SnowLoadCheck

Wayne County, IL Roof Snow Load - 20 psf

Wayne County, IL: your roof's ASCE 7 snow number, in plain English

Moderate
20 psf

Wayne County's roofs are built to hold 20 psf of snow, the ASCE 7-22 figure a permit reviewer checks first. 14 psf is what the ground-load formula alone gives; Wayne County's 20 psf low-slope minimum (§7.3.4) beats it, so that figure is the one that governs on flat and low-pitch roofs.

In depth, not weight: that's roughly 44 inches of fresh, light snow, 16 inches of old, settled snow, or as little as 4 inches of solid ice - snow that heavy is rare here but ice from a freeze-thaw cycle adds up far faster than the depth suggests. This is a meaningful design load - most modern-code homes handle it fine, though an addition, a carport or a flat-roofed section can be a weak spot.

Wayne County at a glance

Wayne County by the numbers

Nationally that's #1,009 out of 2,758 rated counties, the top 37%; within Illinois alone, Wayne County ranks #61 of 102. That's 0.7 psf above Illinois's own county-average design load of 19.3 psf.

Wayne County, FIPS 17191, is home to 15,928 people near 38.4319°N 88.4324°W. Its 20 psf ground snow load figure is the map value; 20 psf is what a roof is actually designed for.

Wayne County's snowfall, most winters

11.9 in. a year: that's Wayne County's NOAA 1991-2020 snowfall normal, measured at CISNE 2 S, IL US (5.2 mi away). See the density guide.

Before you rely on Wayne County's number

Treat the Wayne County figure as a starting point, not a final answer: it assumes standard occupancy, a heated structure and a moderately sheltered site, per ASCE 7-22's own defaults. Exposed terrain, an unheated building or a steeper roof all shift the real number.

For a real application, skip the county number and go straight to the ASCE 7 Hazard Tool - enter your coordinates and it returns a site-specific figure a plan reviewer will recognize. See the methodology guide.