East Sussex
Rear extensions for detached houses in East Sussex
Wider, deeper rear extensions with room for vaulted roofs and big glazing. Across East Sussex we handle the whole rear extension: survey, drawings, the planning route, building control and the build. Towns we cover here include Brighton, Eastbourne and Hastings.
Detached houses in East Sussex often have room for a deeper rear extension under England's prior approval route or a full-width design. Commuter semis and detached houses make up much of East Sussex, and longer gardens make England's prior approval route for deeper rear extensions worth considering.
How much does a detached house rear extension cost in East Sussex?
A detached house rear extension in East Sussex is priced at £2,180–£3,580 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 |
|---|---|
| 4 m wide × 6 m deep (24 m²) | £52,500–£86,000 |
| 5 m wide × 8 m deep (40 m²) | £87,500–£143,500 |
We put a fixed price in writing once the design is agreed, and explain any provisional sums such as foundations.
Do you need planning permission in East Sussex?
Under England's householder permitted development rules you can usually add 3 metres at the back of an attached house, or 4 metres on a detached house, without a planning application, as long as the extension stays under 4 metres high and its eaves stay under 3 metres where it is within 2 metres of a boundary.
If 3 or 4 metres is not enough, England's prior approval route allows 6 metres on a terraced or semi-detached house and 8 metres on a detached house for a single-storey rear extension. Neighbours are consulted, the council decides within 42 days, and the fee is £249, rising to £310 from 8 December 2026.
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 East Sussex 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 East Sussex?
We cover 15 towns and districts in East Sussex, including Brighton, Eastbourne and Hastings.
Who builds the extension?
Vetted building teams working under contract to us; your contract is with S&K Property Investments and Improvement Ltd.