How Do Ice Dams Cause Leaks in Your Roof?

Ice dams cause roof leaks because they prevent or impair the flow of water off of your roof.  Ice dams are called ice dams because they are a ridge or blob of ice behind which water dams up.  Water can’t run down and off your roof, because it runs into the ice dam, which most often forms on your overhang.

It may seem odd that in the wintertime there’s any liquid water on your roof, and not just snow and ice.  Barring a rainstorm, the water gets there usually because your roof is overheated and has melted the snow from underneath.  The cause of the warm roof is an overheated attic (one that’s under-insulated or under-ventilated, or both).  Another leading cause of an overheated roof is air leaks into your attic (aka attic bypasses).

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Ice damming is serious once it causes roof leaks

Once your roof has sprung a leak you need to get the ice dam removed right away.  Otherwise, you risk interior water damage, electrical fires, mold, and damaged belongings.  Discomfort, distress, and expensive repairs are pretty much guaranteed.