Snow load in Calhoun County, Michigan: pg = 25 psf
The code ground snow load in Calhoun County is 25 psf (1.2 kN/m²) — 69 of 83 counties have a higher value in Michigan. The calculator below is prefilled with that value: choose exposure, thermal condition, risk category and roof slope to get the roof snow load.
| Where | pg (psf) | kN/m² |
|---|---|---|
| All of the county except the jurisdictions below | 25 | 1.20 |
| city of Battle Creek, city of Marshall, city of Springfield, village of Athens, township of Athens, township of Battle Creek, township of Bedford, township of Convis, township of Emmet, township of Lee, township of Leroy, township of Marengo, township of Marshall, township of Newton, township of Pennfield | 30 | 1.44 |
Educational estimate only. Excludes drifts, sliding snow, rain-on-snow surcharge, unbalanced and partial loads, and any local amendments. ASCE 7-22 changed the method (risk-targeted pg, no Is in pf). Design loads must come from the adopted building code and a licensed engineer.
Check the snow load for a real project
Upload the drawings or describe the roof — Planium works out exposure, drifts at parapets and roof steps, and what to confirm with the Calhoun County building official.
From ground snow load to roof snow load
ASCE 7 converts the ground snow load into a flat roof snow load with pf = 0.7 · Ce · Ct · Is · pg. With pg = 25 psf, a typical heated, partially exposed home in suburban terrain gets pf = 0.7 × 1.0 × 1.0 × 1.0 × 25 = 17.5 psf. Roofs sloped below 15° must also be checked against the minimum load of 20 psf. Steep roofs shed snow, so the sloped roof load ps = Cs · pf falls once the slope passes about 30° on a warm roof.
Drifts usually govern the critical members: snow piles up against parapets, at lower roofs next to taller buildings and in valleys, and can reach several times the balanced load locally.