Logan County, IL Roof Snow Load - 20 psf
How much snow is too much for a roof in Logan County, IL?
20 psf: that's what ASCE 7-22 requires a typical heated home's roof in Logan County to carry. Flat and low-pitch roofs in Logan County are actually governed by ASCE 7's §7.3.4 minimum of 20 psf, not the 14 psf the ground-load formula alone would produce.
Picture it, not just weigh it: 44 in. if it's fresh powder, 16 in. once it settles, or a mere 4 in. if it's ice. Modern-code homes carry a load like this without issue; an older addition, a carport, or any flat-roofed section is where it is worth checking first.
Logan County, IL: quick facts
- Design roof snow load20 psf
- Ground snow load, ASCE 7 map20 psf
- National rank#887 of 2,758
- Illinois rank#46 of 102
- Population27,518
- Annual snowfall, NOAA normal19.3 in.
- FIPS17107
How Logan County compares
20 psf ranks #887 of 2,758 US counties with a mapped snow load (top 32%) - and #46 of 102 in Illinois. 19.3 psf is Illinois's typical county figure - Logan County beats it by 0.7 psf.
Population 27,518 (FIPS 17107), roughly 40.1293°N 89.3653°W. The 20 psf ground snow load ASCE 7-22 maps here becomes 20 psf once the code's own design factors are applied.
Typical snowfall in Logan County, IL
NOAA's 30-year normal for Logan County: 19.3 in. of snow a year, from the LINCOLN, IL US station. (fresh vs. packed vs. ice explains why.)
What this Logan County figure assumes
This is a county-level reference figure for a typical heated home built to Risk Category II (ordinary residential), on a partially exposed lot - the assumptions ASCE 7-22 itself treats as the default case. A steeper roof, a fully exposed hilltop lot, an unheated structure, or a higher risk category all change the actual number.
Logan County's permit office wants an address-specific figure, not this county average - the ASCE 7 Hazard Tool is free, takes under a minute, and outputs a PDF most reviewers accept. (How this figure is calculated.)