Chimney Breast Removal Cost London (2026 Guide)

Chimney breast removal cost in London by scope

Chimney breast removal is priced mainly by how many floors it affects, not by the room size, since the structural support required to hold up the wall and chimney stack above scales with the number of storeys being opened up. Removing a chimney breast on a single storey, most commonly a ground floor reception room while the breast is kept intact on the floors above, typically costs £1,500 to £5,000. Removing the breast on every floor, from the ground floor through to the loft, known as a full-stack removal, typically costs £3,000 to £7,000 or more, reflecting the extra floors of support work, making good and, in most cases, a larger steel beam specification to carry the load higher up the building.

The wide range within each band comes down to what the structural engineer specifies once they've assessed the wall and stack: a straightforward single-storey removal supported on gallows brackets sits toward the lower end, while a removal requiring a full steel beam, additional foundation work, or extensive plaster and decoration making good across a period property sits toward the upper end. A structural survey is the only reliable way to narrow the range for a specific chimney breast.

Why structural support is usually required

A chimney breast very rarely just disappears without something taking over the job it was doing. In most London terraces and semis, the chimney breast forms part of the load path for the floors and stack above it, even where it looks purely decorative from inside the room. Once the breast is removed, that load needs somewhere else to go, which is why structural support is required in the great majority of chimney breast removals, not just the more obviously structural ones.

Two approaches cover most projects. Gallows brackets, steel brackets fixed into the chimney breast wall on either side of the opening, are usually specified where the stack above is also being removed or is lightweight, and are typically the more affordable option. A steel beam (RSJ), spanning the full width of the former chimney breast and bearing onto the wall either side, is usually specified where the stack above is being retained, where the span is wider, or where the load from upper floors is greater. Which of these applies to a specific property is a structural engineer's decision, not a builder's judgement call, and it should be confirmed before any quote is finalised.

Building regulations: why sign-off is required

Chimney breast removal is structural work and falls under Part A (structure) of the building regulations, regardless of whether it's a single-storey removal or a full stack. That means the work needs either a building notice or full plans application submitted to building control, and a structural engineer's calculation showing how the loads above the removed breast are being carried, before work starts.

Building control will also want to inspect the work at key stages, typically once the opening has been formed and the beam or brackets are in place but before it's covered up by plaster or plasterboard, so the support can be checked while it's still visible. Skipping this step is a common and costly mistake: a chimney breast removed without building control sign-off can create real problems when the property is later sold, since conveyancing solicitors routinely ask for a completion certificate for structural work, and its absence can hold up or reduce the value of a sale years after the work was done.

Party wall considerations for shared chimney stacks

A large number of London's Victorian and Edwardian terraces were built with a shared chimney stack straddling the party wall between two adjoining properties, each side originally serving its own fireplace. Removing a chimney breast on your side of a shared stack is very likely to fall under the Party Wall etc. Act 1996, since the work affects a structure shared with your neighbour, even where your neighbour has no plans to touch their own chimney breast at all.

In practice, this means serving a party wall notice on the neighbouring owner before work starts, and, where they don't consent informally, appointing a party wall surveyor (or surveyors, one for each side, or one agreed surveyor for both) to produce a party wall award setting out how the work will be carried out safely. This process typically adds four to six weeks to a project timeline where it's needed, so it's worth checking whether your chimney breast is shared, and starting the party wall process, as early as possible rather than after a contractor has already been booked. Our property refurbishment London team can flag whether a specific chimney breast removal is likely to need a party wall notice as part of an initial survey.

What happens to the flue and stack above roof level

Removing a chimney breast at first or ground floor level doesn't automatically mean the chimney stack above the roofline comes down too, and the two decisions are often made separately. Where the stack above is being kept, either because it's still in use elsewhere in the building, shared with a neighbouring flue, or valued as a period feature on the roofline, the now-redundant flue needs to be capped and ventilated at the point where the breast has been removed, to prevent damp and condensation building up inside the disused flue.

Where the stack is also being removed down to roof level, the roof covering needs to be made good around the former stack position, which typically involves matching the existing tiles or slates and reinstating the roof structure and insulation at that point. This is roofing work as much as internal building work, and where a stack removal is part of the scope, it's worth having it assessed alongside the internal breast removal rather than as an afterthought, since the roof-level work affects both cost and the trades needed on site.

Full removal versus partial removal

How long does chimney breast removal take?

A straightforward single-storey removal, once building control and any party wall process are in place, typically takes one to two weeks on site, covering forming the opening, installing the beam or brackets, and making good the wall, ceiling and floor. A full-stack removal usually takes three to five weeks on site, reflecting the extra floors of work, though the building control and, where relevant, party wall process ahead of the on-site work can add several weeks before anything starts. Our construction company London team can sequence the structural engineer's input, building control application and party wall process in parallel where possible, so the on-site time isn't held up waiting on paperwork that could have been progressing earlier.