Extensions over a garage across Chippenham
We design and build over-garage extensions for houses in Chippenham, with a written price once the survey and design are done and one point of contact throughout.
- Guide price in ChippenhamFrom £24,000 inc VAT
- PlanningHouseholder application needed
- Build time12–18 weeks on site
- Postcode districtsSN15
Local to Chippenham
Our survey diary covers Chippenham, including SN15. The same team covers Calne (6 miles), Melksham (6 miles), Trowbridge (10 miles), Devizes (10 miles), all within easy reach.
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.
What we take care of
- New floor structure, walls and roof
- Opening into the existing first floor
- Insulation, electrics, heating and finish
- Strengthening or rebuilding the garage walls if needed
- Design and householder planning application
Planning rules that apply in Chippenham
In England any side extension over one storey, including a room built over a side garage, needs a householder planning application. The fee is £548 from 1 April 2026 and councils aim to decide within 8 weeks.
The planning position for a specific Chippenham address depends on its history and any designations, which is why we check it at the first visit.
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.
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).
Over-garage extension prices in Chippenham
Prices below are for Chippenham, using the South West England factor of ×1.02. They are guide ranges including VAT for the build only, not a quote.
Typical rates in Chippenham: £1,840 to £3,470 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| Over a single garage 12 m² | £24,000 – £30,000 | £25,500 – £33,500 | £33,000 – £42,000 |
| Over a large single garage 16 m² | £29,000 – £36,000 | £34,000 – £44,500 | £44,000 – £55,500 |
| Over a double garage 24 m² | £44,000 – £54,000 | £51,000 – £66,500 | £66,000 – £83,500 |
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
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Your questions about an over-garage extension in Chippenham
Do you cover all of Chippenham?
Yes. We cover Chippenham and the surrounding parts of Wiltshire. Site visits are free and there is no obligation.
Do I need building regulations approval in Chippenham?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
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.
Can I keep using the garage during the build?
Usually not for parking. The garage roof is removed and the space below is used for access and props for part of the build.
How much does a room over a garage cost?
Our guide range is about £1,840 to £3,470 per m² including VAT. A single-garage room of about 12 m² usually costs £25,500 to £33,500 at standard spec, more if the garage needs rebuilding.
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.