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 Thornton-Cleveleys?
In Thornton-Cleveleys, 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. Prices across the North West are typically 6% below the UK average for this kind of work, which is reflected in the range for Thornton-Cleveleys. 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 biggest cost drivers are:
- Glazing size, specification and lead time
- Lighting and finishes
- Access for large glass panels
- Overheating and energy design
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 Thornton-Cleveleys?
The approval route for Thornton-Cleveleys 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
What we take care of:
- Cladding or render finish
- Structural design for steel frames and glass supports
- Energy and overheating calculations where needed
- Electrics, heating and finishes
- Large-format sliding doors and fixed glazing
- Building control sign-off
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 Thornton-Cleveleys
The North West has many brick terraces and inter-war semis, where kitchen extensions and dormer loft conversions add space without moving.
Thornton-Cleveleys sits in Lancashire, about 15 miles north-west of Preston. We cover the whole of Thornton-Cleveleys, including postcodes FY2 and FY5.
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
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about glazed extensions in Thornton-Cleveleys
Is VAT charged?
Yes, VAT at the standard 20% rate applies to extensions. Our guide prices include it.
How long do large glass panels take to arrive?
Often 6 to 10 weeks after final measurements, so we order them as soon as the structure is built.
Who approves a glazed extension in Thornton-Cleveleys?
Planning matters in Thornton-Cleveleys go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
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 Thornton-Cleveleys?
In Thornton-Cleveleys, 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.
