Wayne County, MI Roof Snow Load - 20 psf
How much snow is too much for a roof in Wayne County, MI?
20 psf: that's what ASCE 7-22 requires a typical heated home's roof in Wayne County to carry. 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.
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. A meaningful design load. Most homes built to modern code handle it, but additions, carports, and flat-roofed sections are worth a second look.
Wayne County, MI: quick facts
- Design roof snow load20 psf
- Ground snow load, ASCE 7 map20 psf
- National rank#499 of 2,758
- Michigan rank#56 of 70
- Population1,771,063
- Annual snowfall, NOAA normal30.8 in.
- FIPS26163
How Wayne County compares
20 psf ranks #499 of 2,758 US counties with a mapped snow load (top 18%) - and #56 of 70 in Michigan. Michigan counties average 31.7 psf; Wayne County runs 11.7 psf lower than that.
Population 1,771,063 (FIPS 26163), roughly 42.2847°N 83.262°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 Wayne County, MI
NOAA's 30-year normal for Wayne County: 30.8 in. of snow a year, from the DEARBORN, MI US station. (fresh vs. packed vs. ice explains why.)
What this Wayne 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.
Wayne 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. See the methodology guide.