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 St Albans?
In St Albans, a barn conversion typically costs £1,900–£3,200 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 £285,000–£480,000. That range is adjusted for the East of England, where domestic building work typically costs around 6% above the national average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (105 m²) | £199,500–£336,000 |
| Typical project (150 m²) | £285,000–£480,000 |
| Larger project (210 m²) | £399,000–£672,000 |
| Rate per m² | £1,900–£3,200 |
The biggest cost drivers are:
- Condition of the existing structure
- Insulation approach
- Access to the site
- Services and drainage
A guide range is only a starting point: the guide price tool gives an instant figure for your size, and a free survey turns it into a fixed quote.
Do you need planning permission for a barn conversion in St Albans?
Whether you need planning permission depends on your house and its location 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.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
The work we manage on a barn conversion:
- Services, drainage and septic or treatment plant
- Insulation that respects the existing fabric
- Ecology and bat survey coordination
- Building control completion
- Structural repairs and new floor slab
- Structural survey and feasibility
How long does it take?
Expect 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 St Albans
Across the East of England, 1930s and post-war semis, newer estates and rural cottages all feature, each with different extension and loft options.
St Albans sits in Hertfordshire, about 11 miles west of Hertford. We cover the whole of St Albans, including postcodes AL1 and AL3.
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 sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about barn conversions in St Albans
What about drainage without mains sewer?
A sewage treatment plant can be installed, subject to the environmental regulator’s rules where you live.
How much does a barn conversion cost in St Albans?
In St Albans, a barn conversion typically costs £1,900–£3,200 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 £285,000–£480,000. Your fixed price depends on the survey and drawings.
Do you build barn conversions in St Albans?
Yes. We build barn conversions across St Albans, including postcodes AL1 and AL3. Every project starts with a free home visit.
Do I need a bat survey?
Very often. Barns are common bat roosts, and planning authorities usually ask for an ecology survey.
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.
