Wabash County, IL Roof Snow Load - 20 psf
Wabash County, IL roof snow load, translated
A typical heated home in Wabash County is designed to carry 20 pounds per square foot of snow on its roof, per ASCE 7-22. The physics-based figure alone would be 14 psf, but ASCE 7's own low-slope minimum (§7.3.4) sets a floor of 20 psf for flat and low-pitch roofs here, which is the number that actually governs.
On a roof that means 44 in. of fresh snow, 16 in. once it packs down, or 4 in. of solid ice - three very different piles for the same load. A meaningful design load. Most homes built to modern code handle it, but additions, carports, and flat-roofed sections are worth a second look.
Wabash County in numbers
- Design roof snow load20 psf
- Ground snow load, ASCE 7 map20 psf
- National rank#1,087 of 2,758
- Illinois rank#78 of 102
- Population10,979
- Annual snowfall, NOAA normal11.8 in.
- FIPS17185
Where Wabash County ranks
#78 of 102 Illinois counties by design load, top 39% of 2,758 nationally - that's Wabash County's spot. Illinois counties average 19.3 psf; Wabash County runs 0.7 psf higher than that.
FIPS 17185, population 10,979, centered near 38.4458°N 87.8392°W. ASCE 7's underlying ground snow load here is 20 psf before the code's exposure and importance factors bring it to the 20 psf design figure above.
Wabash County: average annual snowfall
Wabash County sees about 11.8 in. of snow most winters, per the GRAYVILLE, IL US station's 1991-2020 NOAA normal. See the density guide.
Read this before you use Wabash County's figure
The figure above assumes the case ASCE 7-22 treats as typical: a heated, ordinary-occupancy home on a partially exposed site. Change any of those - exposure, heating, roof pitch, occupancy category - and the real design number moves.
A building permit needs the number at your exact address, not the county average - the free ASCE 7 Hazard Tool returns that from your coordinates in about a minute and produces a PDF a plan reviewer will accept. Details: the calculation guide.