Derbyshire
Rear extensions for detached houses in Derbyshire
Wider, deeper rear extensions with room for vaulted roofs and big glazing. We design and build rear extensions across Derbyshire, from Derby and Chesterfield to High Peak, covering single-storey kitchen extensions, two-storey additions, side returns and wraparounds.
Detached houses in Derbyshire often have room for a deeper rear extension under England's prior approval route or a full-width design. Derbyshire has plenty of inter-war semis and bungalows, and single-storey rear extensions suit both.
How much does a detached house rear extension cost in Derbyshire?
For Derbyshire we work from the East Midlands rate: £1,890–£3,100 per square metre of new floor, including VAT, standard specification. East Midlands prices sit a little below our West Midlands baseline.
| Size | Guide price inc VAT |
|---|---|
| 4 m wide × 6 m deep (24 m²) | £45,500–£74,500 |
| 5 m wide × 8 m deep (40 m²) | £75,500–£124,000 |
Your written price follows a measured survey and an agreed design, so it reflects your house, not an average.
Do you need planning permission in Derbyshire?
In England a single-storey rear extension can often be built under permitted development: up to 3 metres beyond the original rear wall of an attached house, or 4 metres on a detached house, no higher than 4 metres, with eaves no higher than 3 metres if any part is within 2 metres of a boundary.
England also has the larger home extension route: a single-storey rear extension of up to 6 metres on an attached house or 8 metres on a detached house, after prior approval from the council. The council notifies your neighbours and has 42 days to decide; the fee is £249 (£310 for applications made from 8 December 2026). The route is not available on designated land such as conservation areas.
A two-storey rear extension can be permitted development in England only if it projects no more than 3 metres, stays at least 7 metres from the rear boundary, matches the existing roof pitch and has obscure-glazed upper side windows. In practice most double-storey rear extensions go through a householder planning application.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent.
Where in Derbyshire do we work?
FAQ
Questions people ask
How deep can I extend a detached house?
4 metres under permitted development in England, or 8 metres with prior approval, outside designated land.
Can I have a vaulted ceiling?
Yes, with a pitched roof and exposed or boxed rafters, subject to the height limits.
Is an oak frame worth it?
It is a premium finish with a long life; it costs more than blockwork with a plain roof.
Do you cover all of Derbyshire?
We cover 22 towns and districts in Derbyshire, including Derby, Chesterfield and High Peak.
Who builds the extension?
Vetted building teams working under contract to us; your contract is with S&K Property Investments and Improvement Ltd.