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 Canterbury?
In Canterbury, a glazed extension typically costs £3,150–£4,700 per m² of floor area, including VAT at 20% (standard rate). For a typical 18 m² project that is roughly £56,500–£84,500. That range is adjusted for the South East, where domestic building work typically costs around 12% above the national average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (13 m²) | £41,000–£61,000 |
| Typical project (18 m²) | £56,500–£84,500 |
| Larger project (25 m²) | £79,000–£117,500 |
| Rate per m² | £3,150–£4,700 |
What moves the price most:
- Overheating and energy design
- Lighting and finishes
- Cladding material
- Steel framing
For a figure based on your own measurements, try the guide price tool, then book a free home visit for a fixed quote.
Do you need planning permission for a glazed extension in Canterbury?
The approval route for Canterbury 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.
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.
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:
- Large-format sliding doors and fixed glazing
- Building control sign-off
- Energy and overheating calculations where needed
- Structural design for steel frames and glass supports
- Electrics, heating and finishes
- Foundations, walls and insulated roof
How long does it take?
Allow 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 Canterbury
Commuter towns across the South East have many 1930s and post-war semis that suit rear extensions and hip-to-gable loft conversions.
Our Canterbury coverage includes postcode districts CT1, and we also work in nearby places such as Whitstable, Herne Bay and Faversham.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 02
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about glazed extensions in Canterbury
How much does a glazed extension cost in Canterbury?
In Canterbury, a glazed extension typically costs £3,150–£4,700 per m² of floor area, including VAT at 20% (standard rate). A typical 18 m² project comes to roughly £56,500–£84,500. Your fixed price depends on the survey and drawings.
Is triple glazing necessary?
Not always. High-performance double glazing can meet the standards; triple glazing helps in exposed locations.
Who approves a glazed extension in Canterbury?
Planning matters in Canterbury go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
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.
Is VAT charged?
Yes, VAT at the standard 20% rate applies to extensions. Our guide prices include it.