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 Northumberland?
In Northumberland, a glazed extension typically costs £2,500–£3,800 per m² of floor area, including VAT at 20% (standard rate). For a typical 18 m² project that is roughly £45,000–£68,500. The guide for Northumberland reflects typical costs in the North East, roughly 10% below the UK-wide figure. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (13 m²) | £32,500–£49,500 |
| Typical project (18 m²) | £45,000–£68,500 |
| Larger project (25 m²) | £62,500–£95,000 |
| Rate per m² | £2,500–£3,800 |
What moves the price most:
- Glazing size, specification and lead time
- Steel framing
- Overheating and energy design
- Access for large glass panels
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 Northumberland?
Here is how the rules work for a glazed extension 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.
Building regulations approval comes from the council’s building control service or a registered building control approver. The work is inspected at key stages, such as foundations, drainage and insulation, and a completion certificate is issued at the end.
We check this for your address before design work starts, so there are no surprises later.
What we handle
From survey to sign-off, the job normally involves:
- Large-format sliding doors and fixed glazing
- Structural design for steel frames and glass supports
- Electrics, heating and finishes
- Contemporary design and planning drawings
- Foundations, walls and insulated roof
- Cladding or render finish
How long does it take?
Build time is typically 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 Northumberland
The North East has many terraced streets and post-war semis, where rear extensions and loft conversions are popular ways to gain space.
Towns we cover in Northumberland include Blyth, Cramlington, Ashington and Bedlington.
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
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 Northumberland
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.
How long does a glazed extension take in Northumberland?
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 Northumberland?
In Northumberland, a glazed extension typically costs £2,500–£3,800 per m² of floor area, including VAT at 20% (standard rate). A typical 18 m² project comes to roughly £45,000–£68,500. 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.
Is VAT charged?
Yes, VAT at the standard 20% rate applies to extensions. Our guide prices include it.