Glass box extensions across Lisburn
From the first sketch to final sign-off, we plan and build glass extensions in Lisburn and the surrounding County Antrim area.
- Guide price in LisburnFrom £25,500 inc VAT
- PlanningNI permitted development (rear 3–4 m) or planning
- Build time10–16 weeks on site
- Postcode districtsBT10, BT11, BT17, BT27, BT28
Planning rules that apply in Lisburn
In Northern Ireland the Planning (General Permitted Development) Order 2015 lets some single-storey rear extensions go ahead without planning permission, up to 3 m on a semi-detached or terraced house and 4 m on a detached house, within height and boundary limits. Larger, side and two-storey extensions normally need planning permission from the council, and building control approval is separate.
Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.
Northern Ireland has no Party Wall Act. Where work is on or close to a shared boundary, we agree access and protection with your neighbour in writing before work starts.
In Northern Ireland building control is run by the councils under the Building Regulations (Northern Ireland). We submit full plans or a building notice and book the inspections through to completion.
Applications are decided by your council, which handles local planning in Northern Ireland.
Local to Lisburn
Our survey diary covers Lisburn, including BT10, BT11, BT17, BT27, BT28. Neighbouring towns we cover include Belfast (7 miles), Castlereagh (7 miles), Newtownabbey (11 miles), Antrim (15 miles).
In Northern Ireland, extension projects follow the NI planning rules and council building control, which we account for from the first survey.
What we take care of
- Solar-control and low-energy glass specification
- Whole-house energy calculations where needed
- Planning drawings that show the glass detail
- Drainage details for frameless roofs
- Steel or glass beams and slim-frame glazing
Glass extension prices in Lisburn
For Lisburn we adjust our national guide rates by ×0.86, the factor we use for Northern Ireland. Figures include VAT; your written quote after the survey replaces them.
Typical rates in Lisburn: £2,580 to £4,990 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2 m × 4 m 8 m² | £25,500 – £31,000 | £25,500 – £32,500 | £29,500 – £40,000 |
| 3 m × 4 m 12 m² | £30,500 – £37,500 | £36,000 – £45,500 | £44,000 – £60,000 |
| 3 m × 6 m 18 m² | £46,000 – £56,000 | £54,000 – £68,500 | £66,500 – £90,000 |
For a figure based on your own dimensions, use our guide-price tool.
What happens next
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
Design and approvals
We produce the drawings and structural design, and manage the approvals so they are in place before work starts.
Fixed written price
The price is fixed in writing once the design is settled, with a clear programme and payment stages.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Questions people ask about glass extensions
Will my neighbours in Lisburn be involved?
If a planning application is needed, the council notifies neighbours. Where work is close to a shared boundary, we agree access and protection with them in writing.
Do I need building regulations approval in Lisburn?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Lisburn, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Are glass extensions cold in winter?
Modern double or triple glazing with warm-edge spacers and underfloor heating keeps them comfortable. They are not as warm as a solid room, and we explain the trade-off honestly.
How much does a glass extension cost?
Our guide range is about £2,580 to £4,990 per m² including VAT, because structural glass is made to order. A 12 m² standard-spec glass extension is typically £36,000 to £45,500 in Lisburn.
Book a free site visit in Lisburn
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.