Per-square-metre rates work reasonably well for vanilla new build because the scope is narrow and repeatable. For refurbishments — especially in Devon’s older housing stock — the variance is enormous. A 90 m² barn that needs structural strengthening, new drainage and conservation-grade joinery is not the same job as a 90 m² 1970s extension.

For investors and landlords we use low-level take-offs at feasibility stage rather than rates. It takes longer, but it produces numbers you can hold a project to. The alternative — buying a property on a per-m² assumption that proves optimistic — is the most expensive shortcut in the business.

Use rate-based estimates for shortlisting opportunities. Use a take-off when you’re ready to commit.