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 Weymouth?
In Weymouth, a barn conversion typically costs £1,850–£3,050 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 £277,500–£457,500. Building costs in the South West are close to the UK average, so the figures for Weymouth are close to our national guide. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (105 m²) | £194,000–£320,000 |
| Typical project (150 m²) | £277,500–£457,500 |
| Larger project (210 m²) | £388,500–£640,500 |
| Rate per m² | £1,850–£3,050 |
The main things that change the cost:
- Access to the site
- Glazing and finishes
- Insulation approach
- Planning conditions and ecology
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 Weymouth?
The approval route for Weymouth is set by planning law 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.
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:
- Ecology and bat survey coordination
- Services, drainage and septic or treatment plant
- New roof covering where needed
- Insulation that respects the existing fabric
- Planning or prior approval application
- Structural repairs and new floor slab
How long does it take?
Build time is typically 6 to 12 months on site depending on condition. Allow time beforehand for drawings and approvals, usually 4 to 9 months.
Building in Weymouth
In parts of the South West, protected landscapes and conservation areas shape what can be built, so materials and roof forms are chosen carefully.
Projects in Weymouth (DT3 and DT4) are surveyed in person before we quote, so the price reflects your actual property.
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 Weymouth
How much does a barn conversion cost in Weymouth?
In Weymouth, a barn conversion typically costs £1,850–£3,050 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 £277,500–£457,500. Your fixed price depends on the survey and drawings.
How long does a barn conversion take in Weymouth?
Typically 6 to 12 months on site depending on condition. Design and approvals beforehand usually take 4 to 9 months.
Do I need planning permission for a barn conversion?
Yes. A barn conversion needs planning permission or, in England only, prior approval under the agricultural permitted development rules where the building qualifies. Listed barns also need listed building consent.
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.
