Ice dams are formed when the sun and heat from the attic melt snow on the upper parts of a roof. Because the ice dam sits over the unheated eaves, it doesn't melt as fast as the snow higher up on the roof. Melt water pools above the dam and, over time, can back up under the roof shingles and seep through the sheathing and into your home. In addition to leaving you with water damage, ice dams can rip off gutters and damage the roof itself.

What to Do Immediately

If you see that water starts to pool on your floors or windowsills or leak from the ceiling, head outside and look at your roof. If you see ridges of ice below piles of snow, an ice dam may be the reason for the leaks. “First you see the dam, then you say it when it happens to your roof,” says Susan Millerick, spokeswoman for the Insurance Institute for Business and Home Safety (IIBHS).

More on Winter Woes

Don’t try to remove the ice dam yourself—few outdoor home repairs are as dangerous as working on a ladder resting against an icy gutter. The solution is to call a professional roofing contractor. “A roofing contractor can remove excess snow from the roof and melt the ice that’s causing the backup,” says Maciek Rupar, technical services director at the National Roofing Contractors Association.

Between 2014 and 2016, there were an estimated 1,600 emergency room visits related to homeowners attempting to remove snow from their roofs.

“To avoid the possibility of a loose ice chunk being freed and falling from the roof onto your head, we strongly recommend that homeowners resist the temptation to climb onto the roof, or use a snow rake to remove the excess snow,” says Don Huber, director of product safety for Consumer Reports.

Removal costs depend on how large and accessible your ice dams are, but most roofers will charge $100 an hour for this kind of hazardous work. You can also call specialists who will spray the dams with low-pressure steam to melt the ice.

“We generally charge $225 an hour, and we can do the average house in 1 to 4 hours, depending on how thick the ice is and how cold the temperature is outside,” says Allan Dou, marketing manager for Hustad Roofing in Hudson, Wis.

And before starting repairs, make sure to check on what coverage is provided by your homeowner's insurance policy. 

Ice dams are typically covered by your homeowners insurance policy," says Scott Semian, assistant vice president of claims for USAA insurance. "This includes damage to the structure caused by a leak as a result of an ice dam. We encourage consumers to check with their insurance professional on their specific coverage and deductibles to make sure they are properly covered.”

If your ceiling or walls have been damaged, don't attempt any repairs until they dry out. You'll also want to address the heat-loss problem that caused the ice dam in the first place. 

What to Do After the Snow Melts

Once the weather warms up, you can take corrective action for next season. “Keep in mind that even if a roofing contractor removes an ice dam over the winter, they’re really only addressing a symptom, not the cause of your problem,” Rupar says.

According to roofing experts, the best way to handle ice dams is to ventilate your attic and insulate between it and the living spaces of the house. This will minimize the temperature differential between the outside air and the air in your attic that causes the dams to form. You may want to consult a weatherization contractor, who can help you locate the areas of greatest heat loss and recommend how to fix them.

Both the Department of Energy and the Consumer Product Safety Commission offer step-by-step instructions for do-it-yourselfers who want to tackle the job themselves. But if your home has a history of ice dams, or if you have ducts or recessed lighting fixtures that extend through the ceiling into the attic, you may want to leave the job to the pros.