Glass box extensions across Wiltshire
Wiltshire homeowners can use us for the whole glass extension project: survey, design, planning or permitted development checks, building regulations and the build itself.
- Guide priceFrom £30,500 inc VAT
- PlanningSame limits as single-storey rear; glazing checked for building regs
- Towns covered8
- Site visitFree, no obligation
Towns in Wiltshire
When a glass extension makes sense
- Period and listed-style houses where a light touch is wanted
- Small infill spaces and side returns
- Garden-facing dining rooms
Solar gain is the risk. We specify solar-control glass, plan for opening vents or sliding panels, and avoid fully glazed roofs on south-facing extensions unless shading is included.
Do I need planning permission in Wiltshire?
In England a glazed or orangery-style extension follows the same size limits as any single-storey rear extension: 3 m or 4 m without an application, or up to 6 m and 8 m through prior approval. Building regulations limit glazing to about a quarter of the new floor area plus the openings it replaces, unless whole-house calculations show the design still performs.
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.
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.
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).
Glass extension prices in Wiltshire
Labour and material costs vary across the UK, so for Wiltshire we use our South West England factor (×1.02). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Wiltshire: £3,060 to £5,920 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2 m × 4 m 8 m² | £30,500 – £37,000 | £30,500 – £38,500 | £35,000 – £47,500 |
| 3 m × 4 m 12 m² | £36,500 – £44,500 | £42,500 – £54,000 | £52,500 – £71,000 |
| 3 m × 6 m 18 m² | £55,000 – £66,500 | £64,000 – £81,000 | £78,500 – £106,500 |
For a figure based on your own dimensions, use our guide-price tool.
Local to Wiltshire
Towns we cover in Wiltshire include Swindon, Salisbury, Trowbridge, Chippenham, Melksham, Devizes, Warminster, Calne. 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.
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
We produce the drawings and structural design, and manage the approvals so they are in place before work starts.
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
The build is managed from start to finish, inspected at each stage and signed off on completion.
Glass extension questions answered
Do you cover all of Wiltshire?
Yes, across the whole of Wiltshire. Site visits are free and there is no obligation.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Wiltshire, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Will my neighbours in Wiltshire 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 glass extension cost?
Our guide range is about £3,060 to £5,920 per m² including VAT, because structural glass is made to order. A 12 m² standard-spec glass extension is typically £42,500 to £54,000 in Wiltshire.
Are glass extensions cold in winter?
Modern double or triple glazing with warm-edge spacers and underfloor heating keeps them comfortable. They are not as warm as a solid room, and we explain the trade-off honestly.
Book a free site visit in Wiltshire
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.