Stone threshing barn conversion cost
Stone threshing barns scope at £2,180 to £2,640 per square metre at mid spec on our indicative Q2 2026 model. A 200 m² stone barn at mid spec, fair condition, lands at roughly £510,000 to £680,000 all-in before VAT431C reclaim.
The £/m² band
Our indicative band for a stone agricultural-to-residential conversion is £2,180 to £2,640 per m² for mid spec, including labour and materials but excluding professional fees and VAT. It is a scoping model inflated to a Q2 2026 footing via the ONS construction output price index, not a figure from a single published dataset; a chartered QS can price your specific building against RICS BCIS.
Where the spend sits
Structural interventions
A stone threshing barn rarely converts without a steel or timber ring beam to take the new roof load and stabilise the gables. A chartered structural engineer's appraisal is essential for Class Q and prudent for full planning; budget £1,200 to £2,400 for the appraisal alone.
Re-roof choice
Welsh slate is the regional default for the Cotswolds, Yorkshire Dales and North Wales, with cost driven by current supply lead times rather than headline rate. Clay plain tile (Heather or similar) is the South-East default and runs 25% to 40% cheaper. Stone slate is the gold standard for AONB sites and runs £230 to £360/m².