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 Spalding?
In Spalding, 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. That range is adjusted for the East Midlands, where domestic building work typically costs around 5% below the national 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
- Overheating and energy design
- Cladding material
- 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 Spalding?
Before anything is built in Spalding, 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.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
On a typical glazed extension we handle:
- Foundations, walls and insulated roof
- Cladding or render finish
- Large-format sliding doors and fixed glazing
- Structural design for steel frames and glass supports
- Building control sign-off
- Energy and overheating calculations where needed
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. Allow time beforehand for drawings and approvals, usually 3 to 4 months.
Building in Spalding
The East Midlands has a mix of red-brick terraces, inter-war semis and newer estates, so rear extensions and garage conversions are common projects.
Spalding sits in Lincolnshire, about 34 miles south-east of Lincoln. We cover the whole of Spalding, including postcodes PE11.
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
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 Spalding
Does it need planning permission?
The same rules as other extensions apply, but contemporary designs in conservation areas are assessed carefully. We discuss the design approach with you before applying.
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.
Is triple glazing necessary?
Not always. High-performance double glazing can meet the standards; triple glazing helps in exposed locations.
Do you build glazed extensions in Spalding?
Yes. We build glazed extensions across Spalding, including postcodes PE11. Every project starts with a free home visit.
How much does a glazed extension cost in Spalding?
In Spalding, 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.
