How Much Snow Can a Roof Hold in Michigan? Snow Load Limits Explained

Michigan's one- and two-family homes are built under the 2015 Michigan Residential Code. LARA's Bureau of Construction Codes says that while a 2025 court stipulated order remains in place, the 2015 versions adopted by the state remain valid and in effect, so the rules below are the ones that apply as of October 2026.

Rather than leave the snow column blank for each local building department to fill in, Michigan wrote its own answer into the rules. Mich. Admin. Code R 408.30515 amends the code's ground snow load figure and adds Table R301.2(5), Michigan Ground Snow Loads by Jurisdiction. It lists every county with a base value, then names the cities, villages and townships within that county that carry a different number. R 408.30516 then points the ground snow load column of the code's climatic design table to that Michigan table.

Statewide, the values run from 20 pounds per square foot in parts of southeast Michigan to 90 and 100 in the Keweenaw. West Michigan sits in the middle, with a clear rise toward Lake Michigan. The table below lists the counties around Grand Rapids. If your township is named as an exception in the rule, use that number instead of the county base, and confirm it with your building department.

FEMA's guide gives the figures that matter. The weight of one foot of fresh snow ranges from about 3 pounds per square foot for light, dry snow to 21 for wet, heavy snow. One inch of ice weighs a little less than 5 psf, and one foot of ice about 57 psf. Water itself weighs about 5.2 psf for every inch of depth, so slush and ponded meltwater count heavily.

Put those numbers next to the Michigan table and the picture is clearer. A foot of fluffy lake-effect snow at 3 to 5 psf is a small fraction of a 35 psf design load. Two feet of wet, settled snow at the high end of FEMA's range could reach about 42 psf, more than the ground value for most of Kent County, before you count ice at the eaves or a drift behind the chimney. Rain falling into an existing snowpack adds weight without adding depth.

FEMA adds that snow which sits in the sun softens, gets denser and refreezes, and that meltwater can pond and freeze in low spots. So the same snowpack weighs more in late February than it did the week it fell, even if it looks shallower.

FEMA's guide is blunt that an unbalanced snow load, deeper in some spots than others, poses a greater risk to the roof structure than a uniform load. On a house, wind blows snow off the windward slope and drops it on the sheltered side of the ridge, into valleys, against chimneys and dormers, and onto lower roofs beside taller walls. Snow sliding off a steep upper roof lands on porch and sunroom roofs below, adding both weight and an impact force.

Ice dams concentrate load at the eaves, the one part of the roof that hangs out past the walls. FEMA notes that ice dams also stop snow from sliding off, which keeps the load on the roof longer. In West Michigan, where lake-effect snow arrives with a west or northwest wind, the east-facing slopes, valleys and lower roofs are the places to watch.

FEMA's guide opens by saying most buildings are not at risk of snow-induced failure, and that attempting to remove snow from a roof is often more hazardous than beneficial. OSHA's hazard alert on rooftop snow removal says falls cause the most worker deaths and injuries in that work, and that removing snow the wrong way can create an unbalanced load and increase the risk of collapse. OSHA's advice is to remove snow uniformly, avoid piling it on the roof, and clear it from the ground with a snow rake where possible.

On houses, the more common reason to clear snow is leaks rather than collapse: less snow means less meltwater feeding an ice dam. Stellar's own rule of thumb, from its snow removal service, is that it is time when roughly 6 to 8 inches has built up, the two-week forecast holds below 35 degrees, and more snow is on the way. Low-slope porch roofs, flat garage roofs and roofs with a history of sagging deserve earlier attention.