The Facts About Ice Dams

Dec 10, 2020 | Roofing, Spouting


An ice dam is a ridge of ice that forms at the edge of a roof and prevents melting snow from draining off the roof. The dam is formed when snow and ice freeze into one solid chunk of ice in the gutter. Heat loss from the house starts to melt the snow and ice above the ice dam. The melted ice cannot get off the roof because of the ice dam. The water then can back up under the shingles and leak into the house causing damage to ceilings, walls and floors.

How common are ice dams in the winter?

Ice dams can occur when the conditions are right. There are three factors that contribute to ice dams: snow, guttering and long-term cold. When we have significant snow, it can build up in the gutters and if the temperature stays cold long enough the snow will become hard packed ice.

What to do should an ice dam occur?

The first solution, if possible, is to get the snow off the roof. This is dangerous and it is not recommended that homeowners get on the roof to remove snow. Secondly, the ice dam must be removed. Do not chop away at the ice. Ice melt products, like what is used on sidewalks or driveways, can be put into a woman’s stocking. The stocking can then be put on top of the ice dam to help with the melting process.

How can ice dams be prevented?

There are three steps to help prevent ice dams. First, install ice and water shield at the edge of the roof during new roof installation. The material must extend past the exterior wall of the house at least 24”. The ice and snow product is a waterproofing material that seals permanently to the roof deck. When the nails are driven through the ice and water shield the nails are then sealed by the material to prevent water from coming through the nail holes.

Secondly, adequate insulation is a must. Lack of proper insulation causes heat loss. Heat rises and causes the snow to melt. The snow melts and because there is an ice dam at the gutter area that water backs up and into the house.

Thirdly, proper attic ventilation proves to be important. Without the right ventilation, the warm, moist air that escapes from the living areas below can heat the attic. Thus causing the snow to melt and back up under the shingles. Good attic ventilation will keep the air moving and minimize the snow melting on the roof.

The bottom line when it comes to ice dams.

Having a good roof installed with ice and snow shield at the eaves, proper ventilation and proper insulation go a long way in preventing ice dams. Quick removal of snow is always a plus but also very difficult to do.

To make sure your home is prepared for the cold, winter months, contact Greenawalt Roofing Company today!

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