What is a glazed extension?

A glazed or contemporary extension uses large panes of glass, slim aluminium frames and modern cladding to create a bright room that contrasts with the original house. Frameless corners, structural glass roofs and minimal sliding doors are typical features.
How much does a glazed extension cost in Bentley?
In Bentley, a glazed extension typically costs £2,600–£3,900 per m² of floor area, including VAT at 20% (standard rate). For a typical 18 m² project that is roughly £47,000–£70,000. That range is adjusted for Yorkshire and the Humber, where domestic building work typically costs around 7% below the national average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (13 m²) | £34,000–£50,500 |
| Typical project (18 m²) | £47,000–£70,000 |
| Larger project (25 m²) | £65,000–£97,500 |
| Rate per m² | £2,600–£3,900 |
The main things that change the cost:
- Overheating and energy design
- Cladding material
- Lighting and finishes
- Glazing size, specification and lead time
For a figure based on your own measurements, try the guide price tool, then book a free home visit for a fixed quote.
Do you need planning permission for a glazed extension in Bentley?
Before anything is built in Bentley, we confirm which approvals apply in England. In England a single-storey rear extension is often permitted development: broadly up to 3 metres deep on a semi-detached or terraced house and 4 metres on a detached house, no higher than 4 metres, with eaves no higher than 3 metres within 2 metres of a boundary, and covering no more than half the garden. The larger home extension scheme allows up to 6 or 8 metres if you notify the council first and neighbours have a chance to comment. In conservation areas, National Parks and National Landscapes the larger home extension route, side extensions and cladding are not permitted development. Flats and houses whose rights have been removed need a planning application, and listed buildings need listed building consent.
Where work involves a shared wall, building on the boundary, or digging foundations within 3 metres of a neighbour’s building and deeper than its foundations (or within 6 metres for deeper work), the Party Wall etc. Act 1996 applies and notices must be served before work starts.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
The work we manage on a glazed extension:
- Large-format sliding doors and fixed glazing
- Energy and overheating calculations where needed
- Foundations, walls and insulated roof
- Structural design for steel frames and glass supports
- Building control sign-off
- Cladding or render finish
How long does it take?
The build itself usually takes 12 to 16 weeks on site; glazing lead times can be 6 to 10 weeks. Design and approvals come first and typically take 3 to 4 months, depending on the approval route.
Building in Bentley
Yorkshire and the Humber has stone and brick terraces as well as inter-war and newer estates, so materials matching is an early design question.
Our Bentley coverage includes postcode districts DN5, and we also work in nearby places such as Doncaster, Adwick le Street and South Elmsall.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 03
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about glazed extensions in Bentley
Do you build glazed extensions in Bentley?
Yes. We build glazed extensions across Bentley, including postcodes DN5. Every project starts with a free home visit.
Is VAT charged?
Yes, VAT at the standard 20% rate applies to extensions. Our guide prices include it.
How much does a glazed extension cost in Bentley?
In Bentley, a glazed extension typically costs £2,600–£3,900 per m² of floor area, including VAT at 20% (standard rate). A typical 18 m² project comes to roughly £47,000–£70,000. Your fixed price depends on the survey and drawings.
How long do large glass panels take to arrive?
Often 6 to 10 weeks after final measurements, so we order them as soon as the structure is built.
Can large glass panels be lifted in?
Some need a crane or glass-lifting robot. We plan access during design.
