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Accounting for Ice Dams When Underwriting Property Insurance Policies


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Ice dams by the numbers

Accounting for Ice Dams When Underwriting Property Insurance Policies

February 10, 2020

Ice dams are a common threat in northern states during the colder months, and they can result in sizeable property damage claims. Homeowners and building maintenance crews continue to be the front line against this threat. However, insurance professionals should also be knowledgeable in this area so that agents can provide informed coverage advice, underwriters can accurately assess risk, and adjusters can accurately evaluate claims.

What Are Ice Dams?

As the name implies, ice dams are literal dams made of ice that form on the roofs of buildings. They typically form in the winter when heavy snowfall is followed by a prolonged period of below-freezing temperatures.

The formation of an ice dam begins when dense snowfall accumulates on a building’s roof. The warm roof melts the bottommost snow, which then flows down the roof. As the melted snow reaches a cooler portion of the roof, such as an overhang or even a section that’s above a less heated room, the water refreezes into ice. This ice then creates a dam that blocks the flow of more melted snow, and the process repeats itself.

Within a relatively short time, an ice dam can grow substantially in size and block a large volume of melted snow. Without a way to flow off the roof, additional snowmelt may seep under shingles or through crevices and into a home. Once the water finds its way indoors, of course, it can cause major damage.

How Much Damage Do Ice Dams Cause?

Because of when and where they form, ice dams can wreak havoc before they’re even noticed. They aren’t readily apparent outdoors because the heavy snowfall covers the dam, and they are often not obvious indoors because the initial damage occurs along the roofline. By the time a property owner notices a stained ceiling or peeling wallpaper, the property has already likely sustained significant damage.

Ice dam that formed on a roof

According to data analytics provider Verisk, the average settlement amount following an ice dam claim is around $8,000. This includes only the interior damage to properties, and not any exterior damage that the dams might also have caused.

What Should Property Owners Do When They Notice an Ice Dam?

For buildings that develop ice dams, there are a couple of ways to temporarily mitigate potential damage. With both methods, the primary goal is to reduce snowmelt and allow melted water to flow off a roof.

First, property owners can use a snow rake to pull snow down off of the roof. Even if owners can only reach the edge of their roof, this removes snow from where an ice dam is most likely to develop. Without snow on an overhang, the chance of a dam is reduced — and one that does form will be more immediately visible from the outside. (Any owners who try to get up on a roof to rake snow off higher roofs must exercise great caution to prevent personal injury.)

Ice dam snow removal

Ice Dam Snow Removal

Second, property owners can also use calcium chloride ice melter to melt through existing ice dams. Products with this melt are available through retailers, but one of the most effective ways to use calcium chloride is to fill a spare pair of pantyhose with the salt. 

The salt-filled pantyhose can be (carefully) set in place across an existing ice dam so that the edge of the pantyhose is in the gutter or slightly overhangs the roof. The salt melts a channel through the ice dam, and then any additional snowmelt flows through this channel rather than under shingles.

How Can Property Owners Prevent Ice Dams?

Long-term solutions that prevent ice dams require changes to a building's roof and/or attic space. 

One of the most effective strategies is to improve a roof’s insulation. With better insulation, less heat escapes from a building and its roof remains cooler. This reduces snowmelt on cold days, which in turn reduces the risk of ice dams, since melting snow is the first step in their formation.

Energy Star Recommended Attic Insulation mapEnergy star attic insulation recommendations

Energy Star Attic Insulation Recommendations

As another preventive measure, property owners might also improve ventilation in the attic spaces immediately below their roof. Increased ventilation lessens moisture buildup within an attic and around a roof, which also helps keep the roof surface cool and dry.

The main goal is to keep the roof temperature as close as possible to the outside temperature.

How Can Insurers Account for Ice Dams?

Along with educating property owners about the risks of ice dams, insurers who underwrite policies for cold climates must account for potential claims from this risk. 

If you are underwriting a policy for a property in a region prone to ice dams, make sure to order a JMI QuickVUE report that includes an Ice Dam Score from HazardHub. This measurement combines the severity and duration of below-freezing weather with the amount and duration of snow cover to score insured properties on their ice dam potential. Armed with this information, you can accurately account for the potential financial risk that this peril presents when underwriting a policy.

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