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 Plymouth?
In Plymouth, a glazed extension typically costs £2,850–£4,300 per m² of floor area, including VAT at 20% (standard rate). For a typical 18 m² project that is roughly £51,500–£77,500. Building costs in the South West are close to the UK average, so the figures for Plymouth are close to our national guide. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (13 m²) | £37,000–£56,000 |
| Typical project (18 m²) | £51,500–£77,500 |
| Larger project (25 m²) | £71,000–£107,500 |
| Rate per m² | £2,850–£4,300 |
What moves the price most:
- Cladding material
- Lighting and finishes
- Overheating and energy design
- 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 Plymouth?
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.
We check this for your address before design work starts, so there are no surprises later.
What we handle
What we take care of:
- Structural design for steel frames and glass supports
- Building control sign-off
- Large-format sliding doors and fixed glazing
- Electrics, heating and finishes
- Contemporary design and planning drawings
- Cladding or render finish
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 Plymouth
The South West mixes stone and render cottages with post-war and newer estates, and local materials matter more here when matching an extension.
We work across Plymouth and neighbouring areas such as Paignton, Newton Abbot and St Austell. Postcodes we cover in Plymouth include PL2 and PL4.
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 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 Plymouth
Do you build glazed extensions in Plymouth?
Yes. We build glazed extensions across Plymouth, including postcodes PL2 and PL4. Every project starts with a free home visit.
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.
Can large glass panels be lifted in?
Some need a crane or glass-lifting robot. We plan access during design.
How much does a glazed extension cost in Plymouth?
In Plymouth, a glazed extension typically costs £2,850–£4,300 per m² of floor area, including VAT at 20% (standard rate). A typical 18 m² project comes to roughly £51,500–£77,500. Your fixed price depends on the survey and drawings.
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.
