The Causes of Ice Dams & How to Prevent Them

As the trusted insurance consultants for Wisconsin, Minnesota, and the surrounding areas, we continue to assist area policyholders with property insurance claims after winter accidents and severe weather events. One major culprit for winter home damage is ice dams. Many homeowners may have ice dams without even realizing it. So, what are the signs, causes and cures for ice dams? Norcia Insurance Consultants is here to answer just that. 

Ice Dam on Home in Wisconsin

What are Ice Dams? 

While once thought of as a problem with the roofing or ventilation, ice dams are actually caused by the presence of warm, moist air in the attic, combined with snow on the roof and the right weather conditions. Ice dams occur when heat gets into the attic and then melts the underside of the snow on the roof. This melted snow then flows down the roof until it reaches a cold spot like the eaves or soffit and forms a frozen dam where additional snowmelt and ice build up. Then, the ice buildup can back up under the shingles, damaging them and allowing water to leak into the ceilings and walls beneath. 

Primary Cause of Ice Dams

The primary cause of ice dams are attic air leaks. Air leaks can damage insulation and more. Warm, moist air leaking through holes around plumbing vents, electrical wires, chimneys and more lead to reduced performance of your insulation. And, water vapor carried with the escaping warm air from your home may condense, freeze and build up in the insulation causing plaster and paint to crack and peel, leading to rot and other structural damage.

How to (And How Not to) Prevent Them

Removing snow from the roof can eliminate one of the ingredients necessary for the formation of an ice dam. However, it is important to be careful not to damage the roofing materials, yourself or your property. DO NOT install heating cables as they will shorten the life of your roof and cost money to operate. Also don’t remove ice with chippers, chemicals or heat as it can damage the shingles gutters and other components. Adding additional insulation like higher density foam on the top plate of exterior walls can reduce heat transfer to the roof deck. However, insulation alone is insufficient. 

The long-term solution to ice dams is to air seal your attic. Make the ceiling of your home air tight so warm, moist air cannot flow from the house into the attic space.

Ice dams are no joke so it is important to do everything you can to prevent them from damaging your home. If your home is damaged by ice dams, just keep in mind that the experts at Norcia Insurance Consultants are here to help.