Luxury conversions

At Collstone Projects, we specialise in luxury property conversions across Somerset, Wiltshire, and the Cotswolds — transforming outbuildings, barns, lofts, and more into stunning residential or commercial spaces. Based in Warminster and working in areas like Bath, Frome, and Bruton, we manage every stage of your project from concept to completion, working closely with trusted architects and designers to bring your vision to life. Whether you're converting a heritage barn into a spa retreat or reimagining a loft as a high-end apartment, we deliver bespoke, high-spec results with complete project management and expert care.

Looking for something else? We also offer renovations and joinery.

We undertake all types of luxury property conversions, tailored to meet both aesthetic and functional goals — whether for private homes, guest accommodations, or commercial use. Our services include:

  • Barn conversions into homes, spas, studios or events spaces

  • Loft conversions for additional bedrooms, offices, or suites

  • Garage conversions for living space, gyms, or annexes

  • Outbuilding transformations into holiday lets, garden rooms or workspaces

  • Commercial-to-residential conversions with a bespoke, luxury finish

  • Listed property conversions with planning, conservation, and compliance managed

  • Full plumbing, heating, and structural adaptation for modern use

Every conversion is delivered with premium materials, expert craftsmanship, and a deep respect for the original structure. We ensure each space meets today’s standards while retaining its unique character.

Our conversion services

  • "Handled everything professionally from planning to completion — great team and an amazing result."

    Tanya Alfonso

  • "Efficient, dependable, and the finished product exceeded expectations."

    Curtis Langtree

  • "First-class workmanship and clear communication from start to finish."

    Alex Gray

In Pilton, we converted a historic barn into a fully functioning luxury spa. The project involved complex plumbing installations, structural adaptations, and a full interior and exterior redesign to incorporate a swimming pool, sauna and a high-end finish throughout. The result is a seamless blend of rustic charm and contemporary indulgence — a true countryside retreat.

Our commitment to sustainability

At Collstone Projects, we recognise the value in reimagining existing structures — not only to create stunning spaces, but also to reduce environmental impact.

Our approach to conversions includes:

  • Retaining and enhancing original building fabric

  • Sourcing sustainable and local materials

  • Maximising energy efficiency through insulation, glazing, and modern systems

  • Minimising waste with precise planning and responsible recycling

We're proud to support initiatives like Edventure Frome’s DIY Materials Shop, helping give surplus building materials a second life and empowering our community with sustainable skills.

You can view our full list of suppliers and partners here.

 FAQs

  • We convert barns, lofts, garages, outbuildings, and even commercial spaces into luxury homes, spas, outdoor kitchens, golf simulators and guest accommodation.

  • Many conversions do require planning permission, especially for listed or protected buildings. We handle all necessary permissions and liaise with planning authorities where needed.

  • Project timelines vary, but most conversions take several months from design to completion. We’ll provide a detailed schedule as part of your project plan.

  • Yes — we have experience with listed and heritage properties and understand the care, permissions, and materials required to maintain their integrity.

  • Costs depend on the building type and level of finish, but luxury conversions generally start from £1,800 to £3,000+ per square metre. We provide tailored quotes based on your requirements.

  • Property conversion involves transforming an existing structure — such as a barn, loft, garage, or commercial building — into a new, functional space. This could mean converting a barn into a luxury home, an outbuilding into a guest suite, or a garage into a self-contained annex. At Collstone Projects, we specialise in high-spec conversions that enhance both value and lifestyle.

  • The 4-year rule refers to UK planning legislation that allows certain unauthorised changes of use (like converting a garage into living space) to become lawful if the change has existed for four continuous years without enforcement action. However, this can be complex and doesn’t apply in all cases — especially in listed buildings or conservation areas. We advise checking with your local authority or letting us handle the permissions for you.

  • Rules for property conversions depend on the type of building, its location, and whether it's listed or in a conservation area. In general, you may need:

    • Planning permission (especially for structural changes or change of use)

    • Building Regulations approval

    • Listed building consent, if applicable
      At Collstone Projects, we manage all aspects of compliance to ensure your conversion meets all legal and structural requirements.