Thinking About Costs: A Realistic Guide to Planning Your Build in Devon in 2026
Whether you are embarking on an ambitious new build, planning an extension, or simply looking to make your current home function better for your lifestyle, the most pressing question is almost always: how much is my eco-house / Passivhaus build going to cost in Devon?
At Folia Architects, we prioritise open and realistic conversations from the very beginning so you can plan with complete confidence. We are often asked:
How much does an eco-house cost to build in Devon?
How much does a Passivhaus cost to build near Exeter?
How much does an eco barn conversion cost in the South West?
What Affects the Cost of a Project?
In our experience as bespoke home architects in Devon, no two budgets are ever the same. However, the variables usually fall into four main categories:
Logistics and Topography: The physical nature of your site plays a massive role; for instance, steep slopes, limited vehicle access (common in narrow Devon lanes), or challenging ground conditions like rock or clay can significantly increase construction complexity and expense.
The Value of Efficient Design: It is a common misconception that a larger footprint equals a better home. We often find that a smaller, more intelligently designed extension delivers far more impact and value than a larger, unconsidered space.
Specification and Craftsmanship: Choosing bespoke architectural features, such as cantilevers or glazed corners, requires specialist labour and higher investment. We love incorporating high-performance, sustainable materials into our designs and always work to balance these premium choices with your overall financial goals.
Managing the Unknown: When breathing new life into older properties in the South-West, "retrofit surprises" are almost inevitable. From hidden structural damp to outdated wiring, these issues can appear once the build begins, making a healthy contingency fund an absolute necessity for any home renovation.
Ballpark Figures for Your Build
Every project is unique, but the following figures provide a rough guide for build costs per square metre:
· New Builds: Approximately £2,500 – £4,000 per m², depending on the level of finish and sustainability.
· Passivhaus: Approximately £3,500 – £4,500 per m², depending on the level of finish and sustainability.
· Extensions: Usually between £3,000 – £5,000 per m². This may increase for properties with restricted access or complex groundworks.
· Barn Conversions: Around £3,000 per m², depending on the level of finish and sustainability.
· Retrofit and Refurbishments: Typically from £1,500 – £2,000 per m², depending on the building's current condition and the scope of work.
Please note: These figures cover build costs only. They do not include VAT (we can put you in touch with VAT experts), professional fees (architectural, structural engineering, etc.), planning submissions, or landscaping. It’s also worth allowing a contingency in your budgeting (we can advise on a sensible project specific amount).
How Folia Architects Protects Your Investment
During the early stages, we work closely with you to shape a brief and a budget that feel realistic. We provide high-level cost ranges and, where necessary, collaborate with cost consultants, such as estimators and quantity surveyors, to ensure accuracy.
We have a track record of saving clients by early project considerations and clear dialogue.
Throughout the design process, we create an open dialogue about cost risks and options.
We believe good design should be grounded in reality. By making smart choices early on, we ensure your budget works as hard as your building does.
Are you looking for bespoke home architects in Devon to help bring your vision to life? We’d love to hear about your ideas and help you navigate the journey from initial sketches to a finished home.
