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Ice dams: What they are, how to prevent them, and what it costs to remove them

Large icicles and an ice dam form on the roofline of a home as more snow continues to fall Friday, March 1, 2019, in St. Cloud.

ST. CLOUD — Ice dams got you down this winter? 

As Central Minnesota continues the long, slow slog towards spring, trudging through a record-setting snow-packed February, many homes are experiencing exterior ice dams that can cause interior damage. 

According to the Minnesota Department of Commerce, ice dams are formed when warm air in a home's attic melts the underside of the snow on the roof.

The melted snow flows down the roof until it reaches a cold spot where it forms a frozen dam, behind which more snow and ice pile up and eventually begin seeping water into the home.

Shane Zablocki, owner of Zablocki Roofing in St. Cloud, said when it comes to the quantity and severity of ice dams, this winter has been like none other in his experience

"In the 20 years of my business, this is the worst I've ever seen it," Zablocki said.

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Zablocki and his crews use hot steam to remove ice dams, which "can be very dangerous work" as it requires standing on icy rooftops.

A roofer shovels snow off a roof to clear an ice dam in the Dorchester neighborhood of Boston, February 2015.

It's why he recommends leaving ice dam removal to the professionals — though he also recommends taking steps to prevent the formation of ice dams in the first place. 

"The whole, ultimate key to prevent ice dams from growing any more is to get the snow off the roof," he said. "Get it off your roof, and not just the bottom four to five feet. That works on some houses, but not all." 

If saving your home from potential water damage isn't enough to motivate you to get the snow off your roof, consider the cost of a professional ice dam removal as compared to snow removal. 

Ice dam removal will cost about $400-500 per hour, according to Zablocki. He said that, so far this winter, most jobs have taken between one-and-a-half to four hours — meaning one session of ice dam removal could cost you upwards of $2,000. 

And if you have an especially significant dam, or own a commercial property with a lot of roof to service, you could be looking at a full-day removal (and a full day's worth of charges.) 


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Snow removal, on the other hand, costs about $250-350 per hour, according to Zablocki, or about half as much as removing an ice dam would cost.

Oh, and snow removal can also prevent other weather-related calamities, like your roof caving in due to the sheer weight of all that dam(n) snow. 

Again, snow and ice dam removal is a dangerous task, one that is best left to professionals. But in the meantime, the Department of Commerce does have a few suggestions on what not to do if you find yourself the unhappy owner of a brand new ice dam: 

  • Do not install heating cables. They can shorten the life of your roof and needlessly add to your energy costs. 
  • Do not remove ice with chippers, chemicals or heat. These can damage shingles, gutters and other building components, and could also lead to personal injury.
  • Do not add roof vents. This includes powered vents. They will not eliminate ice dams, and often make the problem worse, as they provide more areas where water can seep into the home. 

While there's no prevention method that will protect your home from ice dams 100 percent of the time, taking long-term action, like making your ceilings airtight and increasing ceiling and roof insulation, can go a long way for making your future winters easier. 
