Ice Dam Prevention: Stop Roof Leaks Before They Start

The physics is simple: heat loss from the attic warms the roof deck. Snow above warm areas melts. Meltwater runs down the roof until it reaches the cold eaves (overhang). The water refreezes at the eaves. As the ice ridge grows, it creates a dam. Meltwater pools behind the dam, seeps under shingles, and drips into the attic and interior ceilings. A 6-inch ice dam can hold back 2+ inches of water, causing extensive interior damage.

The permanent cure for ice dams is a cold roof—meaning the roof deck temperature stays at or near outside temperature. Achieve this by: sealing all attic air leaks (can lights, duct boots, plumbing vents, attic hatch), verifying insulation is at R-49 minimum and evenly distributed, installing roof ventilation (soffit intake + ridge vent for continuous airflow), and ensuring insulation baffles maintain 1-inch airflow at the eaves. A thermal imaging camera can identify hotspots that need attention.

For active leaks: (1) Remove snow from the roof edge with a roof rake (first 4 feet). (2) Fill a panty hose with calcium chloride ice melt and place it vertically across the ice dam. (3) The chemical reaction creates a channel for water to drain. (4) For severe dams covering large areas, hire a professional steam removal service. Never use rock salt—it corrodes metal flashing and gutters.