How to Prevent Ice Dams From Damaging Your Home

When snow accumulates on a warm roof, it can wreak havoc inside and out

ice dams along gutters of beige home with blue sky in background Photo: Getty Images

If your shingle roof develops an unexpected leak this winter, ice dams may be the culprit. These ridges of ice can form at the edge of a roof and prevent snowmelt from draining off as it should. Ice dams are often caused by a combination of clogged gutters and an uninsulated attic.

The heat of the sun and any warm air escaping through your roof melt snow on the upper parts of your roof. Because the ice dam sits over the unheated eaves, it doesn’t melt as fast as the snow higher up on the roof. Melted water pools above the dam and, over time, can back up under the roof shingles and seep through the sheathing and into your home. The problem becomes worse with clogged gutters because the melting water has even fewer places to escape. In addition to leaving you with water damage, ice dams can rip off gutters entirely and damage the roof itself.

What to Do Immediately

If you see water starting 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.

More on Winter Woes
CR's Roofing Ratings & Buying Guide
How to Prevent Pipes From Freezing
How to Lower Your Heating Costs This Winter
Products to Help You Weather a Winter Storm

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.

"Climbing onto a slick and snowy roof without proper safety harnesses and precautions, regardless of the reason or conditions, is not a good idea," says James Dickerson, CR’s chief scientific officer. Hundreds of homeowners end up in the emergency room each year after trying to remove ice dams on their own.

Professional removal costs depend on how large and accessible your ice dams are, but Home Advisor estimates the national average cost to remove an ice dam is about $1,200. Angi, formerly Angie’s List, says to expect to pay $300 to $600 per hour for removal, with some roofers requiring a 2-hour minimum.

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

Allstate Insurance notes that dwelling coverage will often cover the costs of repairs associated with ice dams, up to the limits specified in your policy. But personal property coverage may not cover damage to your belongings. In simple terms, insurance may cover repairs to plaster, drywall, flooring, and roofing, but if a leak destroys, say, your collection of rare baseball cards, you’re probably out of luck—make sure to move any valuable personal items out of the way the moment you observe a leak.

If your ceiling or walls have been damaged, don’t attempt any repairs until they dry out, or until you’ve had a chance to speak to your insurance company. When you’re considering any repairs, 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 can cause 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.

The Department of Energy offers 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.

Paul Hope

As a classically trained chef and an enthusiastic DIYer, I've always valued having the best tool for a job—whether the task at hand is dicing onions for mirepoix or hanging drywall. When I'm not writing about home products, I can be found putting them to the test, often with help from my two young children, in the 1860s townhouse I'm restoring in my free time.

More From Consumer Reports