Devizes bedroom extensions, designed and built
A bedroom extension in Devizes starts with the right design and the right approval route. We take care of both, then build it with our own project management.
- Guide price in DevizesFrom £26,500 inc VAT
- PlanningUsually a householder application
- Build time14–22 weeks on site
- Postcode districtsSN10
Bedroom extension prices in Devizes
These guide figures apply our South West England adjustment (×1.02) to national rates. They include VAT at 20% and cover the build itself; design and council fees are listed separately.
Typical rates in Devizes: £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 |
Want a range for your exact size? The guide-price tool takes about a minute.
Working in Devizes
We cover Devizes and the postcode districts SN10. Neighbouring towns we cover include Melksham (7 miles), Calne (7 miles), Trowbridge (10 miles), Chippenham (10 miles).
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.
Planning rules that apply in Devizes
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.
In a conservation area, national park, National Landscape, the Broads or a World Heritage Site the permitted development limits are tighter (no side or two-storey extensions without an application). Listed homes need listed building consent, and if permitted development rights have been removed, any extension needs an application.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
Applications are decided by the local planning authority (your district, borough or unitary council).
What is included
- Planning drawings and application
- Heating extended to the new rooms
- Fire safety: escape windows and smoke alarms to building regulations
- Structure, roof, insulation and finish
- En-suite drainage and ventilation design
- Layout options: two-storey, over-garage or ground floor
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
We visit your Devizes home, measure up, talk through what you want and check the planning position.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Bedroom extension questions answered
How long does a bedroom extension take to build in Devizes?
On site, typically 14 to 22 weeks once approvals are in place. Before that, allow 8–14 weeks design and approvals.
Do I need building regulations approval in Devizes?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Who do I contract with for a bedroom extension in Devizes?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
Does an en-suite need a window?
No, but it needs mechanical extraction that meets the building regulations. We design the duct route at the drawing stage.
How much does a bedroom extension cost?
Our guide range is about £1,630 to £3,260 per m² including VAT. A bedroom with an en-suite of about 18 m² is typically £34,500 to £45,000 at standard spec, depending on whether it is part of a larger two-storey build.
Book a free site visit in Devizes
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.