WHAT'S AN ICE DAM?

Ice dams are a common problem that homeowners deal with in the cold winter climate. An ice dam is ice that forms at the transition from a warm surface to a cold surface, such as along the overhang of a house. The build-up of ice is the result of ice or snow melting on the roof area over the warmer, living area of a building and then refreezing when it runs down and reaches the cold overhang. This wall of ice at the gutter line traps melting snow and ice further up the roof slope and can force it to back up underneath the shingles.

Damage associated with an ice dam are lifted shingles, rotted roof decking and/or fascia and soffit wood, and of course, water leaking into the drywall inside your house.

HOW CAN ICE DAMS BE PREVENTED?

Adequate attic insulation, proper roof ventilation and the necessary amount of ice and water shield are three ways how you can prevent ice dams from forming on your home.  Ice and water shield is a rubber-like asphalt and fiberglass membrane, that is applied at the gutter line, in the valleys, around chimneys, skylights and any other areas of the roof that would benefit from a leak barrier.

When installing ice and water shield above the gutterlines, it is necessary to install the proper amount.  The manufacturer recommends that the shield extend 24" within the heated wall of the house.  In other words, if you have an overhang of about 2 feet, you need to install at least 4 feet of ice and water shield (2 feet for the overhang, and 2 feet past the heated wall).  The ice and water shield also seals itself around nails and will divert any water that penetrates the roofing material to run to the gutter and not into the house.