Just what is an Ice Dam and what can you do about it?
Snow accumulates during the wintertime in Minnesota, it is a fact. Ideally, the snow would melt, travel down the roof into those squeaky clean gutters you cleaned last Fall and flow to the ground. The problem begins when that accumulated snow begins to melt and refreeze on your rooftop. The melting and refreezing cycle can gradually form a ridge of ice on the edge of your roof. Once that ridge, also called an ice dam, is formed and grows it can prevent other melted snow from draining off of your roof.
The melted snow backs up behind the ice dam and forms a pool of water that can leak into your home and cause all kinds of serious damage to walls, ceilings and insulation. This drawing shown on the U of MN Extension website is a great illustration showing how an ice dam is formed.
Heat loss from your home mixed with the snow cover on your roof and the outside air temperature all combine to create the perfect environment for ice dam formation. Ice dams can form with as little as two inches of snow accumulation. Deeper snow increases the likelihood and the size of ice dams. Every inch of snow accumulated on the roof insulates the roof deck a little more, trapping more indoor heat creating a higher risk of ice dam formation.
Water leaking anywhere in your home is no good. Water leaking from your roof will hit your attic insulation and often leaks down the wall frame getting trapped in the walls between the exterior plywood and interior vapor barrier. Water trapped in this area of your home can result in smelly rotting wall cavities. Mold and mildew can form on wall surfaces and interior and exterior paint may eventually begin to peel.
There are many do-it-yourself ways to remove ice dams and along with them come many ways to further damage your roof. I recommend contacting a professional not only to help you remove the ice dams, but also to identify what is causing the problem and discuss steps you can take to prevent ice dams in the future.