Building Costs
London 2025
We are highly competitive. With SuperBuilder, you can rest assured that our quotation will be the most detailed. We can beat any respectable builder's quote — especially if you have an exciting or particularly challenging project. We always provide a professionally prepared quotation with a guarantee that there will be no hidden charges.
2025 London Cost Guide
Indicative costs based on typical London projects. All figures exclusive of VAT. Final price depends on specification, access, and site conditions.
| Service | Typical Range | Notes |
|---|---|---|
| Single-Storey Rear Extension | £35,000 – £80,000 | Typical 20–30m². Structural, plumbing and electrics included. Kitchen fit-out extra. |
| Double-Storey Extension | £65,000 – £130,000 | Adding ground and first floor accommodation. Significant value uplift. |
| Loft Conversion (Dormer) | £45,000 – £75,000 | Full dormer with en-suite. Includes staircase, insulation, and boarding. |
| Loft Conversion (Hip-to-Gable) | £55,000 – £90,000 | Maximum usable floor area — our most popular loft type. |
| Full House Refurbishment | £500 – £1,500 / m² | Strip-out, replastering, rewiring, plumbing, new joinery and decoration. |
| Bathroom Refurbishment | £8,000 – £25,000 | Full suite replacement including tiling, plumbing, and electrics. |
| Kitchen Installation | £12,000 – £40,000 | Supply and fit. Structural changes, plumbing, and electrics included. |
| Basement Conversion | £80,000 – £200,000+ | Underpinning, tanking, waterproofing, fit-out and party wall fees. |
| Office Refurbishment | £40 – £120 / m² | CAT A shell-and-core to full CAT B occupied fit-out. |
| New Build (per m²) | £2,000 – £3,500 / m² | Including preliminaries, structure, services, and fit-out. Site cost extra. |
All prices are indicative only and based on 2025 London market rates. Contact us for a free, fixed-price quotation for your specific project.
What's Included in Our Quotes?
Fully Detailed Specification
Every item priced line-by-line. No lump-sums that hide unknowns.
Fixed Price
We hold our price. The only additions are client-instructed variations.
5-Year Warranty
All our work is warranted for 5 years and backed by Lloyd's insurance.
Get Your Fixed-Price Quote
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