Glass box extensions across Horley
If you live in Horley and want more space without moving, a glass extension is one of the most practical ways to get it. We handle the drawings, approvals and the build.
- Guide price in HorleyFrom £33,500 inc VAT
- PlanningSame limits as single-storey rear; glazing checked for building regs
- Build time10–16 weeks on site
- Postcode districtsRH6

Who a glass extension suits
- Period and listed-style houses where a light touch is wanted
- Garden-facing dining rooms
- Small infill spaces and side returns
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.
What should I budget for a glass extension in Horley?
Labour and material costs vary across the UK, so for Horley we use our South East England factor (×1.12). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Horley: £3,360 to £6,500 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2 m × 4 m 8 m² | £33,500 – £40,500 | £33,500 – £42,500 | £38,500 – £52,000 |
| 3 m × 4 m 12 m² | £40,000 – £48,500 | £47,000 – £59,500 | £57,500 – £78,000 |
| 3 m × 6 m 18 m² | £60,000 – £73,000 | £70,500 – £89,000 | £86,500 – £117,000 |
For a figure based on your own dimensions, use our guide-price tool.
Covering Horley
Site visits are available across Horley (RH6). Nearby, we also take on projects in Redhill (5 miles), Reigate (5 miles), Caterham (8 miles), Banstead (10 miles).
Just over the West Sussex border, Crawley is about 4 miles away. Homes across the South East range from Victorian terraces in the older town centres to large detached houses on the edges, so the right extension type varies street by street.
Will the council need to approve it?
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.
The planning position for a specific Horley address depends on its history and any designations, which is why we check it at the first visit.
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).
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
First, a site visit: we look at the house, garden, access and drains and listen to what you need.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Questions people ask about glass extensions
Do you cover all of Horley?
Yes. We cover Horley and the surrounding parts of Surrey. 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 Horley, 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 Horley 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.
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.
How much does a glass extension cost?
Our guide range is about £3,360 to £6,500 per m² including VAT, because structural glass is made to order. A 12 m² standard-spec glass extension is typically £47,000 to £59,500 in Horley.
Book a free site visit in Horley
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.