Ice Dams in Minnesota: Causes, Prevention and Repair
Ice dams form when heat escaping from your house melts snow on the upper roof, and the water refreezes at the colder eaves.
By Bischel Building, a family-owned general contractor in Farmington, MN. Updated October 2026.
The lasting fix is to stop the heat loss: seal air leaks into the attic first, then add insulation. Roof rakes and channels through the ice help in an emergency, but they don't solve the cause.
If you've lived in Minnesota for a few winters, you've probably seen icicles hanging from a neighbor's gutters and the ridge of ice behind them. Here's what's going on and what actually works, based on guidance from the University of Minnesota Extension and the Minnesota Department of Commerce.
What causes ice dams
According to University of Minnesota Extension, ice dams need three things at the same time: snow on the roof, upper parts of the roof surface above 32°F, and lower parts below 32°F. Snow on the warm part of the roof melts, the water runs down to the cold edge and freezes, and the ridge of ice grows as more meltwater arrives. Water then pools behind the dam, finds gaps in the shingles, and leaks into the attic, walls and ceilings.
The warm upper roof is usually caused by heat leaking from the house into the attic. The Minnesota Department of Commerce points to air leaks around wires, plumbing vents, light fixtures, chimneys and knee walls, along with thin insulation near the eaves, as common culprits.
Signs you have an ice dam problem
- A thick ridge of ice along the eaves and large icicles hanging from gutters
- Water stains or peeling paint on ceilings or exterior walls, often near the corners of rooms
- Damp or frosty insulation, or frost on nails in the attic
- Gutters pulling away from the house under the weight of ice
What to do right now if water is coming in
Extension describes a few short-term steps:
- Remove snow from the roof with a roof rake from the ground, being aware that rakes and brooms can damage roofing materials.
- Make a channel through the dam in an emergency so water behind it can drain, for example by hosing with tap water on a warm day, working upward from the lower edge. Channels stop working within days, so this is only temporary.
The Department of Commerce warns against chipping at ice or using chemicals or heat, which can damage shingles and gutters. If ice has to be removed, it recommends hiring a professional ice dam removal company that uses steam. Please don't climb onto an icy roof yourself.
How to prevent ice dams for good
The long-term fix is controlling heat loss, in this order:
- Air seal the ceiling. Extension's first recommendation is to make the ceiling airtight so no warm, moist air flows from the house into the attic. Commerce recommends sealing attic air leaks with caulk or expanding spray foam.
- Add insulation. After air sealing, add ceiling or roof insulation. Commerce recommends a minimum of R-50 in the attic, as space allows.
- Keep natural ventilation working. Extension notes that natural roof ventilation helps keep roof temperatures even and dries the attic. Keep soffit vents clear of insulation with baffles.
- Find the leaks. Commerce suggests an energy assessment, which can be arranged through your gas or electric utility, nonprofit energy groups or HVAC professionals. Infrared cameras can pinpoint where heat escapes.
What not to do
- Heat cables: Commerce advises against them, saying they shorten roof life and cost money to run.
- Powered attic vents: Extension says mechanical attic ventilation is not a recommended ice dam solution in Minnesota, because it can cause attic moisture problems and negative pressure in the home. Commerce adds that extra roof vents, including powered vents, often make the problem worse.
- Chipping, chemicals or open flame on the ice.
A note on snow load
Once you stop heat loss, snow stays on the roof longer. Extension notes that homes built to current code should handle expected snow loads, and that the plans for your home may be on file at your local building inspection office. If you have concerns about an older roof, a professional engineer can evaluate it.
Repairing ice dam damage
Once the ice is gone, it's time to fix what it damaged and make sure it doesn't happen again. At Bischel Building we repair leaking roofs, replace damaged shingles, flashing and gutters, and repair interior drywall, paint, insulation and flooring. When we replace a roof, we install ice and water protection at the eaves and valleys and look at attic ventilation, so the new roof is set up for Minnesota winters. Ice dam prevention is part of our roofing services. If ice dam damage is from a sudden event, your insurance policy may or may not cover it. Ask your agent, and see our insurance restoration process page for how we work with homeowners and adjusters. For the interior side, see water damage restoration.
Frequently asked questions
Are ice dams covered by homeowners insurance?
It depends on your policy, so ask your insurance company or agent. We can document the damage and give you an itemized repair estimate.
Will a new roof stop ice dams?
Not by itself. A new roof with ice and water protection at the eaves limits leaks, but ice dams are caused by heat escaping into the attic. Air sealing and insulation address the cause.
When should I fix the causes of ice dams?
Attic air sealing and insulation are easiest when the weather is mild, so summer and fall are a good time to plan before the next snow season.
Areas we serve
We repair ice dam damage and replace roofs in Farmington, Lakeville, Apple Valley, Rosemount, Northfield, Burnsville, Eagan and every town on our service area page.
Related services
Dealing with ice dam damage?
Tell us what you have in mind and we'll set up a time to visit. Office hours are Monday to Friday, 8:00 am to 4:30 pm, with weekend appointments by request.