Home office extensions across Calne
If you live in Calne and want more space without moving, a home office extension is one of the most practical ways to get it. We handle the drawings, approvals and the build.
- Guide price in CalneFrom £16,000 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Build time8–12 weeks on site
- Postcode districtsSN11

When a home office extension makes sense
- People who work from home most of the week
- Homes where a loft or garden room is not practical
- Households that need a second quiet room
Planning rules that apply in Calne
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.
Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.
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.
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).
Covering Calne
Site visits are available across Calne (SN11). Nearby, we also take on projects in Chippenham (6 miles), Devizes (7 miles), Melksham (8 miles), Trowbridge (12 miles).
Just over the Somerset border, Bath is about 16 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.
Home office extension prices in Calne
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 Calne: £1,890 to £3,470 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2.5 m × 3.2 m 8 m² | £16,000 – £19,500 | £17,500 – £22,500 | £22,000 – £28,000 |
| 3 m × 3.6 m 11 m² | £20,500 – £25,000 | £24,000 – £30,500 | £30,000 – £38,500 |
| 3 m × 5 m 15 m² | £28,000 – £34,000 | £32,500 – £41,500 | £41,000 – £52,500 |
Want a range for your exact size? The guide-price tool takes about a minute.
Our process, step by step
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
We produce the drawings and structural design, and manage the approvals so they are in place before work starts.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Your questions about a home office extension in Calne
Do I need building regulations approval in Calne?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
How long does a home office extension take to build in Calne?
On site, typically 8 to 12 weeks once approvals are in place. Before that, allow 4–10 weeks design and approvals.
Will my neighbours in Calne be involved?
If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
How much does a home office extension cost?
Our guide range is about £1,890 to £3,470 per m² including VAT. An 11 m² standard-spec office is typically £24,000 to £30,500 in Calne.
Can I claim the cost against tax?
Building work on your home is not normally an allowable business expense, and claiming it can have capital gains tax effects. Speak to an accountant before assuming any tax relief.
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.