SnowLoadCheck

Mercer County, OH Roof Snow Load - 20 psf

Mercer County, OH: your roof's ASCE 7 snow number, in plain English

Moderate
20 psf

Mercer County's roofs are built to hold 20 psf of snow, the ASCE 7-22 figure a permit reviewer checks first. §7.3.4's low-slope minimum of 20 psf is what actually governs on a flat or low-pitch roof here - higher than the 14 psf the base ground-load formula gives.

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.

Mercer County, OH: quick facts

Mercer County by the numbers

Nationally that's #770 out of 2,758 rated counties, the top 28%; within Ohio alone, Mercer County ranks #55 of 86. Mercer County's figure lands almost exactly on Ohio's own county-average of 20 psf.

Mercer County, FIPS 39107, is home to 42,648 people near 40.5353°N 84.6321°W. Its 20 psf ground snow load figure is the map value; 20 psf is what a roof is actually designed for.

Mercer County's snowfall, most winters

10.4 in. a year: that's Mercer County's NOAA 1991-2020 snowfall normal, measured at ST MARYS 3 W, OH US (10.2 mi away). See the density guide.

Before you rely on Mercer County's number

Treat the Mercer 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. (How this figure is calculated.)