Compare House Extension Quotes — 3 Free, No-Obligation Quotes
A house extension in the UK typically costs £1,800–£3,000 per m² — around £36,000–£60,000 for a 20m² single-storey rear extension, before finishes. Tell us about your job and we’ll match you with up to 3 vetted, insured extension builders near you — compare house extension quotes side by side and pick the best value. 100% free, no obligation, and most quotes come back within 24 hours.
How to get the best house extension quotes
- Get three quotes from builders who've done similar extensions locally — ask to see them.
- Make sure the quote separates build cost from finishes, fees and VAT so you can compare fairly.
- Agree a payment schedule tied to stages, never a large up-front lump sum.
What to check before you book
Always get the quote in writing with a clear scope, and confirm the builders is insured and offers a workmanship guarantee. Read recent customer reviews, check the quotes cover the same specification, and never pay a large deposit up front — tie payments to completed stages.
Typical house extension cost
A house extension in the UK typically costs £1,800–£3,000 per m² — around £36,000–£60,000 for a 20m² single-storey rear extension, before finishes.
| Option | Typical UK price (2026) |
|---|---|
| Single-storey (per m²) | £1,800–£2,600 |
| Double-storey (per m²) | £1,500–£2,200 |
| 20m² single-storey | £36,000–£52,000 |
| Kitchen extension (typical) | £40,000–£70,000 |
Prices vary by spec, region and access. For the full breakdown see our house extension cost guide or try the house extension cost calculator.
House Extension quotes — FAQs
How much does a house extension cost in the UK?
Typically £1,800–£3,000 per m² — about £36,000–£60,000 for a 20m² single-storey rear extension before finishes. See the extension cost guide or use the calculator.
How many extension quotes should I get?
Three detailed, written quotes for the same drawings and spec, so you compare like for like. Every quote is free and no-obligation.
Do I need planning permission for an extension?
Many single-storey extensions fall under permitted development, but limits apply. Your builder or architect can confirm — and we can match you with both.
Ready to start? Get your 3 free house extension quotes → Or explore house extension services and find trusted extension builders near you.