What Are Ice Dams and How Do They Form?
Ice dams (large icicles or blocks of ice along roof eaves) are a common occurrence in the winter and can lead to significant damage to your building if not constructed appropriately. Accumulated snow on a roof acts as insulation. Heat from the underlying space, ambient heat, and solar radiation all contribute to melting the snow. This meltwater runs down the roof towards eaves and gutters. Once it reaches the cold, uninsulated overhangs, it freezes and forms a layer of ice. As this continually happens, the ice height increases, creating a dam that stops drainage. This pooled water backs up and flows under the dry laps in the roofing, resulting in interior leakage and damage. The damage is most severe in areas with frequent freeze-thaw cycles. We offer some tips for quick fixes and long-term solutions to prevent ice dams.
