We're called out fairly often to put right chimney removals done without proper support, usually spotted as a crack opening up in the bedroom above or a slight bounce in the floor near where the breast used to be. Doing it properly the first time costs less than doing it twice.
What's actually above the breast you're removing
Before any decision on support method, we establish what the stack is carrying. A single-storey removal on a ground floor breast with a stack continuing through a bedroom and out through the roof means that bedroom's chimney breast, and the stack above the roofline, still need a permanent home for their weight. Removing a breast on the top floor under a stack that stops at roof level is a much smaller job structurally, though the exposed stack above still needs weathering.
It's common in Kent's Victorian and Edwardian terraces and semis to find a shared stack serving two adjoining properties, which brings the party wall into play even for what feels like a straightforward job.
Gallows brackets versus a steel beam
Gallows brackets are steel angle brackets bolted into the party wall or masonry either side of the removed breast, supporting the remaining chimney breast above like a shelf bracket. They're a recognised, building-control-accepted method for supporting a single breast above where the wall either side is sound masonry capable of taking the load.
A steel beam spanning the opening, picking up the load from above and transferring it down to padstones either side, is the other common route, and is usually specified where the load above is greater — a full stack continuing up two floors, wider openings, or where the masonry either side isn't in good enough condition to trust with gallows brackets alone.
Which one is right isn't a preference call — it comes down to the load an engineer calculates and what the existing wall can actually support. We don't recommend gallows brackets by default just because they're cheaper; if the numbers point to steel, that's what goes in.
- Gallows brackets — bolted steel angles either side, load-bearing masonry required
- Steel beam and padstones — for heavier loads or unreliable existing masonry
- Both need a structural engineer's calculation before installation, not after
Building control and the paperwork
Removing a chimney breast is building work controlled under the Building Regulations because it affects the structure of the building. It needs either a full plans or building notice application, and an inspector will want to see the engineer's calculations and sign off the support before it's covered up and again once complete, with a completion certificate issued at the end.
This is one of those jobs where skipping the paperwork causes real problems later — mortgage lenders and buyers' solicitors routinely ask for the building regs completion certificate for chimney breast removals when a property is sold, and without it you can find yourself paying for indemnity insurance or a retrospective inspection at exactly the wrong moment in a sale.
When you need a party wall agreement
If the chimney breast is built into or against a shared wall with a neighbouring property — as most terraced and semi-detached stacks are — the Party Wall etc. Act 1996 applies, because the work affects a wall the neighbour has an interest in. That means serving formal notice before work starts, and either getting written consent or appointing a surveyor (or a shared one) to agree a party wall award.
This catches people out because it feels like it's happening entirely inside your own house. The test isn't whose room the fireplace is in, it's whether the wall or stack is shared or adjoining. We flag this at quote stage on any semi or terrace so there are no delays once a start date is booked.
Making good above and below
Once support is in and signed off, the chimney breast recess is usually filled to match the wall line, plastered, and decorated. Above, if the stack continues, the recess in the room upstairs is treated the same way, and any exposed flue needs capping properly at roof level if the fireplace below is no longer in use — with ventilation left in place to stop condensation building up inside the redundant flue.
It's worth deciding at the same time whether you want the fireplace opening retained as a feature downstairs even after removing the breast above, since that changes where the steel or brackets need to sit.
What it typically involves on site
A survey and engineer's calculation come first, then building control notification, then the structural work itself — usually a day or two for the support installation and breaking out the masonry, followed by making good, which takes longer depending on the finish required. Dust and disruption are more than a lot of people expect, since breaking out brick and flue lining is a genuinely dusty job, and we sheet and screen the work area accordingly.
Common questions
Can I remove a chimney breast on just one floor and leave the rest of the stack?
Yes, this is very common — removing a ground-floor breast while leaving the stack running through the floors above, or vice versa. Whatever remains above the removed section still needs permanent support, so the calculation has to account for exactly what's left standing.
Do I need planning permission to remove a chimney breast?
Usually not, since it's normally treated as internal structural work rather than development requiring planning permission. It's building regulations approval you need, not planning consent — though if you're in a listed building, listed building consent may apply even to internal changes.
What happens to the chimney stack on the roof if I remove the breast?
If no other fireplace uses that flue, the stack above roof level can sometimes be removed too, which needs its own structural consideration for the roof structure and weathering. If it's left standing — often required in conservation areas for street appearance — it needs a proper cap and ventilation.
How do I know if gallows brackets are strong enough for my situation?
You don't decide this yourself — a structural engineer calculates the load the remaining masonry above will impose and specifies bracket size, fixing depth and spacing, or tells you steel is needed instead. We arrange this as part of the job.
What if my neighbour won't agree to the party wall notice?
If they don't respond or dispute it, a party wall surveyor (either agreed jointly or one each) is appointed to produce an award setting out how and when the work can proceed. It adds time, so serving notice early — ideally before you're ready to start on site — avoids the removal date slipping.