A roof ice dam is an area of ice that forms at the edge of a roof and prevents melting snow from draining off the roof. Water backs up behind the ice dam and can leak into your home and cause a variety of different types of damage to ceilings, walls, insulation, roofing subsystems, and other areas. Many times, the repairs can be significant!
Ice dams form when heat from the inside of your attic warms the roof deck (the boards under your shingles). The heat radiating from your attic in combination with the heat from the sun will melt the snow on the roof. The melting snow, now water, runs down the home’s roof underneath the snow. When it hits colder areas such as the soffits, valleys or gutters it will begin to refreeze. The continuous thawing and refreezing are what causes ice dams. When the ice dam forms, water backs up under the roof shingles and will find its way through the roof subsystem, sheathing and cause water damage to areas such as ceilings and walls.
How to Protect Against Ice Dams
Protecting your home from forming ice dams is three-fold. First, it is important to have a proper roofing ice and water protector underlayment. This waterproofing underlayment is applied prior to nailing roofing shingles. Ice and water shields, typically a self-adhesive specialized rubbery protector, is used in low pitch areas, around dormers, in roof valleys, around vent stacks, skylights, roof ridges, hips and eaves. These special materials help prevent water backup due to ice dams when properly installed.
The second line of defense to protect against ice dams is having the proper amounts of insulation which will keep heat from escaping from your home’s living space. If the heat is not allowed or is minimal escaping into the attic it will not be able to warm your roof deck and melt the snow, thus helping prevent ice dams.
The third area of concern is attic ventilation. Proper ventilation removes any heat and helps keep the roof deck an even cool temperature. This will prevent snow from melting and forming ice dams.
If you have ice dams forming on your roof you should contact a professional roofing company to have your roof thoroughly inspected. Fully understanding the reason your roof is forming ice dams is not something an inexperienced roofer can identify and it’s best left to a company that has the experience and training to identify the cause of your ice dams.
For help with your homes roof call (301) 870-2145
267 Kentlands Blvd
Gaithersburg, MD 20878