support the chimney stack. A bracket sits either side of the stack with the top of each bracket being the exact depth of the stack.

A metal plate bridges the two brackets and sits directly beneath the bricks it is supporting.

This is the most common version of the question, and it is the one where the answer changes.

If the breast comes out on the ground floor only, everything above it stays: the first floor breast, the stack in the loft, and the chimney above the roof. That is a lot of masonry, and it is considerably more weight than gallows brackets are intended to carry. A steel beam is normally the right call.

Gallows brackets come into their own on the job in the video, where the breast has been taken out on both floors and the only thing left needing support is the stack in the loft.

So the honest answer to whether you can remove a chimney breast downstairs only is yes, but not usually on brackets. What decides it is how much is left above, and that is a calculation rather than an opinion.

0:23 · Before removing a chimney using gallows brackets, a structural engineer will need to assess the weight of the load that the brackets will support.

2:41 · The gallows bracket itself looks like a shelf bracket. Its depth is identical to the depth of the chimney you're removing.

3:54 · A structural engineer will design the gallows brackets. This ensures they are the correct size and thickness to support the remaining chimney stack. Building Control will then need to sign off the work. They will ask to see the drawings from the structural engineer. Thus, giving the reassurance that the work is correct and safe.

5:03 · You'll need a Party Wall Notice. Because it's essential to inform your neighbour that you're removing your chimney breast.

5:58 · John describes how removing the chimney breast impacts on the structural integrity of the party wall.

7:11 · It's important to fill any gaps in the mortar to prevent the potential release of harmful gases from next door.

At this particular property, a HMO conversion, we used gallows brackets.

That's because the chimney breast has been removed on both floors of the property. And only the remaining chimney stack in the loft requires support.

If the chimney breast is being removed on the downstairs floor only, a steel would be a better option. Because the remaining weight requiring support is much greater.

So, in a nutshell, gallows brackets are suitable when a smaller weight is being supported.

However, there is a caveat.

As John explains in the video, a lot depends on whether your neighbour has already removed their chimney.

If they have, making any structural alterations your side may place the party wall under too much strain. Two breasts removed from opposite faces of the same wall is a very different structure from one.

Hence the reason you need the opinion of a structural engineer. They will tell you the correct approach to take.

You will also need a Party Wall Notice, because it is essential to inform your neighbour that you are removing your chimney breast. And when the breast comes off, any gaps left in the mortar need filling, to prevent the potential release of harmful gases from next door into your rooms.