Glass box extensions in Brighton: design, approvals and build
If you live in Brighton 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 BrightonFrom £33,500 inc VAT
- PlanningSame limits as single-storey rear; glazing checked for building regs
- Build time10–16 weeks on site
- Postcode districtsBN1, BN2, BN3, BN41
Glass extension prices in Brighton
Prices below are for Brighton, using the South East England factor of ×1.12. They are guide ranges including VAT for the build only, not a quote.
Typical rates in Brighton: £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 |
Want a range for your exact size? The guide-price tool takes about a minute.
What is included
- Steel or glass beams and slim-frame glazing
- Planning drawings that show the glass detail
- Drainage details for frameless roofs
- Solar-control and low-energy glass specification
- Whole-house energy calculations where needed
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.
Planning rules that apply in Brighton
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 Brighton 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).
Local to Brighton
We cover Brighton and the postcode districts BN1, BN2, BN3, BN41. Neighbouring towns we cover include Hove (1 mile), Portslade (3 miles), Peacehaven (6 miles), Seaford (11 miles).
Just over the West Sussex border, Shoreham-by-Sea is about 6 miles away. In the South East, plenty of houses have already been extended once, which makes checking the remaining permitted development allowance an important early step.
How the project works
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
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
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
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Common questions in Brighton
Do you cover all of Brighton?
Yes. We cover Brighton and the surrounding parts of East Sussex. Site visits are free and there is no obligation.
Do I need building regulations approval in Brighton?
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 Brighton, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
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 Brighton.
Book a free site visit in Brighton
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.