Noticing ice dams on your roof is the first step in repairing the problem.  Ice dams are a problem because they can cause water damage or structural issues for your home.  Here are some of the more common ways ice dams can be prevented with the help of professionals.

The first solution is to apply a rubber, waterproof layer to last 8 or 10 courses of shingles on your roof.  This does not prevent the ice dam from forming, but it will hinder the standing water from seeping between the shingles.  The second option is to install heating cables along the edge of the roof to combat freezing ice.  The cables ensure that the ice melts and runs free of the roof.  The final solution ensures that the problem ceases to happen, by insulating the attic to prevent warm air from heating the roof.

These methods are all beneficial to preventing the damage of ice dams and snow build-up.  However, professional roofers should perform these techniques.  Consider calling roofing professionals in your area to do the job.

Source:  http://www.erenovate.com/articles/roofing/understanding-and-eliminating-ice-dam-roof-leaks