Ice Damming- Prevention and Maintenance:
Ice dams are a prevalent and damaging winter roofing problem typically caused by a combination of poor attic or roof ventilation and a warm attic space. This often melts the snow that's accumulated on the roof, and allows water to travel down to the eaves (the part of the roof that hangs out past the walls of the home). Since the eaves are away from the structure and heat of the home, this water refreezes forming ice and icicles. As this builds up an ice dam forms, trapping the melting snow and forming a collection of water that often leaks through the shingles, into the attic, and even into the home.
What to look for:
- Icicles on your building - they aren't a guaranteed sign of an ice dam, but you should definitely check for moisture internally (attic and walls) in that area.
- Snow on the roof - if your roof DOESN'T have snow when other homes do, this is a huge sign that your attic is holding a lot of heat! Thus, melting snow and creating ice dams.
- Moisture - when heavy snow accumulates on your roof, check for water damage on any walls that face the exterior.
Preventing Ice Dams
Proper ventilation, attic insulation, and a tight air barrier between the attic and interior of the home are the most important factors in preventing an ice dam.
Proper ventilation will reduce the amount of warm air in the attic, and could save you money on your heating bill! The best ways to ventilate is through vents in the soffits and the ridge of the home. Vents in these two places will create a natural air flow and a consistent temperature throughout the attic.
12 inches of fiberglass or cellulose (R-38) is recommended for most homes. Good insulation is key to maintaining a cool temperature in the attic space and reduce the amount of heat that escapes from the living space and areas you want to heat. A properly insulated attic will also help save money on heating bills!
Reduce Snow Accumulation -
The longer snow stays in your roof; more likely there will be ice dams. Roof designs with low pitch, valleys and skylights can also contribute to ice damming. Valleys are especially prone to snow packing.
Trying to shovel can be a scary and unsafe task. Homes that have metal roofing can enjoy the smooth surfaces that help the snow shed naturally. When in contact with the sun, the metal will dissipate the heat across the entire roof, shedding snow more evenly, even at the lower parts of the roof, where dams often form. Metal roofing can therefore be less prone to ice damming compared with asphalt or wood shingles.