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What Are Ice Dams?

Ice Dam Diagram from Michigan State University

An ice dam forms when snow accumulates on a roof, then melts and refreezes near the edge. This creates a barrier that prevents water from additional melting snow from draining. It is usually caused by uneven surface temperatures across a roof, such as heat escaping from the interior that slowly melts the snow. Water then runs down to the edge of the roof, where the heat is less intense, allowing the water to freeze again and form a ridge. That ridge is an ice dam.

Ice dams prevent water from flowing off the roof, trapping it instead and backing it up under the shingles and into the attic. This can lead to serious water damage to a home, including mold and mildew issues. Additionally, the weight of ice dams can strain and damage gutters.

Reducing the Risk of Ice Dams

Ice dams can lead to costly damage to roofs and home structures.

It can be extremely difficult to rectify the situation once an ice dam has formed, so it’s best to take action beforehand to protect the roof and house:

  • Clean gutters before snow arrives. Thoroughly clear them of sticks, leaves, and other debris.
  • Use a roof rake to reduce the amount of snow accumulated on the roof.
  • Clear snow and icicles from gutters regularly.
  • Have attic ventilation and insulation inspected.

The surface temperature on a roof is higher if the attic is poorly ventilated or insulated. This, in turn, leads to snow melting and starting the process of forming an ice dam.

Adding ice and water shields during re-roofing can help prevent water from entering the house and mitigate the effects of ice dams. These self-adhesive membranes work as a waterproof barrier beneath the shingles. When ice forces water under them, shields prevent it from reaching the interior and causing damage. To make them more effective, Ellen recommends installing the water shields a few feet from the edge of the roof.

Have questions about ice dams or need a trusted roofing professional? Remember to call Ellen first for expert advice and recommendations! Give Ellen a call at (816) 489-6950 or send her a message online!