Ice damming is a winter roofing problem where melted snow refreezes at the edge of the roof, creating a “dam” of ice that stops proper drainage.
Here’s how it happens in simple terms:
1. Warm roof → melting snow
Heat from inside the home escapes into the attic or roof deck, warming the shingles and melting the snow on top.
2. Cold eaves → refreezing
As the melted water runs down to the colder edges (the eaves), it refreezes and forms a thick ridge of ice.
3. Water backs up → leaks + damage
Since the water can’t drain off the roof, it backs up under shingles and can cause interior leaks, damaged insulation, sagging gutters, and even mold.
Why it matters?
Ice damming can look minor from the ground but can cause thousands in damage if not handled early.
Prevention basics: