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 Dartford?
In Dartford, a barn conversion typically costs £2,000–£3,350 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 £300,000–£502,500. The guide for Dartford reflects typical costs in the South East, roughly 12% above the UK-wide figure. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (105 m²) | £210,000–£352,000 |
| Typical project (150 m²) | £300,000–£502,500 |
| Larger project (210 m²) | £420,000–£703,500 |
| Rate per m² | £2,000–£3,350 |
The main things that change the cost:
- Planning conditions and ecology
- Insulation approach
- 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 Dartford?
Here is how the rules work for a barn conversion in England. In England converting an agricultural building into a home needs either full planning permission or prior approval under Class Q of the permitted development rules, which limits floor space and the number of homes. Listed barns also need listed building consent.
Building regulations approval comes from the council’s building control service or a registered building control approver. The work is inspected at key stages, such as foundations, drainage and insulation, and a completion certificate is issued at the end.
We check this for your address before design work starts, so there are no surprises later.
What we handle
From survey to sign-off, the job normally involves:
- Building control completion
- Planning or prior approval application
- Insulation that respects the existing fabric
- Services, drainage and septic or treatment plant
- New roof covering where needed
- Ecology and bat survey coordination
How long does it take?
Expect 6 to 12 months on site depending on condition. Allow time beforehand for drawings and approvals, usually 4 to 9 months.
Building in Dartford
Commuter towns across the South East have many 1930s and post-war semis that suit rear extensions and hip-to-gable loft conversions.
From DA1 outwards, we take on projects throughout Dartford and the surrounding parts of Kent.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 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 sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about barn conversions in Dartford
How much does a barn conversion cost in Dartford?
In Dartford, a barn conversion typically costs £2,000–£3,350 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 £300,000–£502,500. Your fixed price depends on the survey and drawings.
Who approves a barn conversion in Dartford?
Planning matters in Dartford go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
Do I need a bat survey?
Very often. Barns are common bat roosts, and planning authorities usually ask for an ecology survey.
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.
How long does a barn conversion take?
Typically 6 to 12 months on site, depending on the building’s condition.
