Chimney Breast Removal Calculations
From £395 — Priced by Scope
Removing a chimney breast is not the same job as a straightforward wall removal. The stack above still has to go somewhere. CEng MIStructE — Engineering Safety First.
Why a Chimney Breast Costs More Than a Steel Beam
A knock-through is a beam design. A chimney breast removal is a beam design plus a full load takedown of the masonry stack you are leaving in place above it — its self-weight, its eccentricity, and the wind load acting on the part that projects above the roof. It also needs a bearing and pull-out check where the new support engages the wall, and a specified propping and needling sequence so the stack is never left unsupported during demolition.
That is why the fee starts above our single steel beam price of £295. Any engineer quoting a chimney at the same price as a plain beam has not accounted for the retained stack.
Fee Bands
Single-Storey Breast Removal
£395
Breast removed on one floor only, with the stack above retained and supported on a new beam or lintel. No party wall involvement.
The most common case — a ground-floor or first-floor breast removed to reclaim room space.
Multi-Storey or Party Wall
£550
Breast removed across two or more floors, or the beam bearing lands in a shared party wall, or gallows brackets are proposed and must be justified by calculation.
Terraced and semi-detached properties where the stack is shared with a neighbour.
Full Stack Removal
£695
The entire stack removed on all floors including above roof level — covering roof making-good, the rafter and purlin interface, weathering, and the lateral stability of the remaining roof structure.
Complete removal of a redundant chimney, top to bottom.
Retrospective Certification
£450 + site visit
A chimney breast already removed without engineering input. Assessment of what is actually there, plus certification for Building Control regularisation or a conveyancing enquiry. A Tier 1 site visit (£250) is mandatory and cannot be waived — this work cannot be done from photographs.
Buying or selling a property where previous work has no paperwork.
All prices are final — no VAT is added. Site attendance is charged separately under our Site Attendance schedule, except in Band 4 where a Tier 1 visit is mandatory and priced in above.
A Warning About Gallows Brackets
Gallows brackets — steel brackets bolted to the party wall to carry the retained stack — are increasingly rejected by Building Control. They rely entirely on the condition and quality of old masonry, which frequently cannot be verified. Where gallows are proposed, they must be justified by calculation and by pull-out testing of the fixings before completion.
Our recommendation in most cases is to design a supporting beam from the outset. If Building Control rejects a gallows scheme after the fact, the beam redesign is chargeable — and the abortive work is avoidable.
Party Walls
In a terraced or semi-detached property, the chimney stack is usually shared with your neighbour and sits within the party wall. Cutting a beam pocket into it engages Section 2 of the Party Wall etc. Act 1996, and you will need to serve notice on your neighbour.
We provide the engineering design. We do not serve party wall notices, act as a party wall surveyor, or produce the Award — you appoint a party wall surveyor separately for that.
What the Fee Does Not Include
- Building Control application and inspection fees, payable to your local authority or approved inspector
- Party Wall etc. Act 1996 notices, surveying, and the Award — you appoint a party wall surveyor
- Site attendance — charged separately under the Site Attendance schedule. Band 4 is the exception: its mandatory Tier 1 visit (£250) is additional to the £450 design fee, giving a £700 minimum.
- Builder's costs, temporary propping supply and erection, demolition, and making good
- Asbestos survey or removal, and flue or gas appliance disconnection
- Any works to a neighbour's retained flue
- Redesign where Building Control rejects a gallows-bracket scheme
What You Receive
- Full structural calculations, signed by a Chartered Engineer
- Load takedown of the retained stack above
- Beam sizing, bearing and padstone design
- Specified propping and needling sequence for the demolition
- Building Control-ready PDF
- Plan and section drawings
Planning a Chimney Breast Removal?
Send us photographs, your dimensions, and a floor plan. We will confirm the band and a fixed fee before any work begins.
Request a Fixed Quote