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 Lisburn?
In Lisburn, a glazed extension typically costs £2,400–£3,600 per m² of floor area, including VAT at 20% (standard rate). For a typical 18 m² project that is roughly £43,000–£65,000. Building costs in Northern Ireland run about 14% below the UK average, and the figures for Lisburn are adjusted to reflect that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (13 m²) | £31,000–£47,000 |
| Typical project (18 m²) | £43,000–£65,000 |
| Larger project (25 m²) | £60,000–£90,000 |
| Rate per m² | £2,400–£3,600 |
The main things that change the cost:
- Lighting and finishes
- Access for large glass panels
- Cladding material
- Glazing size, specification and lead time
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 Lisburn?
Whether you need planning permission depends on your house and its location in Northern Ireland. In Northern Ireland the Planning (General Permitted Development) Order (Northern Ireland) 2015 allows single-storey rear extensions of up to 3 metres on attached houses and 4 metres on detached houses, no higher than 4 metres, with eaves no higher than 3 metres within 2 metres of a boundary. Houses with removed rights need planning permission, listed buildings need consent, and in conservation areas extensions must stay single-storey and must not come forward of the front or side walls.
In Northern Ireland building control approval comes from the council, usually through a full plans application or a building notice, with inspections during the work and a completion certificate at the end.
We check this for your address before design work starts, so there are no surprises later.
What we handle
The work we manage on a glazed extension:
- Foundations, walls and insulated roof
- Cladding or render finish
- Structural design for steel frames and glass supports
- Electrics, heating and finishes
- Building control sign-off
- Energy and overheating calculations where needed
How long does it take?
The build itself usually takes 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 Lisburn
Across Northern Ireland, bungalows and chalet bungalows are common, so loft conversions and rear extensions are popular projects.
Our Lisburn coverage includes postcode districts BT27 and BT28, and we also work in nearby places such as Belfast, Newtownabbey and Newtownards.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 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
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about glazed extensions in Lisburn
Do you build glazed extensions in Lisburn?
Yes. We build glazed extensions across Lisburn, including postcodes BT27 and BT28. Every project starts with a free home visit.
Is triple glazing necessary?
Not always. High-performance double glazing can meet the standards; triple glazing helps in exposed locations.
How much does a glazed extension cost in Lisburn?
In Lisburn, a glazed extension typically costs £2,400–£3,600 per m² of floor area, including VAT at 20% (standard rate). A typical 18 m² project comes to roughly £43,000–£65,000. Your fixed price depends on the survey and drawings.
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.
Do I need planning permission for a glazed extension in Lisburn?
In Northern Ireland the Planning (General Permitted Development) Order (Northern Ireland) 2015 allows single-storey rear extensions of up to 3 metres on attached houses and 4 metres on detached houses, no higher than 4 metres, with eaves no higher than 3 metres within 2 metres of a boundary. Houses with removed rights need planning permission, listed buildings need consent, and in conservation areas extensions must stay single-storey and must not come forward of the front or side walls.