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 Gainsborough?
In Gainsborough, a glazed extension typically costs £2,650–£4,000 per m² of floor area, including VAT at 20% (standard rate). For a typical 18 m² project that is roughly £47,500–£72,000. We start from a UK-wide guide and adjust it for the East Midlands, where labour and materials are typically about 5% below average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (13 m²) | £34,500–£52,000 |
| Typical project (18 m²) | £47,500–£72,000 |
| Larger project (25 m²) | £66,000–£100,000 |
| Rate per m² | £2,650–£4,000 |
The main things that change the cost:
- Access for large glass panels
- Glazing size, specification and lead time
- Steel framing
- Lighting and finishes
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 Gainsborough?
Approvals for a glazed extension in Gainsborough follow the rules for 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
From survey to sign-off, the job normally involves:
- Cladding or render finish
- 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
- Contemporary design and planning drawings
How long does it take?
Allow 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 Gainsborough
In the East Midlands, many estates built since the 1960s have integral garages that convert well into a study or bedroom.
Our Gainsborough coverage includes postcode districts DN21, and we also work in nearby places such as Retford, Scunthorpe and Lincoln.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about glazed extensions in Gainsborough
Is triple glazing necessary?
Not always. High-performance double glazing can meet the standards; triple glazing helps in exposed locations.
How long does a glazed extension take in Gainsborough?
Typically 12 to 16 weeks on site; glazing lead times can be 6 to 10 weeks. Design and approvals beforehand usually take 3 to 4 months.
How much does a glazed extension cost in Gainsborough?
In Gainsborough, a glazed extension typically costs £2,650–£4,000 per m² of floor area, including VAT at 20% (standard rate). A typical 18 m² project comes to roughly £47,500–£72,000. Your fixed price depends on the survey and drawings.
Can large glass panels be lifted in?
Some need a crane or glass-lifting robot. We plan access during design.
Will a glass extension be too hot in summer?
It can be if poorly designed. Solar-control glass, roof overhangs and opening vents reduce overheating, and building regulations may require calculations to show the design works.