What is an “Ice Dam”?

Given the historic nature of the back-to-back snow storms that have hit this area and the number of homes that have been affected by ice dams, I wanted to provide information I hope is helpful pertaining to ice dams. Ice dams are not covered by warranty and must be submitted to your insurance carrier for claims for interior damage. I have also included a definitive illustration of an ice dam.

If you were one of the thousands of residents who had ice dams, there is virtually nothing that could have been done to prevent them, particularly with the amount of snow that accumulated on your roof. Quite simply, an ice dam is a block of ice that forms at the edge of the roof preventing the melting snow from properly draining off the roof. This melted water backs up behind the ice dam and remains a liquid. The water will find the path of least resistance to escape, and it finds cracks and openings in the exterior roof into the attic through the walls or ceiling.

While code requires that roofing underlayment be installed 24 inches from the eave, it is merely a preventive measure, rather than a guarantee, that water will not back up and find its way into the interior. Interior damage should not be repaired until the ceilings and walls are dry.

I have spoken to several experts in the roofing industry this winter to pass along their views to frustrated members of our community. Because ice dams are not covered by either roofing contractors or manufacturers, you will need to contact your home insurance carrier. I have spoken to several insurance agents, and they have assured me that interior damage caused by an ice dam will be covered. Exterior damage will not be covered because it is considered an act of God and nature.

CertainTeed, one of the leading shingle manufacturers in the country, issued a technical announcement on February 19, 2010, defining ice dams as follows:

“If the snow/ice formation is dense enough (called an “Ice Dam”), the melt water will back up behind it. Since standard shingle roof systems are water-resistant, not waterproof, the accumulated water can leak into the structure through the shingle joints. . . . Note that leaks caused by ice dams are not covered by CertainTeed Asphalt Shingle Limited Warranty . . . . Homeowners who incur losses due to leaks caused by ice dam conditions should contact their insurance carrier.”

I also called the National Roofing Contractors Association (NRCA) in Chicago (an area that is very familiar with ice dams) and spoke to the Senior Director of Technical Services who told me that ice dams are treated as an act of God and nature and not the fault of the manufacturer or the roofing contractor. Damage to the interior should be reported to the customer’s insurance carriers. He said that the recent storms in our area were a freakish situation comparable to floods, high winds and other acts of nature. Because snow acts as insulation and melts during the day and refreezes at night, water cannot escape through normal channels and therefore backs up under the shingles causing interior leaks. This is contrary to the design of roofs where the water is expected to roll off the roof rather than back up –thus there is no way to prevent the formation of ice dams. NRCA also pointed out that even if you had heated eaves, they would not have prevented ice dams considering the amount of snow we had.