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Devon

Building Regulations for rear extensions in Devon

Construction drawings, structural calculations and building control through to the completion certificate. We design and build rear extensions across Devon, from Plymouth and Exeter to Paignton, covering single-storey kitchen extensions, two-storey additions, side returns and wraparounds.

Building control inspector with a clipboard checking new blockwork walls of a rear extension under construction

Stone-built and rendered houses are common around Devon, 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 Devon?

As a guide, £2,500–£5,500 including VAT. These are guide ranges; the written quote after the survey is the figure that counts.

What approvals does it need in Devon?

Planning and Building Regulations are separate in England: even a permitted development extension is inspected for foundations, drainage, structure, insulation, fire safety and ventilation, through the council or a registered building control approver, ending with a completion certificate.

New fabric must meet Approved Document L (2021 edition incorporating 2023 amendments): walls 0.18, roof 0.15 and floor 0.18 W/m²K, windows 1.4 W/m²K or Band B. Under the simple route, new windows, doors and rooflights should not exceed 25% of the extension floor area plus any openings removed; more glass is possible with a whole-house calculation.

Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent.

Where in Devon do we work?

FAQ

Questions people ask

Full plans or building notice?

Full plans for most extensions: the design is checked before work starts. A building notice suits only simple jobs.

Who inspects the work?

The council's building control team or a registered building control approver (in Scotland, the council's building standards team).

What is a completion certificate?

The document confirming the work meets the regulations. Keep it; buyers' solicitors ask for it.

Do you cover all of Devon?

We cover 21 towns and districts in Devon, including Plymouth, Exeter and Paignton.

Who builds the extension?

Vetted building teams working under contract to us; your contract is with S&K Property Investments and Improvement Ltd.

Next step

See what your rear extension would cost

Get a guide price online in a couple of minutes, or book a free site visit and we'll measure up and talk you through the planning route.

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