Load Combinations
Which combination governs is rarely the one people assume, and the case that lifts a roof off is not the largest one — it is 0.9D + W going negative. Enter your unfactored loads and every combination is evaluated, with the governing and minimum cases called out.
Uses the basic ASCE 7 combinations. Load factors change between editions and are modified by many jurisdictions; check the code adopted where you are building. Seismic combinations here omit the overstrength and redundancy factors.
PRELIMINARY SIZING ONLY — not a code-compliant design check. These are first-pass equations; they omit member stability, local buckling, shear and combined-stress interaction, connections, second-order effects and jurisdiction-specific factors. Codes vary by country and edition. Structural design must be performed and sealed by a qualified engineer.