Extension Cost per m² UK 2026

UK extension costs are usually quoted per m². This guide tables typical 2026 per-m² rates by extension type, spec level, and region — so you can sanity-check any builder's quote.

Quick answer

Typical UK price range: £1,800–£4,500. Typical time: Varies.

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Extension type Single-storey rear Double-storey Side return Wrap-around Kitchen extension Oak frame

Extension floor area (m²)

Region London South East South West Midlands North of England Scotland Wales Northern Ireland

Specification level Basic / standard Mid-range Premium / high-end

Extras

Bi-fold doors £2,500–£6,000 Roof lanterns £1,500–£3,500 Underfloor heating £2,500–£5,000 New kitchen fit £8,000–£25,000 Architect & plans £2,500–£5,000

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Estimate only. Prices reflect 2026 UK market data — get quotes from local tradespeople for accurate pricing.

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Budget Under £5,000 £5,000 – £15,000 £15,000 – £30,000 £30,000 – £60,000 £60,000+ Not sure

Timeline As soon as possible 1 – 3 months 3 – 6 months 6+ months Just researching

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Key points

• Single storey: £2,000–£2,800/m² basic; £2,400–£3,500/m² mid; £3,500–£5,000/m² premium
• Double storey: 60–80 % more than single but lower per m² (£1,800–£2,600)
• Side return: £2,200–£3,000/m²
• Oak frame: £2,800–£4,000/m²

Cost breakdown

Item	Low	High
Single-storey basic	£2,000	£2,800
Single-storey mid-range	£2,400	£3,500
Single-storey premium	£3,500	£5,000
Double-storey	£1,800	£2,600
Side return	£2,200	£3,000
Wrap-around	£2,400	£3,200
Oak frame	£2,800	£4,000

Cost by UK region

Region	Typical cost
London	£4,252
South East	£3,937
South West	£3,465
Midlands	£3,150
North England	£2,835
Scotland	£2,992
Wales	£2,835

How to save money

• Always benchmark against the same spec — '£/m²' from different builders may include very different things
• Architect drawings + planning are typically separate from the per-m² rate
• London adds 25–35 %; the North subtracts 10 %

How to find a trusted tradesperson

Get at least 3 quotes from vetted UK trade networks:

• Checkatrade
• MyBuilder
• Bark

FAQs

Why is per-m² lower for double-storey?

You share the foundations and roof across two floors — so the per-m² cost falls even though the total is higher.

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Disclaimer: Prices are guide ranges based on 2026 UK market data. Get quotes from local tradespeople for accurate pricing.