Frequently Asked Questions > Ice Dams

At Siders we take great pride in providing our customers with the service and information they need to understand and care for the products they have purchased. We are always available to assist you, and we want to provide you the best customer service available. The following information is designed to address some common questions and concerns.

 

Ice dams can occur when heavy snow builds up on a roof. Roof overhangs are the coldest part of the roof because they extend out past the walls of your home. For this reason, ice build-up usually occurs around your overhangs and gutters, while snow on the rest of your roof may melt. 

 

Ice dams can also be found at the rooflines of built out windows such as bay, bow or garden windows.  Often, people mistake water infiltration from ice dams for leaking windows. There is a simple way to identify the difference; if the window only leaks in the winter, and doesn’t leak in the summer rain, the problem can be properly identified as an ice dam.

 

Ice Dam Formation

Ice dams are formed by temperature changes after snow falls. During the warmer hours of the day, some of the snow from your roof melts, and gravity directs the water to flow towards the ground.  The water then refreezes when temperatures later drop, forming an underlying ice barrier. This ice barrier is generally located at the bottom of the roofline where it meets the overhang; this is called the freeze line.  Once an ice barrier forms at the freeze line, the daily warming cycle is not sufficient to melt through it, and any subsequent melting snow cannot flow away from your home through your gutters. This water then backs up underneath shingles, damaging the attic, ceilings, and walls. 

Three things are required for an ice dam to form:

  • Snow
  • Heat to melt the snow
  • Cold to refreeze the melted snow into solid ice
Tips to Help Prevent Ice Dams
  • Insulation is a major factor in keeping ice dams at bay. Homes in the northern United States should be equipped with ceiling insulation of at least R-38 (about 12 inches of fiberglass or cellulose). This insulation should be consistently applied to all floor areas in your attic and then sealed so that no living space heat can escape. 
  • Ventilation is another key factor in preventing ice dams. A soffit-to-ridge ventilation system is the most effective ventilation scheme you can use to cool roof sheathing. Power vents, turbines, roof vents and gable louvers do not perform as well and therefore are not recommended.
  • Air Leakage: Insulation restricts heat loss, but a special effort must be made to block the flow of warm indoor air into the attic or roof area. Small holes allow significant volumes of warm indoor air to pass into attic spaces.  In all construction, avoid making penetrations through the ceiling whenever possible. When you can’t avoid penetrations or when you need to air-tighten existing holes, use urethane spray-foam (in a can), caulking, packed cellulose, or weather stripping to seal all ceiling leaks like:
    • Wire penetrations
    • Plumbing penetrations
    • Ceiling light fixtures
    • Attic hatches
    • Chimneys
    • Bathroom exhaust fans
    • Intersections of interior partitions with the ceiling
  • Be sure to check all insulation and ventilation in your attic before the start of winter. Fill any holes in the insulation to make it airtight, and make sure all vents are clear of debris to allow air to flow through.
  • You can remove snow buildup as it accumulates around your roofline by raking the snow off. Buy an extension attachment for your yard rake that will allow you to reach your roofline from the ground level. Use caution when doing this or any other outdoor winter project to prevent accidental injury from slipping. Never climb ladders to accomplish roof snow removal; ladders are always dangerous, but in winter, the risk of slipping increases dramatically.
  • Calcium chloride can be applied at your roofline, and in your gutters to help melt snow and ice. It is available at most local hardware stores. It works best if you put the product in an old pair of stockings and place them in your gutters before any major snow falls.

Ice Dam Myths

Contrary to popular belief, gutters “do not” cause ice dams. However, gutters can allow ice and water to concentrate at vulnerable roof-eaves areas, particularly if the gutters are not clear of debris. As gutters fill with ice, they often bend and rip away from the house bringing down fascia, fasteners, and downspouts. Ice dams are ultimately a direct sign of heat loss. 

 

If you notice that snow is melting in specific areas of your roof, you may want to have a licensed contractor check the insulation in your attic space.  Your attic space should be the same temperature as the outside air to prevent ice damming.

Ice dams can form with as little as 1-2 inches of snow accumulated on a roof, followed by several days of cycling temperature changes

Siders LLC

  • Jeremy of Siders LLC is located in Traverse City, Michigan. Siders LLC specializes in installation of vinyl siding, vinyl shake impressions, custom aluminum trim, repairs, windows and more. Siders LLC provides free estimates and is fully insured. Browse through our site and call (231) 409-8257 or click here for more information. Read More...