Glass box extensions in East Grinstead: design, approvals and build
Thinking about a glass extension for your East Grinstead home? Start with a free site visit: we measure up, check what the council will allow and give you honest guide figures on the day.
- Guide price in East GrinsteadFrom £33,500 inc VAT
- PlanningSame limits as single-storey rear; glazing checked for building regs
- Build time10–16 weeks on site
- Postcode districtsRH19
Glass extension prices in East Grinstead
Labour and material costs vary across the UK, so for East Grinstead we use our South East England factor (×1.12). The ranges include VAT and exclude design, structural and council fees.
Typical rates in East Grinstead: £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.
Is a glass extension right for your house?
- Garden-facing dining rooms
- Period and listed-style houses where a light touch is wanted
- Small infill spaces and side returns
Planning and approvals in East Grinstead
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 East Grinstead address depends on its history and any designations, which is why we check it at the first visit.
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).
Covering East Grinstead
We cover East Grinstead and the postcode districts RH19. Neighbouring towns we cover include Crawley (8 miles), Haywards Heath (10 miles), Burgess Hill (13 miles), Horsham (15 miles).
Horley, in Surrey, is roughly 7 miles from East Grinstead and also on our list. 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
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
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Glass extension questions answered
Do you cover all of East Grinstead?
Yes. We cover East Grinstead and the surrounding parts of West Sussex. Site visits are free and there is no obligation.
How long does a glass extension take to build in East Grinstead?
On site, typically 10 to 16 weeks once approvals are in place. Before that, allow 8–14 weeks design and approvals.
Do I need building regulations approval in East Grinstead?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
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 East Grinstead.
Book a free site visit in East Grinstead
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.