What is an Ice Dam?

Preventing ice dams as homeowners can be a challenge in the winter. An ice dam is a ridge of ice that forms at the edge of a roof and prevents melting snow from draining off of the roof.

What Causes an Ice Dam?

In order for an ice dam to form, a combination of heat loss from the home, snow cover on the roof and outside temperatures each take part. Warm air leaks from the home, heating the underside of the roof, leading to the melting of snow and pooling of water. As the melting snow flows down the roof, it reaches the edge of the roof that is below freezing, causing the ice dam to form. The ice dam will continue to grow as long as it is fed by the melting snow above. This vicious cycle will cause water to build and seep back up the roof. Eventually, the water finds cracks and openings in the roof and flows into the home, causing damage to walls, ceilings, insulation, and more. The weight of the ice dam can also cause damage to your gutters.

How Do You Prevent an Ice Dam From Forming?

You want to keep the roof and attic as cold as possible to discourage melting. In order to do this, you need to prevent heat loss from the home. Here are a few steps you can take:

• Eliminate air leakage. About one-third of the heat loss from your home comes from air leaking through the ceiling caused by small gaps and cracks in drywall, light fixtures, plumbing pipes, chimneys, and more. This can be fixed by air sealing. By stopping these air leaks, you will greatly reduce the amount of heat escaping your home.
• Increase attic insulation. Check the depth of insulation in your attic, if it is below 8 inches, chances are you need more. We recommend blown-in cellulose insulation. It fills more tightly around rafters, joists, and other obstructions, leaving fewer gaps.
• Add roof and soffit vents. Attic ventilation draws in cold outdoor air and flushes out warmer attic air, cooling the attic and the roof in the process.

Already Have Ice Dams?

Check for signs of water leaking. Check the soffits on the house in the attic and ceilings. If you see signs of water or damage, you need to contact an experienced home contractor immediately.