How Does Ice Damming Cause Roof Leak Damage?

Ice dams start with uneven roof temperatures. The upper part of your roof, warmed by heat escaping from your attic, melts snow. This water runs down until it reaches the colder roof edge or eaves, where it refreezes into a ridge of ice.

This ice ridge acts as a dam. As more snow melts from the warm upper roof, the water pools behind this dam. With nowhere to drain off the roof, the water can then seep backwards under the shingles, finding its way into your home's structure.

Poor attic insulation is a primary cause. When heat from your living space escapes into the attic, it warms the roof from underneath. Inadequate ventilation compounds the problem, as trapped warm air has no way to exit, keeping roof sections artificially warm and melting snow.

Roof design and weather cycles also play a role. Complex roofs with valleys or low slopes are more prone to ice buildup. Areas with cold winters and fluctuating temperatures create the repeated freeze-thaw cycles that build dams gradually.

• Insufficient attic insulation allowing heat loss.
• Inadequate roof or soffit ventilation trapping warm air.
• Complex roof designs with valleys or low slopes.
• Extended periods of snowfall followed by sunny, cold days.
• Clogged gutters that prevent proper drainage.
• Thermal bridging from recessed lights or ductwork in the attic.

Your first priority is safety and stopping the water flow. Do not climb onto an icy roof. From the ground, you can carefully use a roof rake to remove snow from the lower roof edge. Inside, place buckets under active leaks and move valuables out of the way to prevent further damage.

For a permanent fix and to address any water that has entered, contact local water damage pros. They can assess the extent of the moisture and begin drying procedures. You should also consult a roofer to improve attic insulation and ventilation to prevent future dams.