Extensions in Calne: design, planning and build
We design and build house extensions for homes in Calne and the surrounding Wiltshire area, with guide prices adjusted for the region.
- Postcode districtsSN11
- Price regionSouth West England (×1.02)
- Planning rulesEngland
- Site visitFree, no obligation
Areas we cover around Calne
Across SN11, we can visit, measure and advise. We also work in nearby Chippenham (6 miles), Devizes (7 miles), Melksham (8 miles), Trowbridge (12 miles), Swindon (12 miles). For homes towards Somerset, Bath is around 16 miles away.
What extensions cost in Calne
We publish guide prices so you can budget before anyone visits. For Calne they are adjusted by ×1.02, the factor we use across South West England.
| Extension type | Example size | Standard spec (inc VAT) |
|---|---|---|
| Side return extensions | 11 m² | £26,500 – £34,000 |
| Kitchen extensions | 20 m² | £42,500 – £54,500 |
| Single-storey rear extensions | 20 m² | £41,500 – £53,500 |
| Extensions over a garage | 12 m² | £25,500 – £33,500 |
| Conservatory replacement extensions | 14 m² | £30,500 – £39,500 |
| Orangery extensions | 16 m² | £45,500 – £57,500 |
| Wraparound extensions | 25 m² | £58,500 – £74,000 |
Do extensions in Calne need planning permission?
In England a single-storey rear extension can usually go up to 3 m beyond the original rear wall of a semi-detached or terraced house, or 4 m on a detached house, without a planning application, provided it is no more than 4 m high, keeps eaves to 3 m within 2 m of a boundary and, with other buildings, covers no more than half the land around the original house. The larger home extension prior approval scheme raises those depths to 6 m and 8 m, with neighbours notified and a 42-day decision.
In England a single-storey side return infill is often permitted development if it stays within the height limits and is no wider than half the width of the original house. Conservation areas, listed buildings and flats always need an application, and the boundary wall usually brings in the Party Wall Act.
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).
Which extension suits a Calne home?
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.
Depending on the plot, annexe extensions and orangery extensions are often the strongest options, with pitched roof extensions worth considering where there is room.
Choose an extension type
- Annexe extensions · from £56,000
- Kitchen extensions · from £27,500
- Bedroom extensions · from £26,500
- Single-storey rear extensions · from £21,000
- Pitched roof extensions · from £22,500
- Wraparound extensions · from £36,500
- Side extensions · from £22,000
- Extension plans and drawings · from £1,200
- Bungalow extensions · from £26,500
- Conservatory replacement extensions · from £20,000
- Orangery extensions · from £30,500
- Timber frame extensions · from £21,000
- Flat roof extensions · from £21,000
- Planning permission for extensions · from £350
- Building regulations for extensions · from £900
- Porch extensions · from £4,050
- Extensions over a garage · from £24,000
- Double-storey extensions · from £38,500
- Home office extensions · from £16,000
- Utility and boot room extensions · from £14,000
- Glass box extensions · from £30,500
- Side return extensions · from £18,000
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
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
The price is fixed in writing once the design is settled, with a clear programme and payment stages.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Questions about extensions in Calne
How much does an extension cost in Calne?
Using our South West England factor (×1.02), a standard-spec single-storey extension of 20 m² is a guide £41,500 to £53,500 including VAT, and a 32 m² two-storey extension £58,500 to £77,000. Your written price follows the survey.
Will my neighbours need to be told?
If you apply for planning or prior approval the council notifies them, and in England party wall notices may be needed for work near a shared boundary.
Can I get a price before anyone visits?
Yes. This page shows guide prices adjusted for Calne, and the guide-price tool gives a range for your own size and finish in about a minute.
Do you cover all of Calne?
Yes, including the surrounding parts of Wiltshire. Site visits are free and there is no obligation.
Book a free site visit in Calne
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.