Norfolk County, MA Roof Snow Load - 28 psf
Norfolk County, MA: your roof's ASCE 7 snow number, in plain English
Norfolk County's roofs are built to hold 28 psf of snow, the ASCE 7-22 figure a permit reviewer checks first.
In depth, not weight: that's roughly 61.6 inches of fresh, light snow, 22.4 inches of old, settled snow, or as little as 5.6 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. 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.
Norfolk County, MA: quick facts
- Design roof snow load28 psf
- Ground snow load, ASCE 7 map40 psf
- National rank#220 of 2,758
- Massachusetts rank#7 of 14
- Population740,754
- Annual snowfall, NOAA normal56.1 in.
- FIPS25021
Norfolk County by the numbers
Nationally that's #220 out of 2,758 rated counties, the top 8%; within Massachusetts alone, Norfolk County ranks #7 of 14. That's 0.4 psf above Massachusetts's own county-average design load of 27.6 psf.
Norfolk County, FIPS 25021, is home to 740,754 people near 42.1717°N 71.1811°W. Its 40 psf ground snow load figure is the map value; 28 psf is what a roof is actually designed for.
Norfolk County's snowfall, most winters
56.1 in. a year: that's Norfolk County's NOAA 1991-2020 snowfall normal, measured at WALPOLE 2, MA US (3.4 mi away). See the density guide.
Before you rely on Norfolk County's number
Treat the Norfolk 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.