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 County Down?
In County Down, 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:
- Services and drainage
- Glazing and finishes
- Planning conditions and ecology
- Access to the site
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 County Down?
Before anything is built in County Down, we confirm which approvals apply 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.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
What we take care of:
- Building control completion
- Ecology and bat survey coordination
- Structural repairs and new floor slab
- Planning or prior approval application
- Structural survey and feasibility
- New roof covering where needed
How long does it take?
The build itself usually takes 6 to 12 months on site depending on condition. Design and approvals come first and typically take 4 to 9 months, depending on the approval route.
Building in County Down
Across Northern Ireland, bungalows and chalet bungalows are common, so loft conversions and rear extensions are popular projects.
Towns we cover in County Down include Bangor, Newtownards, Newry, Banbridge and Downpatrick.
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 in place
We handle planning, building control and neighbour notices before work starts.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about barn conversions in County Down
What about drainage without mains sewer?
A sewage treatment plant can be installed, subject to the environmental regulator’s rules where you live.
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.
Do I need a bat survey?
Very often. Barns are common bat roosts, and planning authorities usually ask for an ecology survey.
How long does a barn conversion take in County Down?
Typically 6 to 12 months on site depending on condition. Design and approvals beforehand usually take 4 to 9 months.
How much does a barn conversion cost in County Down?
In County Down, 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.
Do I need planning permission for a barn conversion in County Down?
In Northern Ireland a barn conversion needs planning permission; planning policy supports reusing suitable rural buildings.
