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 Derry?
In Derry, 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 |
Your quote will depend mainly on:
- Insulation approach
- Planning conditions and ecology
- Condition of the existing structure
- 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 Derry?
Approvals for a barn conversion in Derry follow the rules for 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.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
The work we manage on a barn conversion:
- New roof covering where needed
- Structural repairs and new floor slab
- Services, drainage and septic or treatment plant
- Insulation that respects the existing fabric
- Building control completion
- Ecology and bat survey coordination
How long does it take?
Build time is typically 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 Derry
Across Northern Ireland, bungalows and chalet bungalows are common, so loft conversions and rear extensions are popular projects.
Our Derry coverage includes postcode districts BT47, and we also work in nearby places such as Strabane, Limavady and Coleraine.
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
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about barn conversions in Derry
Do I need a bat survey?
Very often. Barns are common bat roosts, and planning authorities usually ask for an ecology survey.
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.
How much does a barn conversion cost in Derry?
In Derry, 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 Derry?
In Northern Ireland a barn conversion needs planning permission; planning policy supports reusing suitable rural buildings.
Who approves a barn conversion in Derry?
Planning matters in Derry go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.