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 Seaford?
In Seaford, 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. We start from a UK-wide guide and adjust it for the South East, where labour and materials are typically about 12% above 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:
- Cladding material
- Access for large glass panels
- Glazing size, specification and lead time
- Overheating and energy design
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 Seaford?
Before anything is built in Seaford, we confirm which approvals apply 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.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
On a typical glazed extension we handle:
- Contemporary design and planning drawings
- Electrics, heating and finishes
- Large-format sliding doors and fixed glazing
- Building control sign-off
- Energy and overheating calculations where needed
- Foundations, walls and insulated roof
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 Seaford
The South East has a broad mix of housing, from Victorian terraces in the towns to post-war semis and newer estates, so extension types vary street by street.
We work across Seaford and neighbouring areas such as Peacehaven, Rottingdean and Eastbourne. Postcodes we cover in Seaford include BN25.
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 in place
We handle planning, building control and neighbour notices before work starts.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about glazed extensions in Seaford
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 much does a glazed extension cost in Seaford?
In Seaford, 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.
Do you build glazed extensions in Seaford?
Yes. We build glazed extensions across Seaford, including postcodes BN25. Every project starts with a free home visit.
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.
Can large glass panels be lifted in?
Some need a crane or glass-lifting robot. We plan access during design.
