Protecting Your Home Against Ice Damming
Ice dams are ridges of ice that form at the edge of a roof and they prevent melting snow from draining off the roof. This can cause water damage.
Melt water backs up behind the ice dam and works its way up and under the roof covering and flows into the attic. It can then seep through insulation, ceilings, walls and other areas where it can cause damage, including structural damage and mold in extreme cases. Ice dams form when interior heat rises through the ceiling. The heat enters into the attic and warms the roof surface. The warming roofing surface melts the snow that is present on the roof. The melt water flows down until it meets the part of the roof that is at freezing temperature. At that point, the water freezes and begins to form an ice damn.
To help prevent ice damming, keeping a consistent attic temperature is critical. Proper ventilation, along with proper installation of insulation help maintain desired attic conditions, as well as roof deck conditions. Upon re-roofing your home, it is also imperative that a proper ice and water barrier underlayment is installed on the roof if you experience ice damming.