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 Cambridge?
In Cambridge, 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. Prices across the East of England are typically 6% above the UK average for this kind of work, which is reflected in the range for Cambridge. 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 main things that change the cost:
- Glazing and finishes
- Condition of the existing structure
- Planning conditions and ecology
- Access to the site
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 Cambridge?
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.
We check this for your address before design work starts, so there are no surprises later.
What we handle
The work we manage on a barn conversion:
- Insulation that respects the existing fabric
- Structural survey and feasibility
- Services, drainage and septic or treatment plant
- Planning or prior approval application
- Building control completion
- Structural repairs and new floor slab
How long does it take?
Expect 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 Cambridge
Many towns in the East of England have estates built since the 1970s, where garage conversions and rear extensions are popular.
From CB5 outwards, we take on projects throughout Cambridge and the surrounding parts of Cambridgeshire.
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 Cambridge
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 long does a barn conversion take?
Typically 6 to 12 months on site, depending on the building’s condition.
How much does a barn conversion cost in Cambridge?
In Cambridge, 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.
Who approves a barn conversion in Cambridge?
Planning matters in Cambridge go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
