StructuralClaw / Free tools / Snow load

Snow Load Calculator — ASCE 7-22

Flat-roof snow pf, the §7.3.4 minimum pm shown as its own load case, slope factor Cs, and unbalanced gable snow. Every factor cites the table it came from. Runs in your browser; nothing is uploaded.

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Site

From the ASCE 7 Hazard Tool or Figure 7.2-1 for your site.

Ce per Table 7.3-1 — roughness row × exposure column. Above tree line and treeless Alaska have no sheltered column.

Roof

Ct interpolated from the Table 7.3-3 grid on R and pg; R > 50 takes Ct = 1.2 (footnote b). R-30 is a common insulated roof.

The §7.3.4 minimum for low-slope roofs — kept as a SEPARATE load case pm below: a separate uniform case, not additive with drift or unbalanced loads.

Unbalanced (gable) — optional

Both values > 0 run the 7-22 §7.6.1 method (W₂ from Fig. 7.6-1 / the Hazard Tool). Left at 0, the engine falls back to the pre-7-22 simplified 2pf/Ce and says so.

Results

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enter values and press Calculate

How this is calculated

Formula chain with code citations 
Run a calculation to see the chain.

pf = 0.7·Ce·Ct·Is·pg (Eq. 7.3-1) · ps = Cs·pf (§7.4) · pm per §7.3.4. The drift surcharge at parapets and adjacent roofs (§7.7) is a desktop feature — this page flags it, the desktop app computes it.