02/08/2026
Ice dams are a common winter problem that can quietly lead to serious roof leaks. They form when snow on a roof melts, flows downward, and then refreezes at the colder eaves. This cycle creates a ridge of ice that blocks proper drainage. While the ice itself sits at the edge of the roof, the real trouble starts behind it, where meltwater has nowhere to go.
As water backs up behind an ice dam, it can seep under shingles and roofing materials that are designed to shed water downward, not hold standing water. Once underneath, the moisture can enter the roof deck, insulation, and interior ceilings or walls. The result may be stained drywall, peeling paint, warped wood, or even mold growth—often appearing far from where the ice dam actually sits.
Ice dams are usually caused by heat escaping from the house, which warms the upper roof surface and melts snow unevenly. Poor insulation, inadequate attic ventilation, and clogged gutters all contribute. Preventing ice dams typically involves improving insulation and airflow, sealing air leaks, installing heat cables and safely removing excess roof snow before it has a chance to refreeze.
