Calculate timber quantities for stud walls, floor joists, ceiling joists and rafters by room dimensions and structural spacing.
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How This Works
Stud count = wall length ÷ spacing + 1 (for end studs), plus noggings at mid-height. Joist count = span length ÷ spacing + 1. All calculations include 10% wastage for cuts. Structural timber typically needs to comply with building regulations — minimum C16 grade for joists, C24 for rafters and heavily loaded members.
Floor joist sizing depends on span and load. Common UK specifications: 47×150mm C16 at 400mm centres for spans up to 3.5m (domestic floor load). 47×175mm for 3.5–4.5m spans. 47×200mm for 4.5–5.5m spans. Always check TRADA span tables or use the NHBC span calculator for your specific load and timber grade. Building regulations require Building Control approval for structural floor changes.