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 Hampstead?
In Hampstead, a glazed extension typically costs £3,650–£5,450 per m² of floor area, including VAT at 20% (standard rate). For a typical 18 m² project that is roughly £65,500–£98,000. The guide for Hampstead reflects typical costs in London, roughly 30% above the UK-wide figure. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (13 m²) | £47,500–£71,000 |
| Typical project (18 m²) | £65,500–£98,000 |
| Larger project (25 m²) | £91,000–£136,000 |
| Rate per m² | £3,650–£5,450 |
The biggest cost drivers are:
- Cladding material
- Access for large glass panels
- Glazing size, specification and lead time
- Steel framing
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 Hampstead?
Approvals for a glazed extension in Hampstead follow the rules for 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.
We check this for your address before design work starts, so there are no surprises later.
What we handle
From survey to sign-off, the job normally involves:
- Foundations, walls and insulated roof
- Large-format sliding doors and fixed glazing
- Cladding or render finish
- Contemporary design and planning drawings
- Structural design for steel frames and glass supports
- Building control sign-off
How long does it take?
Build time is typically 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 Hampstead
Many London boroughs have conservation areas and detailed design guides, so early design advice saves time at the planning stage.
Hampstead sits in Greater London, about 4 miles north-west of central London. We cover the whole of Hampstead, including postcodes NW3.
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
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 Hampstead
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 Hampstead?
In Hampstead, a glazed extension typically costs £3,650–£5,450 per m² of floor area, including VAT at 20% (standard rate). A typical 18 m² project comes to roughly £65,500–£98,000. Your fixed price depends on the survey and drawings.
Who approves a glazed extension in Hampstead?
Planning matters in Hampstead 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 triple glazing necessary?
Not always. High-performance double glazing can meet the standards; triple glazing helps in exposed locations.