Build up a wall, roof or floor from real materials and read the U-value straight off — calculated to BS EN ISO 6946 (and BS EN ISO 13370 for ground floors), checked against Building Regs and Passivhaus targets as you go.
Fabric Bench is a free tool built by Lestrange Carpentry. Figures are calculated from the material properties you enter using standard UK methods — always confirm against your manufacturer's datasheet before relying on a result for Building Regulations compliance or a SAP/PHPP submission.
We design and build Passivhaus-standard fabric across Suffolk and East Anglia — from a single wall build-up to a full new-build envelope.
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