Key Takeaways
- Removing a chimney breast typically costs £1,500 to £5,000, with one floor at £2,200 to £3,250 on a steel beam, the usual route now, or £1,500 to £2,500 where gallows brackets are accepted, and two floors at £3,000 to £5,000 (MyBuilder and MyJobQuote, 2026).
- The stack above must be supported. A steel beam designed by a structural engineer (£300 to £700 for the calculations) is now the usual route, because LABC withdrew its standard gallows bracket detail in 2024.
- Gallows brackets are the exception, used only where the engineer and building control accept them, and they are refused where the party wall is unsound or the neighbour's breast already sits on brackets.
- The work needs Building Regulations approval and a completion certificate, but not planning permission, unless the house is listed, when listed building consent is needed even for internal removal.
- Stacks usually sit in the shared party wall, so expect to serve a party wall notice two months ahead.
A chimney breast can eat up valuable floor space in a tight London room, and removing it is a popular way to reclaim it. But it is structural work that must be done properly. Here is the cost, the rules and the process.
Is it worth removing a chimney breast?
Usually yes, if the room is tight and the fireplace is redundant. A Victorian breast projects roughly 300 to 500 mm into the room and is 900 to 1,200 mm wide, so you reclaim around 0.4 m² of floor per storey and, more usefully, you square the room off. In a 3 m by 3.5 m London bedroom that is often the difference between a wardrobe fitting the wall and not.
Two honest caveats. Removal does not automatically add value: a buyer's surveyor will look for the completion certificate, and unsupported stacks are a standard red flag on a homebuyer report. And the alcoves either side of a breast are frequently the best storage in the room. If it is only the fireplace you dislike, capping and plastering over costs a fraction of full removal.
How is the stack above supported?
A chimney breast holds up the stack above it, so removing the lower section means the upper part has to be carried on something new. There are three routes, and the structural engineer we appoint decides which applies. The steel beam is now the one to plan and budget for.
- Steel beam: a beam on padstones spanning between the walls either side, carrying the remaining breast and stack. This is the usual route now. LABC, the body representing local authority building control, withdrew its standard gallows bracket detail in 2024, and most inspectors now expect a beam unless the engineer can justify brackets.
- Gallows brackets: a pair of steel brackets bolted through the party wall to carry the remaining breast. Cheaper, but used only where the engineer and building control accept them in the defined circumstances below.
- Full removal: take the whole breast and stack out, top to bottom, and make good the roof.
Building control guidance notes published by London and county authorities including Harrow and Tendring typically allow gallows brackets only where the supporting party wall is at least 225 mm of solid brickwork in sound condition, the breast is no wider than about 1,200 mm, and the stack above is cut down to roughly 1 m above the roof line. Brackets are refused outright if the neighbour's breast on the other side of the same wall has already been removed and is itself sitting on brackets, because you would be hanging two chimneys off one wall. Thresholds vary, so check your own borough's guidance note before pricing the job.
Criteria from Harrow Council and Tendring District Council building control chimney breast removal guidance notes, 2024 to 2026.How much does chimney breast removal cost?
Expect £1,500 to £5,000 for most jobs, and up to £7,000 where the stack comes off the roof as well. MyJobQuote puts the UK average at around £2,500 in 2026. What drives the number is how many floors you take out, whether the engineer and building control accept brackets instead of a beam, and whether scaffolding is needed. Price the beam: it is the common case.
| Scope | Typical cost | Notes |
|---|---|---|
| One floor, steel beam support (the usual route) | £2,200 to £3,250 | Beam, padstones, propping, making good floor and ceiling |
| One floor, gallows bracket support | £1,500 to £2,500 | Only where the engineer and building control accept brackets |
| Two floors, ground and first | £3,000 to £5,000 | More propping and more making good |
| Full removal including stack above the roof | £4,000 to £7,000 | Roof retiled, leadwork renewed |
| Structural engineer's calculations | £300 to £700 | Brackets from about £300, beam designs from about £450 |
| Building control application | £300 to £900 | London boroughs sit at the top of the range |
| Scaffolding | £600 to £1,200 | Only where work goes above roof level |
| Skip hire, 6 to 8 yard | £250 to £400 | Chimney rubble is heavy; add £30 to £80 for a road permit |
Do you need building control and a party wall agreement?
You need Building Regulations approval for both, and a party wall notice in most terraces. You do not normally need planning permission for internal removal, but if the property is listed you need listed building consent even for internal work, and taking a stack down in a conservation area or under an Article 4 direction can need permission because it changes the roofline. Our listed building guide covers that.
On the party wall side, chimney stacks are almost always built into the shared wall, so cutting into it or bolting brackets to it is notifiable work under the Party Wall etc. Act 1996. You, as the building owner, serve a party structure notice (or your surveyor does it for you) at least two months before starting; we supply the drawings and programme the notice needs and build to any award. Your neighbour has 14 days to reply and silence counts as dissent. If they dissent, surveyors are appointed and a party wall award typically costs £900 to £2,700 with one agreed surveyor, or £1,800 to £5,400 where each side appoints its own, paid by you.
Notice periods from the gov.uk Party Wall etc. Act 1996 explanatory booklet; surveyor fees from HomeOwners Alliance, 2026.How long does chimney breast removal take?
A single-floor removal is 3 to 5 days on site, but allow 4 to 8 weeks overall once calculations, building control and party wall notices are counted, and longer if a neighbour dissents.
- Survey and engineer's design, confirming the support method and the party wall's condition.
- Building control application and party wall notices served in advance.
- Sweep and cap the flue, and protect the room. Soot goes everywhere otherwise.
- Temporary propping to the breast and the floor above.
- Breast taken down in sections from the top of the run downwards.
- Beam fitted on its padstones (or brackets, where accepted), bearings bedded, and the remaining breast rebuilt onto it.
- Building control inspection with the support exposed.
- Making good: floor, ceiling, plaster, skirting and decoration.
What goes wrong, and how to avoid it
- Sealing the flue airtight. A capped chimney with no airflow condenses inside and pushes damp and salt staining through the plaster. Cap the pot with a vented cowl and fit an air brick or vent low down so the flue can breathe.
- Exposing the neighbour's flue. In a shared stack the two flues can be a single brick apart. Break through and you can leave your neighbour's smoke venting into your room. The wall has to be rebuilt and parged properly.
- Soot and tar bleeding through. Old flue brickwork is loaded with salts that ghost through fresh plaster within weeks. It needs a salt-resistant render coat or a membrane, not another skim.
- Forgetting the constructional hearth. The concrete hearth in the floor comes out too, and the joists and floor need making good properly rather than boarding over the hole.
- Roof left half finished. Where the stack comes off, the tiles, battens, felt and leadwork all have to be reinstated. Redundant flashing left in place is a reliable source of leaks.
Getting it done
We appoint the structural engineer, who designs and sizes the support; we install it, and building control inspects it and issues the completion certificate. The party wall notice is served by you as the building owner, or by your surveyor, and we give you the drawings and programme it needs and build to the award, as set out on our party wall work in London page. See chimney breast removal in London, or read our related guides to RSJ installation and load-bearing walls and knocking two rooms into one. For a free quote, contact us or call 07472 424 226.