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 Windsor?
In Windsor, 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. Building costs in the South East run about 12% above the UK average, and the figures for Windsor are adjusted to reflect that. 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 biggest cost drivers are:
- Access to the site
- Planning conditions and ecology
- Insulation approach
- Glazing and finishes
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 Windsor?
Approvals for a barn conversion in Windsor follow the rules for 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
On a typical barn conversion we handle:
- Structural repairs and new floor slab
- Services, drainage and septic or treatment plant
- New roof covering where needed
- Structural survey and feasibility
- Building control completion
- Insulation that respects the existing fabric
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 Windsor
The South East has a broad mix of housing, from Victorian terraces in the towns to post-war semis and newer estates, so extension types vary street by street.
Windsor sits in Berkshire, about 16 miles east of Reading. We cover the whole of Windsor, including postcodes SL4.
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
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about barn conversions in Windsor
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.
Do I need a bat survey?
Very often. Barns are common bat roosts, and planning authorities usually ask for an ecology survey.
How long does a barn conversion take?
Typically 6 to 12 months on site, depending on the building’s condition.
Who approves a barn conversion in Windsor?
Planning matters in Windsor go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
How much does a barn conversion cost in Windsor?
In Windsor, 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.
