StruSheets

How to Calculate Roof Live Load Reduction in StruSheets

Apply the IBC 2006 pitched-roof reduction (R1, R2 and the 0.96 kN/m² basic load) and see when pattern loading is required.

StruTools · 23 Aug 2026 · 3 min read

Use Roof Live Load for the original geometry defaults, or Roof Live Load · Pattern for the pattern-check workbook defaults. Both use the same unlocked cells: width, length, slope, purlin spacing and bay spacing.

Lr = 0.96 × R1 × R2. Pattern loading is required when both the purlin and frame reduced loads fall below 0.96 kN/m².

This article provides general educational information. Project-specific structural design, calculations and drawings should be reviewed by appropriately qualified engineering professionals and checked against applicable project requirements and standards. StruTools does not replace engineering judgement or professional design review.