Ice damming is a phenomenon that often occurs during the winter in cold, snowy regions. As snow melts along the roof of a home or building, it may refreeze along the eaves of the roof to form a ridge of ice. This ridge of ice traps the remaining snow as it melts, leaving an area of standing water on the roof that may seep through any openings. If it enters the roof, this standing water can lead to problems such as rot or mold. Icicles along the edge of a roof are a good sign of an ice damming problem.
A number of factors can contribute to ice damming, including home design. Houses with a sloped roof are most likely to suffer from this occurrence. Other factors, such as lack of insulation or unsealed areas in the attic floor can also contribute to ice damming. Any combination of issues that results in a warm roof with cooler edges can cause ice damming to occur.
Once ice dams have formed along a roof, homeowners should take immediate action to prevent damage to the home. It's helpful to start by cleaning the gutters, if possible, to give new snow and melted ice a place to go. Next, homeowners should use a roof rake or large push broom to push all remaining snow off the roof very carefully. Finally, the ice dam itself should be chipped away or melted using hot water or a specialty roof heating system.
While some believe that removing the gutters from the edge of the roof will prevent ice damming, this is generally not recommended. While gutter removal may reduce ice damming, it can lead to greater problems in the spring. As temperatures warm up, melted snow and ice will seep down the walls of the home and cause damage to the structure, including the foundation. Roof heat tape along the eaves and gutters offers a better solution to this problem.
To eliminate the causes of ice damming, homeowners should work on properly sealing and insulating the attic. Seal any openings in the attic floor to keep hot air from passing from the home to the attic. Add additional insulation to the entire attic, but remove any insulation that's blocking exhaust or air intake vents. Finally, add additional ventilation to ensure adequate air flow in the attic. These steps will prevent hot spots along higher portions of the roof, which are one of the primary causes of ice damming.