Plan Then Build

Garden room / outbuilding cost in East of England

East of England build costs run at 108% of the UK national average, across councils including Cambridge, Norwich, Ipswich. A 20m² example at mid-range spec: £80,307–£108,650. Adjust the size and spec below for your project.

Permitted Development & Cost Checker

England only. Takes about a minute.

Garden room / outbuilding cost by size and spec in East of England

SizeBasicMid-rangePremium
15£41,826–£56,589£60,230–£81,488£86,255–£116,698
20£55,769–£75,452£80,307–£108,650£115,007–£155,598
30£83,653–£113,177£120,460–£162,975£172,511–£233,397

Does a garden room / outbuilding need planning permission?

Council planning fees in East of England

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

Garden room / outbuilding cost in other regions

Cost bands refreshed quarterly from published 2026 UK cost guides.