Home Inspection Articles

What is an Ice Dam? - Prevention and Advice

Posted by Thea Scrimger on Dec 4, 2012 12:56:00 PM

SeeAProblem?Snow on your driveway is seldom more than a pain in the back. However, snow on your roof can lead to leakage, even if your roof is new. The culprit is ice damming, the insidious snow-melting phenomenon that many of us are well-acquainted with. Since ice damming is climate driven, warm weather can make many believe that come summer, their problem is solved -- think again. Without a permanent solution ice dams will continue to form on your roof when it gets cold enough. If your roof experienced ice damming last winter, now is an opportune time to guard yourself against this issue and the damage it causes. As winter fast approaches, we encourage homeowners to re-familiarize themselves with ice damming to help better protect their roofs and their homes.

What is Ice Damming?

Heat escapes from improperly sealed or poorly insulated portions of the roof, melting the snow above. As the snow melts, it runs down the roof until it encounters unmelted snow over an unheated space on the roof. There, it will stop and refreeze. This process will continue until an ice dam is formed.

Why is Ice Damming Problematic?

These dams cause the water that runs down the warm portion of the roof to pool behind the dam and back up under the shingles. Once the water from the ice dam gets under the shingles it is free to leak into the ceiling and the wall. While it is periodic, (eventually the weather will warm up, thus stopping the leak), this water intrusion can become costly. If left uncorrected, water damage will occur to at least the ceiling or wall finishes, and at worst, there is a potential for structural rot.

How can Ice Damming be Prevented?

There are two major preventative measures to consider when approaching the issue of ice damming.

1. Adding attic insulation: This will work well depending on the attic in question. However, some attics have so many warm air leaks that it would be impossible to add enough insulation to fix the problem.

2. Sealing the air leakage paths into the attic space: In many cases, with proper sealing tools a homeowner can take care of this task themselves. However, some instances require a specialist to find and fix the issue. Common air leakage paths include attic access hatches, ceiling light fixtures like pot lights, and plumbing stacks.

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Topics: Home Reference Book, Homeowners, Home Inspection, Carson Dunlop, Homeowner Tips