How To Stop Ice Dams and Icicles From Forming

November 28, 2011

Have you ever seen thick icicles on the edge of the roof on your home? Or have had water leaking into your attic from your roof after a snowfall? These can be signs of ice dams forming on your roof.

How Ice Dams and Icicles Form

Ice dams and icicles form when warm air escapes the living space of your home

Ice dams typically form when warm air escapes through gaps and cracks from the living space of your home and heat up the under-side of your roof sheathing. As the escaping warm air warms up the sheathing, it melts the snow on top of the roof. As this snow melts, it runs down the roof to the eaves, where the temperature of the sheathing and roof is closer to the outdoor air temperature. As snow melt reaches the cold section of the roof, it freezes, forming an ice dam. As more snow melts, the ice dam becomes thicker and thicker, creating icicles. Meanwhile, water continues to pool behind the ice damn. This pool of water can get under shingles, creating leaks. Icicles are great visual clues that there are ice dams forming on your roof.

How To Prevent Ice Dams and Icicles

Sealing gaps and cracks prevents warm air from escaping your home

The best way to prevent ice dams is to go after the cause of the problem. We know that ice dams are caused by warm air leaking from the living space of your home into the attic. The best solution is to prevent this warm air from escaping by sealing gaps and cracks in your attic. This is typically called Weatherization, or Air Sealing. Using low expansion foam, all gaps, cracks and penetrations in your attic must be sealed, creating an air-tight boundary. Once your attic is properly air sealed, insulation can be added to further help the heat from your home stay inside your home. Insulation levels vary depending on the climate zone your home is located. In New Jersey, BPI recommends an R value between 49 and 60.


Next post: