What is a barn conversion?

A barn conversion turns an agricultural or rural building into a home while keeping its character: the brick or stone walls, roof timbers and large openings. It involves structural repair, insulation, new services and often a new floor slab.
How much does a barn conversion cost in Lisburn?
In Lisburn, a barn conversion typically costs £1,550–£2,600 per m² of floor area, including VAT at usually 5% (reduced rate for creating a new dwelling). For a typical 150 m² project that is roughly £232,500–£390,000. That range is adjusted for Northern Ireland, where domestic building work typically costs around 14% below the national average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (105 m²) | £163,000–£273,000 |
| Typical project (150 m²) | £232,500–£390,000 |
| Larger project (210 m²) | £325,500–£546,000 |
| Rate per m² | £1,550–£2,600 |
The main things that change the cost:
- Planning conditions and ecology
- Access to the site
- Insulation approach
- Services and drainage
For a figure based on your own measurements, try the guide price tool, then book a free home visit for a fixed quote.
Do you need planning permission for a barn conversion in Lisburn?
Here is how the rules work for a barn conversion in Northern Ireland. In Northern Ireland a barn conversion needs planning permission; planning policy supports reusing suitable rural buildings.
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.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
Handled as part of most barn conversions:
- Structural survey and feasibility
- Ecology and bat survey coordination
- Insulation that respects the existing fabric
- Building control completion
- Services, drainage and septic or treatment plant
- Structural repairs and new floor slab
How long does it take?
Expect 6 to 12 months on site depending on condition. Before that, surveys, drawings and approvals usually take 4 to 9 months, longer if the council asks for changes.
Building in Lisburn
Northern Ireland has many detached and semi-detached homes on generous plots, which suits single-storey rear extensions and garage conversions.
From BT27 outwards, we take on projects throughout Lisburn and the surrounding parts of County Antrim.
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
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 barn conversions in Lisburn
Do I need planning permission for a barn conversion in Lisburn?
In Northern Ireland a barn conversion needs planning permission; planning policy supports reusing suitable rural buildings.
Can I get a mortgage for a barn conversion?
Specialist self-build and conversion mortgages release money in stages. We can provide the staged costings lenders ask for.
Is VAT reduced on a barn conversion?
Usually yes. Converting a non-residential building into a dwelling normally qualifies for the reduced 5% VAT rate on building work. Our guide prices assume this rate.
What about drainage without mains sewer?
A sewage treatment plant can be installed, subject to the environmental regulator’s rules where you live.
How much does a barn conversion cost in Lisburn?
In Lisburn, a barn conversion typically costs £1,550–£2,600 per m² of floor area, including VAT at usually 5% (reduced rate for creating a new dwelling). A typical 150 m² project comes to roughly £232,500–£390,000. Your fixed price depends on the survey and drawings.
How long does a barn conversion take in Lisburn?
Typically 6 to 12 months on site depending on condition. Design and approvals beforehand usually take 4 to 9 months.
