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How to Prevent Ice Dams

By Eastern Insurance, Feb. 21, 2018

How to Prevent Ice Dams

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For homeowners with either older homes or those with improper insulation, ice dams are a common issue that can develop in the winter. Ice dams are formed when water from melting snow freezes on the edge of your roof above the gutter line. Resulting icicles may be beautiful, but they can pose a serious risk to household members and visitors and can result in costly maintenance bills if they are not properly removed before the next thaw. We have prepared this guide to assist you in understanding how ice dams form as well as how to prevent them in the future.

Ice Dam Graphic

How Ice Dams Form

Ice dams are caused by uneven heat loss from your home in wintry conditions, which causes snow to melt and refreeze on the roof. The heat that escapes your home due to poor insulation causes the roof to warm above freezing temperature, which causes snow to melt and then re-freeze at the roof’s edge. If this cycle repeats consistently, an ice dam forms and water collects behind it. As the water pools, it can seep in through even the newest roof and cause expensive water damage.

Preventing Ice Dams from Forming

There are several steps to take to prevent ice dams. The Insurance Institute for Business & Home Safety put together the following list to prevent ice dams before they cause costly damage to your home.

  • Keep your attic well ventilated. According to the Department of Energy, one square foot of free ventilation opening is recommended for every 150 square feet of attic space.
  • Seal air leaks to prevent warm air leakage from plumbing vents, junction boxes from ceiling fixtures and attic hatches.
  • Keep the attic floor well insulated (between 16 and 22 inches of insulation) to minimize the amount of heat rising into the attic from below. The Consumer Product Safety Commission has a great, in-depth guide on how to DIY insulate your home.
  • Remove leaves and other debris from gutters before the first snow. This will help prevent ice buildup in your gutters.
  • Consider installing an ice shield under your shingles the next time your roof is updated.
  • Use a roof rake to clear the snow above the gutter. Clear as much as three to four feet above the gutter to allow water to drain freely into the gutter. Follow these precautions when clearing snow from your roof to prevent injury to yourself and to your roof.
  • Consider hiring an energy specialist to evaluate the performance of your home and recommend “next steps”  to minimize energy waste. Many Massachusetts residents qualify for the Mass Save program, where you will receive a free energy audit along with discounts on any recommended insulation upgrades.
  • Keep your roof cold by:
    • Closing attic bypasses and any air leaks.
    • Measuring attic insulation levels.
    • Adding roof vents to keep your attic and roof cool.

Despite your preparation and prevention efforts, ice dams can still form on your roof. Your home is one of your most valuable possessions,  Make sure it’s properly protected with a thorough review of your home insurance policy. Many of our plans cover damage caused by ice dams in the event of a claim. To learn more, get in touch with one of our personal lines agents by either requesting a quote online, by calling (800) 333-7234 (Option 2), or by emailing us at

Ice Dam CTA
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