Glass box extensions for homes in Chelmsford
If you live in Chelmsford 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 ChelmsfordFrom £31,500 inc VAT
- PlanningSame limits as single-storey rear; glazing checked for building regs
- Build time10–16 weeks on site
- Postcode districtsCM1, CM2
Planning and approvals in Chelmsford
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 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).
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
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.
Working in Chelmsford
Site visits are available across Chelmsford (CM1, CM2). Nearby, we also take on projects in Billericay (8 miles), Witham (9 miles), Maldon (9 miles), Wickford (9 miles).
Bishop's Stortford, in Hertfordshire, is roughly 16 miles from Chelmsford and also on our list. The East of England mixes market-town terraces, inter-war semis and modern estates. Clay soils are common in parts of the region, which can affect foundation design.
Guide prices for Chelmsford
Prices below are for Chelmsford, using the East of England factor of ×1.06. They are guide ranges including VAT for the build only, not a quote.
Typical rates in Chelmsford: £3,180 to £6,150 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2 m × 4 m 8 m² | £31,500 – £38,500 | £31,500 – £40,000 | £36,000 – £49,500 |
| 3 m × 4 m 12 m² | £38,000 – £46,000 | £44,500 – £56,000 | £54,500 – £74,000 |
| 3 m × 6 m 18 m² | £57,000 – £69,000 | £66,500 – £84,000 | £82,000 – £111,000 |
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
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
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Your questions about a glass extension in Chelmsford
Will my neighbours in Chelmsford 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.
Do you cover all of Chelmsford?
Yes. We cover Chelmsford and the surrounding parts of Essex. 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 Chelmsford, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
How much does a glass extension cost?
Our guide range is about £3,180 to £6,150 per m² including VAT, because structural glass is made to order. A 12 m² standard-spec glass extension is typically £44,500 to £56,000 in Chelmsford.
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 Chelmsford
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.