Ice Dams – How They Happen and How to Stop Them
Ice dams can start forming as soon as there is snow on your roof and there are continued freezing temperatures. Since that basically describes most of our wonderful Minnesota winters, ice dams are a big issue for many homeowners in our state. Ice dams form when the temperature of your attic is above freezing, which results in heat escaping and warming the underside of your roof. This melts the snow on top of your roof, which runs down to the lower part of your roof where the temperature is below freezing where it refreezes ( look at the picture below for a visual). Ultimately the cause of ice dams is hot air warming your roof and melting snow.
Often we see Minnesota homeowners treating the symptoms of ice dams rather than the cause.Most of these will not solve the problem of your ice dams, and only shorten the life of your roof. Heat coils will NOT help your ice dams – they only waste energy and are bad for your shingles. Most of the time the process of removing snow and ice can be dangerous, labor intensive and damaging to your roof. Please never get up ON your roof to hack away at the ice – that is extremely dangerous!
So if you can just keep your attic as cold as the outside temperature (that is, below freezing) then you are on your way to preventing ice dams. The best way to make sure your attic stays cool is to seal attic air leaks. Hot air can leak into your attic around what are called “attic bypasses” – or any crack or hole large enough to allow air to pass through. Often these can be found around chimneys, plumbing stacks, dropped worries and recessed lighting. So, the best way to treat the symptoms of ice dams is to make sure your attic is properly air sealed!