Buckinghamshire
Two-storey rear extensions in Buckinghamshire
A larger kitchen downstairs and an extra bedroom or bathroom upstairs, under one roof. Across Buckinghamshire we handle the whole rear extension: survey, drawings, the planning route, building control and the build. Towns we cover here include Milton Keynes, High Wycombe and Aylesbury.

In Buckinghamshire we check the neighbours' rear windows first, because the upper floor is where most two-storey schemes win or lose planning. Around Buckinghamshire the housing ranges from inter-war semis to 1960s and 1970s estates with good-sized gardens. Many of the newer estates had permitted development rights removed by condition, so we check the planning history before anything is drawn.
How much does a two-storey rear extension cost in Buckinghamshire?
A two-storey rear extension in Buckinghamshire is priced at £2,020–£3,020 per square metre including VAT as a guide, before kitchen fit-out and fees. South East prices run above our West Midlands baseline, mainly on labour rates and clay-soil foundations.
| Size | Guide price inc VAT |
|---|---|
| 3 m × 5 m footprint, two floors (30 m²) | £60,500–£90,500 |
| 4 m × 6 m footprint, two floors (48 m²) | £97,000–£145,000 |
These are guide ranges; the written quote after the survey is the figure that counts.
Do you need planning permission in Buckinghamshire?
England's rules allow a rear extension of more than one storey without an application only when it is no deeper than 3 metres and at least 7 metres from the boundary opposite the rear wall, and never on designated land. Most two-storey schemes need householder planning permission.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent.
Where in Buckinghamshire do we work?
FAQ
Questions people ask
Does a two-storey rear extension need planning permission?
Almost always. England and Northern Ireland allow 3 metres without an application only if at least 7 metres remains to the rear boundary; Wales and Scotland are similar or stricter.
Is two-storey cheaper per square metre than single-storey?
Usually yes, because the foundations and roof are shared across twice the floor area. The total cost is higher.
Can I add an en-suite upstairs?
Yes. We plan the soil pipe route early so the bathroom sits where drainage works without boxing through the room below.
Do you cover all of Buckinghamshire?
We cover 13 towns and districts in Buckinghamshire, including Milton Keynes, High Wycombe and Aylesbury.
Who builds the extension?
Vetted building teams working under contract to us; your contract is with S&K Property Investments and Improvement Ltd.