Dealing with ice dams

CAUSES

Ice dams form when rooftops become warm enough to melt snow. The water from the melted snow flows under the snow cover to roofs edge, where the temperature is colder and the water refreezes. As more snow melts, more water flows down and becomes trapped, creating an ice dam.

Although the winter sun can heat a rooftop enough to contribute to the thaw-freeze cycle, the most common cause of ice dams is simply a poorly insulated or poorly ventilated attic, said John E. Vieczorek, owner of Vieczorek Builders in Tunkhannock.

What is causing it is the heat loss through the attic, said Mr. Vieczorek, who has installed roofs for 40 years. If there wasnt heat loss, you wouldnt have that melting and freezing.

Because people often see the resulting icicles forming under their gutters, one of the big misconceptions is that gutters cause ice dams, said Eric Judge, co-owner of Judge Brothers Gutters Inc. in North Abington Twp.

They dont create the problem. They are just there catching the water coming off the roof, he said. The icicles are hanging off the gutter just like they would be hanging off the eave if there was no gutter there.

POTENTIAL DAMAGE

As the ice dam grows, the water flowing down the roof can back up under the shingles and leak into the home. That can lead to a host of issues for the homeowner, according to the International Association of Certified Home Inspectors website:

Rotted roof decking, exterior and interior walls and framing.

Respiratory illnesses, such as allergies and asthma, caused by mold growth.

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Dealing with ice dams