As Cornwall's capital, Truro and the mid-Cornwall countryside around it hold a wonderful mix of buildings to convert: granite-fronted cottages, Georgian townhouses, redundant Methodist chapels and the granite and cob agricultural barns of the lanes towards Probus, Tresillian and the Fal estuary. We bring the structural carpentry and joinery these conversions need right across the TR postcodes.
The farmland around Truro is dotted with granite and cob barns raised to house cattle and store the harvest, and many no longer earn their keep agriculturally. From Probus and Tresillian out towards Falmouth, Penryn and Redruth, these robust stone buildings make characterful, durable homes. Alongside them sit Cornwall's many redundant chapels, which convert into some of the most striking homes in the county.
Granite and cob behave very differently to brick, and Cornwall's damp, mild climate is unforgiving of trapped moisture. These buildings need breathable construction and a real understanding of how thick masonry and timber work together — exactly the kind of work we specialise in.
A barn conversion lives or dies on the carpentry. We carry out the full structural and joinery package: repairing or replacing failed purlins, rafters and wall plates; introducing new floors and internal framing inside an open shell or chapel; forming roof structures that take modern insulation while keeping the original roofline; and the finishing joinery — doors, windows, staircases and flooring — that turns a shell into a home.
For new framing we work in green oak, using traditional mortice-and-tenon joints and pegs. In Cornwall's damp climate we pay particular attention to keeping timber clear of damp granite and cob, using lime-friendly, breathable build-ups and durable, treated structural timbers so the converted building stays dry and healthy.
The planning route shapes the whole project, and in this area every determination is made by Cornwall Council as the unitary authority. Many agricultural barns can be converted under Class Q permitted development without full planning permission, subject to prior approval and strict conditions on size, structure and location. Listed granite barns, chapels and buildings within conservation areas fall outside Class Q and need full planning and listed building consent.
Cornwall Council also applies its own local design guidance to protect the character of Cornish buildings, so the choice of materials and detailing matters from the outset. We build to whatever consent has been granted and work hand-in-hand with your planning consultant and architect.
Barn conversions are major projects, and the carpentry is generally priced per square metre of floor area. The figures below are a 2026 guide for the carpentry and structural elements of a mid-Cornwall conversion.
| Scope | Guide price | Notes |
|---|---|---|
| Sound granite barn, finishing joinery led | £800 – £1,000/m² | Minimal structural repair needed |
| Moderate structural & roof work | £1,000 – £1,300/m² | New framing, partial re-roof |
| Listed barn / chapel / oak framing | £1,300 – £1,500/m² | New trusses, full re-roof, exposed oak |
These figures cover the carpentry and structural elements only; whole-project costs including all trades, services and fit-out will be higher and are best estimated once your design and consent are settled.
Barn conversions are unforgiving — rural sites, unpredictable old structures, a damp climate and demanding planning conditions all in one project. With over 10 years and 200+ projects across Devon and Cornwall, we understand how granite and cob behave, how to keep a converted Cornish barn breathable and dry, and how to work within Cornwall Council's design expectations. We restore original trusses, cut green-oak frames and coordinate the carpentry around the wider build programme.
You get clear, written, itemised quotes, a realistic timeline, and an honest early warning about the things old buildings like to hide.
Many agricultural barns in mid-Cornwall — around Probus, Tresillian and the lanes towards Falmouth and Penryn — can be converted under Class Q permitted development without full planning permission, subject to prior approval from Cornwall Council. Listed granite barns, converted chapels and buildings within conservation areas fall outside Class Q and need full planning and listed building consent.
Cornwall's damp, mild climate and the thick granite and cob walls of its barns demand breathable construction. We avoid trapping moisture by using lime-based detailing, breathable membranes and insulation, and we keep timber clear of damp masonry with proper ventilation and durable, treated structural timbers so the converted barn stays dry and healthy.
Yes. Mid-Cornwall has many redundant Methodist chapels alongside its granite-fronted cottages and agricultural barns, and these make striking conversions. Chapels are often listed and need full planning and listed building consent, with careful structural carpentry to insert floors and a roof structure while keeping the original character.
Barn conversion carpentry around Truro typically runs from £800 to £1,500 per m² in 2026. A sound granite barn near Probus needing mainly finishing joinery sits at the lower end, while a listed building or chapel requiring structural repair, new trusses and a full re-roof sits towards the upper end.
Get a free, no-obligation consultation and quote for your barn or chapel project across Truro and mid-Cornwall.
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