Renovation calculator · London · 2026
Renovation cost calculator for London.
London renovation costs run materially above the BCIS national mean for three structural reasons: labour day-rates (London electrician/plumber rates roughly 25% above the FMB national mean), site logistics (skip permits, parking suspensions and waste-disposal costs that don't exist outside the M25), and planning friction (Article 4 directions covering most Inner London boroughs, plus dense Conservation Area coverage). A typical Inner London structural renovation of a 3-bed semi runs £245,000–£312,000 ex-VAT including a 10% contingency. Prime Central postcodes (W1, SW1, SW3, SW7, NW8, W8) add another 10–15% on top of that.
Regional uplift vs national mean: +20% to +35% · BCIS Q1 2026 derived
Typical projects in London 2026
Per-m² and per-project mid-range bands for London, derived from BCIS Q1 2026 with the city’s specific uplift factor applied. Ex-VAT, including contingency and labour at local FMB day-rates.
| Project | Mid-range £ | Range in London |
|---|---|---|
| Kitchen renovation (full strip + replace) | £32,500 | £18,500 – £72,000 |
| Side-return extension (terraced) | £82,000 | £55,000 – £125,000 |
| Loft conversion with rear dormer | £72,500 | £52,500 – £108,000 |
| Full electrical rewire (3-bed) | £11,500 | £7,500 – £18,500 |
| Replacement timber sash windows | £42,000 | £28,500 – £85,000 |
BCIS Q1 2026 + FMB 2026 + ONS COPI, restated for London. Ex-VAT, 10% contingency. Excludes professional fees.
Most Inner London boroughs operate Article 4 directions that withdraw Permitted Development rights from defined geographic areas — Hackney, Islington, Camden, Westminster, Kensington & Chelsea, Wandsworth, Tower Hamlets, Lambeth and Southwark all have extensive Article 4 networks in 2026. The practical effect: even routine rear extensions and rear dormers that would be PD elsewhere need a full householder planning application in London. Add £258 (rising to £293 from October 2026) for the application fee, plus £1,800–£4,500 for architect drawings, plus 8–10 weeks for the planning decision before works can begin. Pre-application advice from the borough costs £200–£800 and is almost always worth the spend.
Run a full estimate for your London project
Five short steps, three spec tiers, itemised breakdown including the +20% to +35% uplift for London. Free, no sign-up.
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Long reads
Want the reasoning behind the London numbers?
The cost guide explains where the underlying BCIS + FMB ranges come from. The AI guide covers how we tested Claude against a chartered QS on a real Inner-London property — useful context for any UK renovation, including London.
Renovation cost · 14 min
How much does it cost to renovate a UK house in 2026?
BCIS Q1 2026 + FMB data. Cost-by-scope / spec / region / room tables, the eight hidden costs nobody quotes for, and the VAT treatment that catches 4 in 10 homeowners.
Read the guideAI · 12 min
Can AI estimate a UK renovation cost from a property photo?
We tested Claude Sonnet 4.5 vision against a chartered UK quantity surveyor on a real Inner-London semi. Where AI is genuinely useful and where it falls apart.
Read the guide