Cornwall
Rear extension plans and planning applications in Cornwall
Measured survey, design options, planning drawings and the application, handled for you. Rear extensions in Cornwall: we cover 10 towns including Redruth, Falmouth and St Austell, with design, approvals and the build under one contract.
Planning applications in Redruth go to the local planning authority, and we check its local design guidance for rear extensions before drawing. Stone-built and rendered houses are common around Cornwall, so matching the walling is a design decision in its own right: natural stone, reconstituted stone or a render finish across old and new.
What does it cost in Cornwall?
As a guide, £1,000–£2,500 including VAT. These are guide ranges; the written quote after the survey is the figure that counts.
Do you need planning permission in Cornwall?
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.
A householder planning application in England costs £548 (£575 for applications made from 8 December 2026), and a lawful development certificate for proposed work costs half the householder fee.
Councils aim to decide householder applications within 8 weeks of validation, and prior approval within 42 days.
Where in Cornwall do we work?
FAQ
Questions people ask
Do I need an architect?
You need accurate drawings by someone who knows householder planning; we provide them.
Can I see the design in 3D?
Yes; we produce simple 3D views so you can judge the size and light.
What if planning is refused?
We review the reasons with you, amend and resubmit (often free of a second fee within 12 months in England) or appeal.
Do you cover all of Cornwall?
We cover 10 towns and districts in Cornwall, including Redruth, Falmouth and St Austell.
Who builds the extension?
Vetted building teams working under contract to us; your contract is with S&K Property Investments and Improvement Ltd.