Here is some great info on preventing ice dams on your home from the Insurance Institute of Building and Home Safety.
During freezing weather, heat from your home or business can escape through your roof and melt snow on your roof. The snowmelt can then trickle down to the roof’s edge and refreeze, creating an ice dam that leaves additional snowmelt with no place to go but possibly under your roof. The following IBHS guidance will reduce your risk of ice dams.
- Keep all drains, scuppers, gutters, and downspouts free of debris and vegetation that may restrict proper flow.
- Remove or relocate heat sources that are installed in open attic areas directly under the roof, such as an attic.
- Insulate light fixtures in the ceiling below an unheated attic space.
- If you have penetrations into the attic, such as vents, seal and insulate them so that daylight cannot be seen and airflow is minimal.
- If ice dams form around the drains, connect heating cables to the drains to prevent ice buildup. Heating cables can also be placed on the roof, connecting them to the drainage system so a path is created for the melting ice to follow.