Plan Then Build

Side extension cost in East Midlands

East Midlands build costs run at 95% of the UK national average, across councils including Nottingham, Leicester, Derby. A 20m² example at mid-range spec: £70,640–£95,572. Adjust the size and spec below for your project.

Permitted Development & Cost Checker

England only. Takes about a minute.

Side extension cost by size and spec in East Midlands

SizeBasicMid-rangePremium
15£36,792–£49,777£52,980–£71,679£75,873–£102,651
20£49,056–£66,369£70,640–£95,572£101,164–£136,868
30£73,583–£99,554£105,960–£143,358£151,745–£205,303

Does a side extension need planning permission?

Council planning fees in East Midlands

Each council sets its own fees and decision times. See your council’s page for the exact figures.

Side extension cost in other regions

Cost bands refreshed quarterly from published 2026 UK cost guides.