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 South Glamorgan?
In South Glamorgan, a barn conversion typically costs £1,650–£2,750 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 £247,500–£412,500. We start from a UK-wide guide and adjust it for Wales, where labour and materials are typically about 8% below average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (105 m²) | £173,000–£289,000 |
| Typical project (150 m²) | £247,500–£412,500 |
| Larger project (210 m²) | £346,500–£577,500 |
| Rate per m² | £1,650–£2,750 |
The biggest cost drivers are:
- Condition of the existing structure
- Access to the site
- Services and drainage
- Insulation approach
Use the guide price tool to see how size and specification change the figure, then ask for a written, itemised quote.
Do you need planning permission for a barn conversion in South Glamorgan?
The approval route for South Glamorgan is set by planning law in Wales. In Wales converting a barn into a home needs full planning permission; there is no equivalent of the English Class Q route.
Building regulations in Wales are set by the Welsh Government. Approval comes from the council’s building control service or a registered building control approver, 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
On a typical barn conversion we handle:
- New roof covering where needed
- Building control completion
- Insulation that respects the existing fabric
- Structural survey and feasibility
- Planning or prior approval application
- Structural repairs and new floor slab
How long does it take?
The build itself usually takes 6 to 12 months on site depending on condition. Allow time beforehand for drawings and approvals, usually 4 to 9 months.
Building in South Glamorgan
Terraced houses in Welsh towns often have narrow plots, which suits rear and side return extensions and rear dormers.
Towns we cover in South Glamorgan include Cardiff, Barry and Penarth.
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
Design and pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 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 South Glamorgan
Do I need planning permission for a barn conversion in South Glamorgan?
In Wales converting a barn into a home needs full planning permission; there is no equivalent of the English Class Q route.
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 South Glamorgan?
In South Glamorgan, a barn conversion typically costs £1,650–£2,750 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 £247,500–£412,500. Your fixed price depends on the survey and drawings.
Do you build barn conversions in South Glamorgan?
Yes. We build barn conversions across South Glamorgan, including postcodes CF3, CF32, CF35, CF5 and CF61. Every project starts with a free home visit.
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.
What about drainage without mains sewer?
A sewage treatment plant can be installed, subject to the environmental regulator’s rules where you live.
