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 Eastleigh?
In Eastleigh, a glazed extension typically costs £3,150–£4,700 per m² of floor area, including VAT at 20% (standard rate). For a typical 18 m² project that is roughly £56,500–£84,500. That range is adjusted for the South East, where domestic building work typically costs around 12% above the national average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (13 m²) | £41,000–£61,000 |
| Typical project (18 m²) | £56,500–£84,500 |
| Larger project (25 m²) | £79,000–£117,500 |
| Rate per m² | £3,150–£4,700 |
What moves the price most:
- Overheating and energy design
- Cladding material
- Access for large glass panels
- Steel framing
Your exact price depends on the survey and drawings. The guide price tool gives a quick range in the meantime.
Do you need planning permission for a glazed extension in Eastleigh?
Whether you need planning permission depends on your house and its location 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.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
Handled as part of most glazed extensions:
- Large-format sliding doors and fixed glazing
- Electrics, heating and finishes
- Structural design for steel frames and glass supports
- Cladding or render finish
- Energy and overheating calculations where needed
- Contemporary design and planning drawings
How long does it take?
Expect 12 to 16 weeks on site; glazing lead times can be 6 to 10 weeks. Allow time beforehand for drawings and approvals, usually 3 to 4 months.
Building in Eastleigh
The South East has a broad mix of housing, from Victorian terraces in the towns to post-war semis and newer estates, so extension types vary street by street.
If your home is in Eastleigh or close by in Southampton, Winchester and Totton, a free home visit is the first step.
How it works
- 01
Free visit
We look at the property, talk through what you want and measure up. There is no charge and no obligation.
- 02
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about glazed extensions in Eastleigh
Is VAT charged?
Yes, VAT at the standard 20% rate applies to extensions. Our guide prices include it.
Can large glass panels be lifted in?
Some need a crane or glass-lifting robot. We plan access during design.
Do you build glazed extensions in Eastleigh?
Yes. We build glazed extensions across Eastleigh, including postcodes SO50 and SO97. Every project starts with a free home visit.
Is triple glazing necessary?
Not always. High-performance double glazing can meet the standards; triple glazing helps in exposed locations.
How much does a glazed extension cost in Eastleigh?
In Eastleigh, a glazed extension typically costs £3,150–£4,700 per m² of floor area, including VAT at 20% (standard rate). A typical 18 m² project comes to roughly £56,500–£84,500. Your fixed price depends on the survey and drawings.
