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 Runcorn?
In Runcorn, a glazed extension typically costs £2,650–£3,950 per m² of floor area, including VAT at 20% (standard rate). For a typical 18 m² project that is roughly £47,500–£71,000. The guide for Runcorn reflects typical costs in the North West, roughly 6% below the UK-wide figure. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (13 m²) | £34,500–£51,500 |
| Typical project (18 m²) | £47,500–£71,000 |
| Larger project (25 m²) | £66,000–£99,000 |
| Rate per m² | £2,650–£3,950 |
The main things that change the cost:
- Glazing size, specification and lead time
- Cladding material
- Access for large glass panels
- Lighting and finishes
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 Runcorn?
The approval route for Runcorn 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.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
On a typical glazed extension we handle:
- Building control sign-off
- Contemporary design and planning drawings
- Energy and overheating calculations where needed
- Large-format sliding doors and fixed glazing
- Foundations, walls and insulated roof
- Structural design for steel frames and glass supports
How long does it take?
Expect 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 Runcorn
Terraced streets across the North West often suit rear dormers and single-storey kitchen extensions.
From WA7 outwards, we take on projects throughout Runcorn and the surrounding parts of Cheshire.
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 pricing
Design options, then a fixed quote based on the chosen drawings and 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 Runcorn
Is VAT charged?
Yes, VAT at the standard 20% rate applies to extensions. Our guide prices include it.
Is triple glazing necessary?
Not always. High-performance double glazing can meet the standards; triple glazing helps in exposed locations.
How much does a glazed extension cost in Runcorn?
In Runcorn, a glazed extension typically costs £2,650–£3,950 per m² of floor area, including VAT at 20% (standard rate). A typical 18 m² project comes to roughly £47,500–£71,000. 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.
How long does a glazed extension take in Runcorn?
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.