London Build Cost Index
The £/m² you can put in front of a client at Stage 1 without getting caught out later. Real London rates by typology and spec tier — not a paywalled national average, and updated every month.
London residential build costs held broadly flat through Q2, with the pressure sitting in fabricated steel and aluminium glazing rather than the wet trades. Labour remains the swing factor — 40–50% of a typical extension — and good trades are booking 8–10 weeks out for a summer start. If you are pricing a Stage-2 feasibility this month, budget the structure and glazing generously and keep contingency honest.
| Project type | Minimalist | Balanced | Signature |
|---|---|---|---|
| Loft conversionDormer / hip-to-gable, incl. structure & stair | £1,800 | £2,400 | £3,300 |
| Rear extensionSingle-storey, incl. glazing & finishes | £2,400 | £3,100 | £4,400 |
| Side returnInfill return, incl. rooflights | £2,200 | £2,900 | £4,100 |
| Wrap-around extensionL-shaped rear + side | £2,700 | £3,400 | £4,700 |
| Double-storey extensionTwo-storey rear/side | £2,600 | £3,300 | £4,600 |
| Full house renovationWhole-house strip & refit | £1,200 | £1,900 | £2,800 |
| Flat refurbishmentApartment strip & refit | £1,300 | £1,800 | £2,600 |
| New buildSingle dwelling, shell to finish | £1,800 | £2,400 | £3,200 |
| Loft + renovationCombined scope, shared prelims | £2,200 | £2,800 | £3,800 |
| Extension + renovationCombined scope, shared prelims | £2,900 | £3,400 | £4,700 |
| Loft + extension + renoWhole-house transformation | £3,000 | £3,800 | £5,000 |
Indicative £/m² of construction works, ex VAT, Outer London base. All-in rates — nothing is added on top except VAT (20% standard; 5% for qualifying conversions; 0% for a new dwelling). For a line-by-line elemental plan on your actual scheme, use the cost calculator.
Adjust for the borough
Multiply the base £/m² by the zone factor.
Material moves this month
What’s pushing the numbers around.
Real London build costs, every month.
The figures you need for a Stage-1 client conversation — from a live London contractor, not a paywalled national dataset.
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