Michigan winter roofing, in plain English.

One & Done Metal Roofing · Every figure is linked to a named source

This is the sourced version: official snowfall numbers, how ice dams really form, what Michigan's building code says, and where a metal roof helps and where it doesn't.

01How much snow Michigan really gets

There is no single Michigan snow number. NOAA's 1991–2020 normals put average annual snowfall at 45.0 inches at Detroit Metro Airport, 50.2 at Lansing, 52.1 at Flint, 77.6 at Grand Rapids and 120.1 at Sault Ste. Marie.¹ The snowiest of those gets more than two and a half times what the least snowy does.

How long snow stays matters too. At Lansing the ground carries at least an inch of snow on about 66 days a year; at Sault Ste. Marie it is about 137.¹

Roof design uses a third number. Michigan's residential code assigns a design ground snow load by county, with exceptions for some cities, villages and townships, from about 20 pounds per square foot in parts of southern Michigan to 70–100 in the Upper Peninsula.² That value is the starting point for the engineering, not a measure of how much snow will land on your roof, and your building department can give you the figure for your address.

02What actually causes ice dams

An ice dam forms when the upper roof is warm enough to melt snow while the eave stays cold enough to refreeze it, so the meltwater backs up as a ridge of ice at the edge.³ The warmth can come from several places: heat leaking through thin insulation or air gaps into the roof space, heat sources in the attic, and sun on bare roofing.³

For the roofs that give homeowners trouble, the main source is the house itself. The U.S. Army's Cold Regions Research and Engineering Laboratory concluded that building heat, not the sun, is the primary cause of problem ice dams. In a field comparison near Watertown, New York, two identically built roofs stood side by side: the heated one grew large ice dams and the unheated one grew none.⁴

That makes the fix an attic job: seal the air leaks in the ceiling, add insulation, and keep air moving under the eaves so the roof deck stays cold.⁴ Michigan's 2015 energy code sets minimum ceiling insulation at R-38 in climate zone 5 and R-49 in zones 6 and 7.⁵ ENERGY STAR's retrofit guidance for zones 4C through 8 is R49 for an attic that already has a few inches of insulation and R60 for one with none.⁶

Michigan's building code treats ice as a given. The state's amended design-criteria table marks ice-barrier underlayment as required,⁸ and one municipal handout quoting the residential code describes it as at least two layers of cemented underlayment or a self-adhering membrane, running from the eave to at least 24 inches inside the exterior wall line.⁹ Ask your building department which code edition and section it applies to your address.

03Sliding snow and snow guards

Snow doesn't always stay put on a metal roof. It can bond to the panels and then release in one sheet once the sun warms the surface or meltwater lubricates the bond.¹⁰ That's why the real question isn't whether a roof sheds snow but what is underneath when it does: a door, a walkway, a lower roof.

Snow guards don't cause ice dams, because they don't change the roof's temperature.¹⁰ On standing seam, one metal-roof consultant's paper calls clamps that grip the seam without puncturing the panel the preferred practice.¹⁰ Snow rail on every eave is already part of our published rate, and we flag any spot where sliding snow could land on a door or walkway.

04Two myths worth retiring

"Metal roofs attract lightning." The National Weather Service says metal doesn't attract lightning. Height, pointed shape and isolation decide where it strikes.¹¹

"Hail ruins a metal roof." The Insurance Institute for Business & Home Safety says hail can dent metal roofs but cites no current evidence that dents impair how a metal roof performs.¹² Whether a cosmetic dent is covered is a question for your insurance policy, so read it before you need it.

05What to do about it

• If you get ice dams, have someone look at the attic before the roof. Air sealing, insulation and attic ventilation are the fix; a new roof isn't.
• Ask every roofer you talk to what goes under the roofing at the eaves and valleys, and where the snow will land when it slides.
• Keep gutters clear. The National Weather Service's Grand Rapids office lists it in its ice-dam advice.¹³

Next read: Standing seam vs. exposed fastener →

Also: Where we work →

Sources

1. NOAA NCEI, 1991–2020 U.S. Climate Normals: annual snowfall and days with 1 inch or more of snow on the ground. Stations: Detroit Metro Airport, Lansing Capital City Airport, Flint Bishop Airport, Grand Rapids, Sault Ste. Marie. Each is a single airport station, not a citywide average. NOAA flags both Lansing figures (snowfall and snow-depth days) as provisional, built from 21 and 22 years of data rather than a full 30.
2. Michigan Administrative Code R 408.30515, Table R301.2(5), “Michigan Ground Snow Loads by Jurisdiction,” in the State of Michigan's own rules file (the text in force). Michigan LARA says a July 2025 court order keeps the 2015-based residential code in effect and holds up the 2021-based rewrite. The county figures we cite are the same in both; confirm the current edition for your address.
3. John Straube, Building Science Digest 135, “Ice Dams,” Building Science Corporation, 2006.
4. Tobiasson, Buska & Greatorex, U.S. Army Cold Regions Research and Engineering Laboratory, “Guidelines for Ventilating Attics and Cathedral Ceilings to Avoid Icings at Their Eaves,” ASHRAE Buildings VIII, 2001.
5. Insulation Institute, 2015 Michigan Summary of Key Residential Energy Code Requirements (Pub. N115, April 2025). An industry summary; the same ceiling values appear in the Michigan Administrative Code energy table.
6. ENERGY STAR, insulation R-value recommendations (retrofit table based on the 2021 IECC; climate zones 4C–8).
7. Joseph Lstiburek, Building Science Insight 046, “Dam Ice Dam,” 2011.
8. Michigan Administrative Code R 408.30516 (design-criteria Table R301.2(1)), in the State of Michigan's own rules file.
9. Muskegon Charter Township Building Department, roofing handout (2025), quoting the 2015 Michigan Residential Code.
10. Robert M. Haddock, “The Pitfalls of Snow Retention on Metal Roofing,” ASHRAE Buildings IX, 2004. Haddock is a metal-roof consultant.
11. NOAA National Weather Service, “Lightning Myths.”
12. Insurance Institute for Business & Home Safety, “Natural Weathering and Hazard Exposure.”
13. NWS Grand Rapids, “Roof Ice Dams.”

Written by the One & Done team · Last updated: November 6, 2026