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 Washington?
In Washington, 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. We start from a UK-wide guide and adjust it for the North East, where labour and materials are typically about 10% below average. 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 |
Your quote will depend mainly on:
- Steel framing
- Cladding material
- Access for large glass panels
- Glazing size, specification and lead time
A guide range is only a starting point: the guide price tool gives an instant figure for your size, and a free survey turns it into a fixed quote.
Do you need planning permission for a glazed extension in Washington?
The approval route for Washington is set by planning law 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.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
The work we manage on a glazed extension:
- Contemporary design and planning drawings
- Energy and overheating calculations where needed
- Building control sign-off
- Cladding or render finish
- Electrics, heating and finishes
- Structural design for steel frames and glass supports
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 Washington
The North East has many terraced streets and post-war semis, where rear extensions and loft conversions are popular ways to gain space.
If your home is in Washington or close by in Chester-le-Street, Houghton-Le-Spring and Hebburn, a free home visit is the first step.
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
Planning or permitted development confirmation, building regulations and any party wall matters.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about glazed extensions in Washington
Is triple glazing necessary?
Not always. High-performance double glazing can meet the standards; triple glazing helps in exposed locations.
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 Washington?
In Washington, 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.
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.
Do you build glazed extensions in Washington?
Yes. We build glazed extensions across Washington, including postcodes NE37 and NE38. Every project starts with a free home visit.