Stone vs timber barn conversion cost
Costs verified against BCIS Online (May 2026 release) and ONS Construction Output Price Index, April 2026. Class Q rules current to the 21 May 2025 GPDO amendment.
Stone threshing barns scope at £2,180-£2,640/m² mid spec; timber Dutch barns at £1,650-£2,180/m². The gap is driven by walling, re-roof and structural intervention. Timber wins on cost; stone wins on end-value and character premium.
£/m² compare
Stone threshing (mid spec, BCIS)
£2,180-£2,640 / m²
Timber Dutch (mid spec, BCIS)
£1,650-£2,180 / m²
Where the gap sits
- Walling: stone repointing £60-£110/m²; timber-clad infill £80-£140/m². Stone walls are slower per m² of elevation.
- Re-roof: Welsh slate on stone £170-£240/m²; standing-seam metal on Dutch roof £160-£240/m². Slate is heavier and demands stronger truss.
- Structural: stone needs ring beam and opening formation; timber Dutch needs frame stitching and bracing. Stone is more skilled labour.
End-value compare
Stone barns command a character premium of 12% to 22% over equivalent timber barns at sale, on a like-for-like postcode and spec basis. That offsets a meaningful proportion of the build-cost gap.
Sources cited on this page