Glass box extensions for homes in Finchley
If you live in Finchley 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 FinchleyFrom £39,000 inc VAT
- PlanningSame limits as single-storey rear; glazing checked for building regs
- Build time10–16 weeks on site
- Postcode districtsN2, N3, N12, NW4, NW7
Is a glass extension right for your house?
- Garden-facing dining rooms
- Small infill spaces and side returns
- Period and listed-style houses where a light touch is wanted
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.
Glass extension prices in Finchley
Prices below are for Finchley, using the London factor of ×1.3. They are guide ranges including VAT for the build only, not a quote.
Typical rates in Finchley: £3,900 to £7,540 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2 m × 4 m 8 m² | £39,000 – £47,000 | £39,000 – £49,500 | £44,500 – £60,500 |
| 3 m × 4 m 12 m² | £46,500 – £56,500 | £54,500 – £69,000 | £67,000 – £90,500 |
| 3 m × 6 m 18 m² | £70,000 – £84,500 | £81,500 – £103,000 | £100,500 – £136,000 |
Try the guide-price tool to see a range for your own size and finish.
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.
Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.
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 Finchley
We cover Finchley and the postcode districts N2, N3, N12, NW4, NW7, NW11. Neighbouring towns we cover include Golders Green (2 miles), Friern Barnet (2 miles), Muswell Hill (2 miles), Cricklewood (3 miles).
In London, space is at a premium and gardens are often short, so side returns, wraparounds and carefully planned rear extensions tend to make the most of every metre.
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
Once the layout is agreed, we deal with the council: planning permission or written confirmation that none is needed, plus building control.
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.
Common questions in Finchley
Will my neighbours in Finchley 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 I need building regulations approval in Finchley?
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 Finchley, 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 £3,900 to £7,540 per m² including VAT, because structural glass is made to order. A 12 m² standard-spec glass extension is typically £54,500 to £69,000 in Finchley.
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 Finchley
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.