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 Harwich?
In Harwich, a glazed extension typically costs £2,950–£4,450 per m² of floor area, including VAT at 20% (standard rate). For a typical 18 m² project that is roughly £53,000–£80,000. That range is adjusted for the East of England, where domestic building work typically costs around 6% above the national average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (13 m²) | £38,500–£58,000 |
| Typical project (18 m²) | £53,000–£80,000 |
| Larger project (25 m²) | £74,000–£111,000 |
| Rate per m² | £2,950–£4,450 |
Your quote will depend mainly on:
- Access for large glass panels
- Steel framing
- 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 Harwich?
Before anything is built in Harwich, 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.
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
From survey to sign-off, the job normally involves:
- Structural design for steel frames and glass supports
- Foundations, walls and insulated roof
- Electrics, heating and finishes
- Large-format sliding doors and fixed glazing
- Cladding or render finish
- 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. Allow time beforehand for drawings and approvals, usually 3 to 4 months.
Building in Harwich
Many towns in the East of England have estates built since the 1970s, where garage conversions and rear extensions are popular.
If your home is in Harwich or close by in Felixstowe, Ipswich and Clacton-on-Sea, a free home visit is the first step.
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 fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 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 Harwich
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 Harwich?
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.
How much does a glazed extension cost in Harwich?
In Harwich, a glazed extension typically costs £2,950–£4,450 per m² of floor area, including VAT at 20% (standard rate). A typical 18 m² project comes to roughly £53,000–£80,000. 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.
Can large glass panels be lifted in?
Some need a crane or glass-lifting robot. We plan access during design.