Why support is critical
Removing a chimney breast on one floor leaves the upper sections (stack and any upper-floor breasts) unsupported. Support options: 1) gallows brackets — steel brackets bolted to the party wall, supporting the chimney remnant above (cheapest, £600–£1,200, but only suitable when party wall can take the load and neighbour consents); 2) steel beam — RSJ across the room supporting the upper chimney (more flexible, £1,400–£2,800, no party wall load concerns); 3) full stack removal — most expensive but cleanest. Structural engineer always required.
Party Wall etc. Act 1996
Most London chimney breasts sit on party walls — removal triggers Party Wall Act notices to the adjoining owner. Section 2(2)(a) — cutting into a party wall (e.g. for gallows brackets) — and Section 6 — excavation near a neighbouring building — both potentially apply. Minimum 2 months notice. Typical surveyor fees £1,200–£2,800 if neighbour appoints their own surveyor. Builderr coordinates surveyor and notices to avoid programme slippage.
Building control and full process
Building Regulations Approved Document A (structure) requires structural design and inspection. Submit a building notice or full plans application — typical fee £350–£700 in London. Process: structural engineer's design (£400–£800), party wall notices and award (£1,200–£2,800), strip-out and steel supply, careful demolition with debris management (mortar dust contains historic lime/cement dust — wet down and PPE), structural support installation, building control sign-off, plastering and reinstatement. Add 3–5 days for plaster cure and decoration.
