Removing a chimney breast: costs and hiring a builder

Removing a chimney breast needs structural engineering, Building Regulations approval, and often a party wall agreement — sort these before hiring a builder.

CB-01What removing a chimney breast involvesA chimney breast is the part of the chimney that sticks into the room; the stack is the part above the roof. You can remove the breast on just one floor, on every floor, or remove the whole chimney including the stack. If you remove a breast but leave anything above it standing, that part needs full structural support — usually a steel beam built into the wall.

CB-02Check what needs permissionThis is structural work, so it always has to meet Building Regulations, whatever floor the breast is on. If the chimney sits in a wall shared with next door — common in semis and terraces — the Party Wall Act usually applies as well. Planning permission is rarely needed unless the house is listed or you're removing the stack itself in a conservation area.

RULES

KNOW THE RULES

Structural alterations like this must comply with Building Regulations Part A. Shared chimney walls usually bring the Party Wall Act 1996 into play. See HomeGraft's 'Know the rules' guides on Building Regulations and the Party Wall Act.

CB-03Hire a structural engineer first — before any builderGet a structural engineer to inspect the chimney and work out what's supporting it above the point you want to clear. They'll specify a steel beam size and any extra support needed, and produce calculations that both Building Control and your builder will need. Do this before getting builder quotes, so every quote prices the same job instead of guesswork.

CB-04Serve a party wall notice if the chimney is sharedIf the chimney breast is built into a wall shared with your neighbour, you must serve a Party Wall Notice at least two months before work starts. If your neighbour doesn't agree, you'll need a surveyor — sometimes one each — to produce a Party Wall Award before the builder can begin. This applies even if you're on good terms with your neighbour.

RULES

KNOW THE RULES

Serving notice under the Party Wall Act 1996 is a legal duty, not a courtesy. Skipping it can delay or stop the work. See HomeGraft's 'Know the rules' guide on the Party Wall Act.

CB-05Get quotes — what a good one should containEvery quote should be based on your structural engineer's specification, not a guess. It should list the steel beam and its installation, making good to walls, ceilings and floors, removing or capping the stack if that applies, scaffolding if work is needed above roof height, waste removal, and who is submitting the Building Regulations application and paying the fee. Get at least three quotes, all priced against the same engineer's spec, so you're comparing like for like.

CB-06Questions to ask, and red flagsAsk who is submitting the Building Control application and when, whether they've worked from your engineer's drawings, what their public liability insurance covers, and for a reference or photos of a similar completed job. Be wary of anyone who quotes without seeing the engineer's spec, asks for full payment upfront, or waves off Building Regulations as 'not a problem' without saying how they'll meet them.

CB-07Realistic costs and timescalesFor an average three-bedroom house outside London, removing a breast on one floor only typically costs £1,500 to £3,000. Removing the full chimney, breast and stack, usually runs £3,500 to £7,000 or more. On top of that, budget £300 to £600 for the structural engineer and £700 to £1,500 or more for party wall surveyors if needed, plus £500 to £1,500 for scaffolding if work reaches roof level. London and the South East usually run higher. Full-height removal, roof and re-tiling work, and awkward access push jobs to the top of the range. Expect 1 to 2 weeks for the engineer's report, a statutory 2-month minimum wait if a party wall notice is needed, 3 days to 2 weeks for the building work itself, and a further few weeks for Building Control to finish sign-off.

CB-08Get Building Control sign-offOnce the work is finished and inspected, you need a completion certificate from Building Control. Without it, you can run into problems proving the work was done safely when you come to sell the house. Either the builder or you must log the job with your local council's Building Control team before work starts — check which, and get written confirmation it's been done.

RULES

KNOW THE RULES

A completion certificate from Building Control is required for structural work like this under the Building Regulations. Missing paperwork can cause problems at resale.

CB-09What commonly goes wrongThe most common problem is a builder removing a breast without proper structural support in place first, which can cause cracking or, in serious cases, sagging or collapse above. Other recurring issues: work starting before Building Control is notified, the party wall process being skipped, and poor weatherproofing at roof level after stack removal, leading to leaks. If other rooms still use a fireplace on the same flue, removing a breast lower down can also disrupt ventilation — raise this with your engineer and builder early.

CB-10If you live in Wales, Scotland or Northern IrelandIn Wales, Building Regulations and the Party Wall Act both apply, much as in England. In Scotland, there's no Party Wall Act — instead you need a Building Warrant from your local council before work starts, not after, and shared wall issues are handled under common law and title deeds. In Northern Ireland, Building Regulations (NI) apply but the Party Wall Act doesn't, so check with your local council about shared wall issues instead.

RULES

KNOW THE RULES

Scotland requires a Building Warrant before work starts, under a different system to England and Wales. Northern Ireland follows Building Regulations (NI) and does not use the Party Wall Act.

KNOW THE RULES

Before you start: Do I need approval to remove a chimney breast? · Do I need a party wall agreement?

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