Looks can be deceiving. For instance, there are few things as lovely as icicles hanging from roof eaves and gutters. In some regions, they dangle for months, like crystal jewels, sparkling in the sunshine. And yet, in many cases, they signal that the roof may have a problem with ice dams that needs attention before water seeps into the house.
Ice dams — literal dams made of ice — usually form at eaves and gutters and prevent snow- and ice-melt from leaving the roof. They’re often caused by a temperature imbalance in the attic. As heat rises in the house and makes its way into the attic, the upper portion of the roof may warm faster than the lower portion at the eaves. If the upper portion becomes warm enough to melt snow (above 32°F) while the lower portion remains below 32°F, snow will melt, flow down the roof, and refreeze before it can flow off the edge. This can also be compounded by naturally rising ambient temperatures during the day and falling temperatures at night. What results is a dam, which will hold the remaining water, snow, and ice on the roof.
There are two main causes of this kind of temperature imbalance:
Why are ice dams a problem?
Almost all roofing materials are designed to shed water. As ice melts and refreezes, it can damage the shingles and other parts of the roof system. And when a growing ice dam pushes water back up the roof slope, that water may flow under the shingles and penetrate into the roof system or house below. That’s why GAF factory-certified roofers will always recommend a layer of strong protection like WeatherWatch® or StormGuard® Leak Barrier. These products help prevent leaks due to water backing up in your gutters, wind-driven rain, and, of course, damaging ice dams. They are self-adhering membranes that seal around fasteners and other protrusions in the roof, helping to protect the most vulnerable areas of your roof against leaks.
What can I do about ice dams?
Here are 3 steps you can take to prevent ice damming this summer: