Ice dams form when snow melts on a warm upper roof and refreezes at the colder eaves, trapping water that can back up under shingles. Lasting ice dam prevention starts in the attic, with the right roofing and insulation products installed correctly.
Our Michigan building supply team has helped contractors and homeowners protect roofs through harsh winters for more than 130 years.
Here's what you need to know about ice dams and how to stop them.
What Causes Ice Dams?
Ice dams start with . Snow melts over the warm part of the roof, runs down, and refreezes at the colder eaves and gutters.
Warm air leaking up from the living space is usually the culprit. Research cited by the state also shows on attic air temperature.
Why Ice Dams Damage Roofs
Water pooled behind the ice can work its way under shingles and into the roof deck, walls, and ceilings. Icicles hanging along the gutters or eaves can be an early sign that an ice dam is forming.
That is why builders use several layers of protection to prevent roofing leaks at the eaves, valleys, and other weak spots.
Seal Air Leaks Into the Attic
Air sealing comes first, because small gaps around ceiling penetrations and attic hatches let warm indoor air into the attic. The University of Minnesota Extension calls air leakage the major source of the heat behind ice dams in many homes.
Seal those gaps before adding insulation, or the new insulation will not do its full job.
Add the Right Amount of Attic Insulation
ENERGY STAR recommends in climate zones 5 through 7, which cover the state. More insulation keeps heat in the house and off the roof deck.
Eikenhout carries insulation from brands such as Hunter Panels, Owens Corning ProCat, and Atlas. Our guide to attic and crawlspace insulation explains where it matters most.
Keep the Attic Ventilated
Only a small amount of roof ventilation is needed to keep roof surface temperatures even. Building researchers at UMass Amherst call a the most effective setup.
The University of Minnesota Extension does not recommend mechanical attic fans for this purpose.
Install an Ice Barrier at the Eaves
The state residential code calls for an that runs at least 24 inches inside the exterior wall line. It can be a self-adhering membrane or two layers of underlayment cemented together.
An ice barrier stops water that gets past the shingles, but it is a backup layer, not a cure for attic heat loss.
Clear Snow Safely From the Ground
A roof rake used from the ground can pull heavy snow off the lower roof before it melts and refreezes. Rake gently and leave a thin layer, since a rake can scrape shingles.
Our tips on how to use a snow rake cover the basics, including why you should stay off the roof in winter.
Frequently Asked Questions
Does homeowners insurance cover ice dam damage?
It depends on your policy, but dwelling coverage may pay to repair ice dam damage that was sudden and accidental. Insurers typically will not pay to remove the ice dam itself.
Damage tied to poor maintenance likely will not be covered either. Review your own policy with your agent before winter so there are no surprises after a heavy snow.
Should you chip ice dams off the roof?
No, chipping or hammering at an ice dam usually does more harm than good to the roof and to the person doing it. Building researchers at UMass Amherst warn against it.
For a temporary fix, the University of Minnesota Extension suggests melting a channel through the dam with tap water on a warm day, though the channel stops working within days.
Do heat cables prevent ice dams?
Heat cables can melt a path for water, but they treat the symptom rather than the cause. UMass Amherst building researchers note that the cable can create a new ice dam just above it.
Sealing attic air leaks and adding insulation address the warm attic that causes ice dams in the first place, which is why most experts start there.
Do gutter guards cause ice dams?
No, gutters and gutter guards do not cause ice dams, though full or iced-over gutters can make the damage worse. Keeping gutters and downspouts clear lets meltwater drain away from the roof edge.
Eikenhout has noted that even with guards in place, gutters still need cleaning at least twice a year to clear out small debris.
Where can contractors pick up roofing and insulation materials?
Eikenhout has 10 branches across the state, including Grand Rapids, Lansing, Holland, Kalamazoo, Muskegon, Saginaw, Mount Pleasant, Traverse City, Petoskey, and Gaylord. Each location is open Monday through Friday from 7 AM to 5 PM.
Our headquarters is still at the original Grand Rapids location, where Hendrick Eikenhout opened his roofing supply company in 1894.
Request a Roofing Quote
Stopping ice dams takes the right mix of air sealing, insulation, ventilation, and underlayment. Our team stocks shingles from GAF, Owens Corning, CertainTeed, and Malarkey, along with the insulation and underlayments that go beneath them.
Stop by any branch of your Michigan building materials supplier for a quote on your next roof, find the nearest branch, or send us a message online.
