Lisburn, County Antrim
Semi-detached rear extension in Lisburn
Thinking about a semi-detached rear extension in Lisburn? Single or two-storey extensions for semi-detached houses, with side access and one party wall. Our team handles the drawings, the planning route and the build, and your contract is with one company throughout.
We cover Lisburn (BT17, BT27 and BT28) as part of our County Antrim work. Where a Lisburn semi already has a small lean-to at the back, we usually replace it rather than extend it.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a semi-detached rear extension cost in Lisburn?
Guide prices for a semi-detached rear extension in Lisburn start from our Northern Ireland rate of £1,650–£2,700 per square metre, including VAT. Northern Ireland prices are the lowest in our range.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £20,000–£32,500 |
| 4 m wide × 5 m deep (20 m²) | £33,000–£54,000 |
| 4 m wide × 6 m deep (24 m²) | £39,500–£64,500 |
Your written price follows a measured survey and an agreed design, so it reflects your house, not an average.
Do you need planning permission for a semi-detached rear extension in Lisburn?
Whether your semi-detached rear extension in Lisburn needs a planning application depends on its size, your house and any local restrictions.
Northern Ireland's permitted development rules allow a single-storey rear extension of 3 metres on terraced and semi-detached houses and 4 metres on detached houses, with a 4 metre height limit. Listed buildings, conservation areas and houses with removed rights need planning permission from the council.
Northern Ireland's 2015 Order allows a two-storey rear extension of up to 3 metres where at least 7 metres is left to the rear boundary. Anything larger, or in a conservation area, needs a planning application to the council.
Northern Ireland has no larger-extension prior approval route; anything beyond permitted development needs a planning application.
Conservation areas, Areas of Outstanding Natural Beauty and listed buildings restrict permitted development in Northern Ireland. We check your house's planning history and any conservation area before drawing, so the route is clear before you spend on plans.
What are homes in Lisburn like to extend?
Semis and detached houses are typical of Lisburn, and many have room for a rear extension within Northern Ireland's permitted development limits.
How a semi-detached rear extension in Lisburn comes together
Survey visit
We visit free of charge, measure up, check access, drainage and neighbours' extensions, and note what you want the room to do.
Options and costs
We draw layout options and price each one, so the budget shapes the design rather than surprising you later.
Planning and regulations
We take the design through the right planning route, then produce the construction drawings and engineer's calculations for council building control.
Written price, then build
Once the design and approvals are in place, you get a fixed written price and programme, and we build through to sign-off.
Semi-detached rear extensions near Lisburn
We also build rear extensions for semi-detached houses in nearby Belfast (6.7 miles) and Castlereagh (7.0 miles).
- Semi-detached rear extension in Belfast
- Semi-detached rear extension in Castlereagh
- Semi-detached rear extension in Dundonald
- Semi-detached rear extension in Newtownabbey
- Semi-detached rear extension in Holywood
Other work in Lisburn:
FAQ
Semi-detached rear extension questions in Lisburn
How long does a rear extension take to build in Lisburn?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
Is the site visit in Lisburn free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.
What if my neighbour has already extended?
That can make a matching depth easier to justify. We measure theirs at the survey.
Who will build my extension?
Vetted building teams working under contract to us. Your contract is with S&K Property Investments and Improvement Ltd for the design and the build.
Will I need a structural engineer?
Yes for the beam over the new opening and usually the foundations; we arrange them and their calculations go to building control.
What postcode areas do you cover around Lisburn?
Including BT17, BT27 and BT28, and the surrounding County Antrim area.