Bedroom extensions in Devon
If you live in Devon and want more space without moving, a bedroom extension is one of the most practical ways to get it. We handle the drawings, approvals and the build.
- Guide priceFrom £26,500 inc VAT
- PlanningUsually a householder application
- Towns covered9
- Site visitFree, no obligation
What is included
- Layout options: two-storey, over-garage or ground floor
- En-suite drainage and ventilation design
- Structure, roof, insulation and finish
- Fire safety: escape windows and smoke alarms to building regulations
New bedrooms on an upper floor need an escape window or a protected route to the outside under the building regulations. We design the window sizes and stair route to meet that from the outset.
How much does a bedroom extension cost in Devon?
Labour and material costs vary across the UK, so for Devon we use our South West England factor (×1.02). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Devon: £1,630 to £3,260 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| One bedroom 12 m² | £26,500 – £32,500 | £26,500 – £34,500 | £29,000 – £39,500 |
| Bedroom and en-suite 18 m² | £29,000 – £36,000 | £34,500 – £45,000 | £44,000 – £59,000 |
| Two rooms 30 m² | £48,500 – £60,000 | £58,000 – £75,000 | £73,000 – £98,000 |
Try the guide-price tool to see a range for your own size and finish.
Do I need planning permission in Devon?
In England a two-storey rear extension is permitted development only if it projects no more than 3 m from the original rear wall, sits at least 7 m from the rear boundary, matches the roof pitch and uses obscure, non-opening side windows upstairs. Most two-storey extensions therefore go through a householder planning application, which costs £548 from 1 April 2026 and normally takes about 8 weeks.
Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
Applications are decided by the local planning authority (your district, borough or unitary council).
Covering Devon
Towns we cover in Devon include Plymouth, Exeter, Paignton, Torquay, Newton Abbot, Exmouth, Barnstaple, Bideford. South West homes range from terraced streets in the cities to stone cottages and bungalows in the countryside, and conservation areas are common in historic centres.
How the project works
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
First, a site visit: we look at the house, garden, access and drains and listen to what you need.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Bedroom extension questions answered
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Devon, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Do I need building regulations approval in Devon?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Do you cover all of Devon?
Yes, across the whole of Devon. Site visits are free and there is no obligation.
Will a new bedroom need planning permission?
Upstairs additions usually do. Ground-floor rooms may fall within permitted development, depending on size and position.
Can I add a ground-floor bedroom for a relative?
Yes. A ground-floor bedroom with an accessible shower room is a common request. If it will be lived in as a self-contained home, planning treats it differently, so tell us how it will be used.
Book a free site visit in Devon
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.