Single-storey rear extensions for homes in Lisburn
A single-storey extension in Lisburn starts with the right design and the right approval route. We take care of both, then build it with our own project management.
- Guide price in LisburnFrom £18,000 inc VAT
- PlanningNI permitted development (rear 3–4 m) or planning
- Build time10–16 weeks on site
- Postcode districtsBT10, BT11, BT17, BT27, BT28
Extensions in and around Lisburn
Site visits are available across Lisburn (BT10, BT11, BT17, BT27, BT28). Nearby, we also take on projects in Belfast (7 miles), Castlereagh (7 miles), Newtownabbey (11 miles), Antrim (15 miles).
Just over the County Down border, Newtownards is about 15 miles away. In Northern Ireland, extension projects follow the NI planning rules and council building control, which we account for from the first survey.
Guide prices for 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: £1,500 to £2,920 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m 12 m² | £18,000 – £21,500 | £21,000 – £27,000 | £26,500 – £35,500 |
| 4 m × 5 m 20 m² | £30,000 – £35,500 | £35,000 – £45,000 | £44,500 – £58,500 |
| 5 m × 6 m 30 m² | £45,000 – £53,000 | £52,500 – £67,500 | £67,000 – £88,000 |
For a figure based on your own dimensions, use our guide-price tool.
Included in a typical project
- Planning route checked and the right approval obtained
- Walls, steel beams and the new opening into the house
- Foundations, drainage and groundworks
- Flat or pitched roof, rooflights or lantern
- Measured survey and design
Depth is the big decision. Every extra metre adds floor area but also takes garden and can push you out of permitted development. We draw the room at two or three depths so you can see the trade-off in space, light and cost before anything is fixed.
Planning and approvals 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.
Homes in conservation areas, areas of townscape character and listed buildings have tighter rules, so we always check the property's status and planning history before design 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.
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
We visit your Lisburn home, measure up, talk through what you want and check the planning position.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Your questions about a single-storey extension in Lisburn
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 you cover all of Lisburn?
Yes. We cover Lisburn and the surrounding parts of County Antrim. Site visits are free and there is no obligation.
How long does a single-storey extension take to build in Lisburn?
On site, typically 10 to 16 weeks once approvals are in place. Before that, allow 4–12 weeks design and approvals.
Flat roof or pitched roof?
Flat roofs give more headroom inside and suit lanterns and rooflights; pitched roofs can blend better with older houses. Both meet building regulations when built properly. See our flat roof and pitched roof pages for the details.
Can I stay in the house during the build?
Usually yes. Most of the work happens outside until the final weeks, when we open the rear wall. We plan that stage carefully and seal the opening with a temporary screen to keep dust down.
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.