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 Wembley?
In Wembley, a glazed extension typically costs £3,650–£5,450 per m² of floor area, including VAT at 20% (standard rate). For a typical 18 m² project that is roughly £65,500–£98,000. That range is adjusted for London, where domestic building work typically costs around 30% above the national average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (13 m²) | £47,500–£71,000 |
| Typical project (18 m²) | £65,500–£98,000 |
| Larger project (25 m²) | £91,000–£136,000 |
| Rate per m² | £3,650–£5,450 |
The biggest cost drivers are:
- Access for large glass panels
- Lighting and finishes
- Glazing size, specification and lead time
- Steel framing
Use the guide price tool to see how size and specification change the figure, then ask for a written, itemised quote.
Do you need planning permission for a glazed extension in Wembley?
Before anything is built in Wembley, 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
From survey to sign-off, the job normally involves:
- Foundations, walls and insulated roof
- Large-format sliding doors and fixed glazing
- Contemporary design and planning drawings
- Electrics, heating and finishes
- Cladding or render finish
- Structural design for steel frames and glass supports
How long does it take?
Expect 12 to 16 weeks on site; glazing lead times can be 6 to 10 weeks. Before that, surveys, drawings and approvals usually take 3 to 4 months, longer if the council asks for changes.
Building in Wembley
Space is at a premium in London, so homeowners often build out into the side return or up into the roof rather than move.
Projects in Wembley (HA0) are surveyed in person before we quote, so the price reflects your actual property.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about glazed extensions in Wembley
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.
Do you build glazed extensions in Wembley?
Yes. We build glazed extensions across Wembley, including postcodes HA0. Every project starts with a free home visit.
How much does a glazed extension cost in Wembley?
In Wembley, a glazed extension typically costs £3,650–£5,450 per m² of floor area, including VAT at 20% (standard rate). A typical 18 m² project comes to roughly £65,500–£98,000. Your fixed price depends on the survey and drawings.
Is triple glazing necessary?
Not always. High-performance double glazing can meet the standards; triple glazing helps in exposed locations.
Is VAT charged?
Yes, VAT at the standard 20% rate applies to extensions. Our guide prices include it.
