Double-storey extensions for homes in Chippenham
From the first sketch to final sign-off, we plan and build double-storey extensions in Chippenham and the surrounding Wiltshire area.
- Guide price in ChippenhamFrom £38,500 inc VAT
- PlanningUsually a householder application
- Build time16–24 weeks on site
- Postcode districtsSN15
Planning rules that apply in Chippenham
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.
Applications are decided by the local planning authority (your district, borough or unitary council).
Working in Chippenham
We cover Chippenham and the postcode districts SN15. The same team covers Calne (6 miles), Melksham (6 miles), Trowbridge (10 miles), Devizes (10 miles), all within easy reach.
For homes towards Somerset, Bath is around 12 miles away. In the South West, local stone, render and brick vary from town to town, so matching materials is a big part of designing an extension that looks right.
When a double-storey extension makes sense
- Growing families who need a bedroom as well as a bigger kitchen
- Houses with enough distance to the rear or side boundary
- Homeowners who would otherwise consider moving
What should I budget for a double-storey extension in Chippenham?
Labour and material costs vary across the UK, so for Chippenham we use our South West England factor (×1.02). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Chippenham: £1,580 to £3,060 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m, two floors 24 m² | £38,500 – £46,500 | £44,000 – £58,000 | £56,000 – £73,500 |
| 4 m × 4 m, two floors 32 m² | £50,500 – £60,500 | £58,500 – £77,000 | £75,000 – £98,000 |
| 4 m × 6 m, two floors 48 m² | £75,500 – £91,000 | £88,000 – £115,500 | £112,500 – £147,000 |
For a figure based on your own dimensions, use our guide-price tool.
What happens next
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
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
Design and approvals
Once the layout is agreed, we deal with the council: planning permission or written confirmation that none is needed, plus building control.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Double-storey extension questions answered
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Chippenham, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
How long does a double-storey extension take to build in Chippenham?
On site, typically 16 to 24 weeks once approvals are in place. Before that, allow 8–16 weeks design and approvals.
Who do I contract with for a double-storey extension in Chippenham?
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 a double-storey extension need planning permission?
Often, yes. In England a two-storey rear extension can be permitted development only if it projects no more than 3 m and sits at least 7 m from the rear boundary, with matching roof pitch and obscure side windows. Side extensions over one storey always need planning permission. We confirm the route at the survey.
Do I need a Party Wall Agreement?
If you are in England or Wales and the work involves a shared wall or digging foundations close to a neighbour, the Party Wall etc. Act 1996 applies and notices must be served before work starts. We tell you which notices are needed.
Book a free site visit in Chippenham
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.