UK build cost index, 2026-Q4
What building work costs in every UK region
Quick answerA 20m² single storey rear extension costs from £47,500 to £56,500 in Northern Ireland to £71,000 to £88,500 in Inner London, including VAT and professional fees. The West Midlands, where our job data comes from, sits at £54,000 to £62,000.
Regional prices at a glance
Standard spec, typical sizes, VAT and fees included. The index compares each region with our West Midlands base of 1.00.
| Region | Single storey, 20m² | Kitchen extension, 24m² | Dormer loft | Garage conversion | Index |
|---|---|---|---|---|---|
| Inner London | £71,000 to £88,500 | £93,000 to £115,500 | £63,500 to £81,000 | £26,000 to £32,500 | 1.38 |
| Outer London | £64,000 to £79,500 | £84,000 to £104,500 | £57,500 to £72,500 | £23,500 to £29,500 | 1.24 |
| South East | £59,500 to £71,000 | £78,500 to £94,000 | £53,500 to £65,000 | £22,000 to £26,000 | 1.13 |
| East of England | £57,000 to £68,000 | £75,500 to £90,000 | £51,000 to £62,500 | £21,000 to £25,000 | 1.08 |
| South West | £55,500 to £66,000 | £73,500 to £88,000 | £49,500 to £60,500 | £20,500 to £24,500 | 1.05 |
| West Midlands | £54,000 to £62,000 | £71,500 to £82,500 | £48,500 to £56,500 | £20,000 to £23,000 | 1.00 |
| Scotland | £52,500 to £63,000 | £70,000 to £83,500 | £47,500 to £57,500 | £19,500 to £23,000 | 1.00 |
| East Midlands | £52,000 to £62,500 | £69,500 to £83,000 | £47,000 to £57,000 | £19,000 to £23,000 | 0.99 |
| North West | £52,000 to £62,500 | £69,500 to £83,000 | £47,000 to £57,000 | £19,000 to £23,000 | 0.99 |
| Yorkshire and the Humber | £50,500 to £60,500 | £67,500 to £81,000 | £45,500 to £55,500 | £18,500 to £22,500 | 0.96 |
| Wales | £50,500 to £60,500 | £67,500 to £81,000 | £45,500 to £55,500 | £18,500 to £22,500 | 0.96 |
| North East | £49,500 to £59,500 | £66,500 to £79,500 | £44,500 to £54,500 | £18,250 to £21,750 | 0.94 |
| Northern Ireland | £47,500 to £56,500 | £63,500 to £76,000 | £42,500 to £52,000 | £17,500 to £21,000 | 0.90 |
Regional cost guides
- RegionLondonExtension costs in London (2026): real prices by postcode£71,000 to £88,500
- Regionthe South EastExtension costs in the South East (2026): local prices by area£59,500 to £71,000
- Regionthe East of EnglandExtension costs in the East of England (2026): prices by area£57,000 to £68,000
- Regionthe South WestExtension costs in the South West (2026): prices by area£55,500 to £66,000
- Regionthe East MidlandsExtension costs in the East Midlands (2026): prices by area£52,000 to £62,500
- Regionthe West MidlandsExtension costs in the West Midlands (2026): real local prices£54,000 to £62,000
- Regionthe North WestExtension costs in the North West (2026): prices by area£52,000 to £62,500
- RegionYorkshire and the HumberExtension costs in Yorkshire (2026): prices by area£50,500 to £60,500
- Regionthe North EastExtension costs in the North East (2026): prices by area£49,500 to £59,500
- RegionWalesExtension costs in Wales (2026): prices by area£50,500 to £60,500
- RegionScotlandExtension costs in Scotland (2026): prices by area£52,500 to £63,000
- RegionNorthern IrelandExtension costs in Northern Ireland (2026): local prices£47,500 to £56,500
West Midlands towns
Our home patch, priced district by district from completed local jobs.
- DY1Extension cost in Dudley£53,000 to £60,500
- WV3Extension cost in Wolverhampton£53,500 to £61,500
- B14Extension cost in Birmingham£54,500 to £62,500
- WS5Extension cost in Walsall£53,500 to £61,500
- DY8Extension cost in Stourbridge£55,000 to £63,000
- B91Extension cost in Solihull£57,000 to £65,500
- B73Extension cost in Sutton Coldfield£56,000 to £64,500
- CV3Extension cost in Coventry£53,500 to £63,500
- WR1Extension cost in Worcester£55,000 to £63,000
- DY10Extension cost in Kidderminster£53,500 to £61,500
- TF3Extension cost in Telford£50,000 to £57,500
- SY3Extension cost in Shrewsbury£54,500 to £62,500
- WV16Extension cost in Bridgnorth£54,500 to £62,500
Using these figures
You’re welcome to quote these figures with a link to this page. They are refreshed each quarter; this edition is 2026-Q4. For how the index is built, read how we price.