An ice dam is a thick ridge of ice that forms along the edges of roofs when snow melts and refreezes.
Ice dams can wreak havoc on roofs and gutters. Initially, snow accumulates on the roof of a home. Sunlight or heat coming from within the home causes the snow to melt. This can lead to an accumulation of water on the eaves of the roof and within the gutters themselves. Cold winds and lower temperatures at the roof’s edge cause a ridge of ice, also known as an ice dam, to form.
Contrary to popular belief, gutters do not cause ice dams. Damage to gutters often occurs as ice forms on both the perimeter of the roof and within the gutter trough. As the water freezes and expands, the ice can cause cracks in the gutter system. Additionally, the weight of the ice can cause whole sections of the gutter to break loose from the house and fall to the ground.
Damage to roofs occurs as melting snow gathers behind the ice ridge, causing water to seep beneath the shingles and underlayment. Significant water damage creates loosened shingles and water leaks within the home, which can cause sagging ceilings, stained walls, ruined insulation, and mold.
How to Prevent Ice Dams
Ice dams are simply a fact of life in regions where cold temperatures and snow are common. Prevention is key to limiting the potential damage of ice formation on a home. Fortunately, there are many ways to address this problem.
Keep Attics Cold
To prevent snow from melting and forming an ice ridge, you need to keep attics cold. The addition of thick insulation to the floor of accessible attic space and the construction of roof and soffit vents can allow warm air to escape, reducing heat and prevent snow from melting. Homeowners can further reduce attic temperatures by identifying and patching holes, cracks, and gaps that allow warm air to leak into the attic.
To further prevent ice formation, remove snow from all roof surfaces through shoveling, raking, or other means. However, removing snow from pitched roofs can be dangerous, and must be undertaken with caution.
Heat the Roof
If removing snow and cooling the home’s attic does not curb the formation of ice, heat your roof to prevent ice. Heat cables can be run along the edge of the roof or attached in areas that are prone to icing.
When using heating cables, you must provide an outlet for meltwater, or more ice may form in gutter troughs. Experts suggest running a heating cable inside an adjacent downspout. That way, this allows water to escape the roof without clogging the downspout with icy buildup.