The weather these past few Minnesota winters have lent themselves nicely to creating ice dams on homes and commercial buildings alike. All the melting, freezing, melting, re-freezing can really do a number on your roof’s shingles if your house’s insulation is poor.

So How Do Ice Dams Form Anyway?

When there’s a layer of snow sitting on your roof an ice dam is formed when the attic warms up enough to melt the first layer of snow on your roof. 

Drip by drip, the water will trickle down between the layer of snow and shingles until it hits the end of your roof. The edge of your roof stays cold because it extends beyond the attic—thus isn’t being warmed from underneath. There you have the gradual forming of nice mound of ice we call an ice dam...