Dorset
Permitted development rear extensions in Dorset
Designing to the no-application limits, with a lawful development certificate as proof. Rear extensions in Dorset: we cover 14 towns including Bournemouth, Poole and Weymouth, with design, approvals and the build under one contract.

Dorset has Victorian terraces nearer the centre and post-war semis on the edges. Sloping gardens are frequent, which affects floor levels and steps down to the patio.
How much does a permitted development rear extension cost in Dorset?
A permitted development rear extension in Dorset is priced at £1,980–£3,220 per square metre including VAT as a guide, before kitchen fit-out and fees. South West prices run slightly above our West Midlands baseline; natural stone to match the house is the main variable.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £23,500–£38,500 |
| 4 m wide × 5 m deep (20 m²) | £39,500–£64,500 |
| 4 m wide × 6 m deep (24 m²) | £47,500–£77,500 |
These are guide ranges; the written quote after the survey is the figure that counts.
Do you need planning permission in Dorset?
English permitted development (Class A) allows a single-storey rear extension of 3 metres on a terraced or semi-detached house and 4 metres on a detached one, measured from the original house, with a maximum height of 4 metres and eaves of no more than 3 metres within 2 metres of a boundary.
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 Dorset do we work?
FAQ
Questions people ask
Is permitted development the same as planning permission?
No; it is a national grant of permission for work within set limits, so no application is needed.
Do I still need Building Regulations?
Yes, always.
Can my neighbours object?
Not to permitted development itself, though they can ask the council to check it complies. Prior approval does involve neighbour consultation.
Do you cover all of Dorset?
We cover 14 towns and districts in Dorset, including Bournemouth, Poole and Weymouth.
Who builds the extension?
Vetted building teams working under contract to us; your contract is with S&K Property Investments and Improvement Ltd.