This calculator assumes each wall is rectangular and deducts 3 mm per panel from the physical face width to allow for interlocking cover. Corner pieces are calculated from the number of exposed vertical corner or end runs selected for each wall, with corner colours auto-matched to the selected cladding colour where available. Fixing kits are calculated only for Slimline products, at 100 fixings per kit. For wall runs over 2.9 m, butt joins split boards end-to-end, while cap joins add 2.9 m cladding cap pieces across the join line. Openings, mitres, window trims, top and bottom caps, expansion requirements and detailed site set-out may change the final quantity.