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 Carmarthen?
In Carmarthen, a glazed extension typically costs £2,600–£3,850 per m² of floor area, including VAT at 20% (standard rate). For a typical 18 m² project that is roughly £47,000–£69,500. The guide for Carmarthen reflects typical costs in Wales, roughly 8% below the UK-wide figure. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (13 m²) | £34,000–£50,000 |
| Typical project (18 m²) | £47,000–£69,500 |
| Larger project (25 m²) | £65,000–£96,000 |
| Rate per m² | £2,600–£3,850 |
Your quote will depend mainly on:
- Lighting and finishes
- Overheating and energy design
- Steel framing
- Glazing size, specification and lead time
Use the guide price tool to see how size and specification change the figure, then ask for a written, itemised quote.
Do you need planning permission for a glazed extension in Carmarthen?
Approvals for a glazed extension in Carmarthen follow the rules for Wales. In Wales a single-storey rear extension is often permitted development: up to 4 metres beyond the rear wall and up to 4 metres high, with eaves no higher than 3 metres within 2 metres of a boundary and no more than half the land around the original house covered. Wales has no larger home extension prior approval route, so deeper extensions need a planning application, as do extensions to flats, listed buildings and houses whose rights have been removed.
Building regulations in Wales are set by the Welsh Government. Approval comes from the council’s building control service or a registered building control approver, with inspections during the work and a completion certificate at the end.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
What we take care of:
- Contemporary design and planning drawings
- Electrics, heating and finishes
- Foundations, walls and insulated roof
- Cladding or render finish
- Building control sign-off
- Energy and overheating calculations where needed
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 Carmarthen
Terraced houses in Welsh towns often have narrow plots, which suits rear and side return extensions and rear dormers.
Carmarthen sits in Dyfed. We cover the whole of Carmarthen, including postcodes SA31.
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 pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 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 Carmarthen
Do I need planning permission for a glazed extension in Carmarthen?
In Wales a single-storey rear extension is often permitted development: up to 4 metres beyond the rear wall and up to 4 metres high, with eaves no higher than 3 metres within 2 metres of a boundary and no more than half the land around the original house covered. Wales has no larger home extension prior approval route, so deeper extensions need a planning application, as do extensions to flats, listed buildings and houses whose rights have been removed.
Is triple glazing necessary?
Not always. High-performance double glazing can meet the standards; triple glazing helps in exposed locations.
Do you build glazed extensions in Carmarthen?
Yes. We build glazed extensions across Carmarthen, including postcodes SA31. 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.
How much does a glazed extension cost in Carmarthen?
In Carmarthen, a glazed extension typically costs £2,600–£3,850 per m² of floor area, including VAT at 20% (standard rate). A typical 18 m² project comes to roughly £47,000–£69,500. Your fixed price depends on the survey and drawings.
Can large glass panels be lifted in?
Some need a crane or glass-lifting robot. We plan access during design.
