Spray Foam Can Prevent Ice Dams

Ice dams can be a major headache for homeowners during winter months, forming on sloped, or pitched, roofs when snow melts. Often caused by inadequate insulation in the attic space or under the roof, spray foam insulation can function as a comprehensive solution.

When homes lack proper attic insulation, the attic space can become overly warm during winter months. Heat escapes from the living space and also radiates from recessed light fixtures, ductwork, furnaces, and other appliances. The heat in turn raises the temperature of the roof above the freezing point, which melts the snow and ice in contact with the roof surface.

The snow and ice tends to melt in the areas just inside the perimeter of the exterior walls. The meltwater flows downward and refreezes as it passes over the roof overhangs, just above the soffit vents. The resulting ice builds up at the edge of the roof and in the gutters, forming a kind of dam (hence the name). Eventually, the meltwater can flow over the ice buildup and slowly form icicles along the edge of the roof.

During winter months, you will often see some houses with significant amounts of snow on the roof, and others with little to no snow. Counterintuitively, the former group of homes is better insulated than the latter, as the latter group's snow has melted to some degree and formed ice dams.

Damages Can Occur

Ice dams aren't just indications of poor insulation; they can cause serious damage. Melted snow and ice can flow under shingles and soak the roof deck. The water can drip down on ceiling insulation or leak into the areas where the roof connects to the exterior walls. Wet walls and ceilings are potential areas for mold and mildew growth.

Ice dams are also potentially dangerous, as the meltwater can decrease the friction between the unmelted snow and the roof surface, which can lead to snow slides. Also, the meltwater that refreezes as icicles can potentially crack and fall on passersby.