Ice dams are the ice that forms along the eaves of the roof and in and on top of gutters after a snowfall. While clogged gutters can freeze and cause ice dams, ice dams are generally not caused by clogged gutters.
The Cause – After a snowstorm, snow will have piled up on the roof of your home. If this snow melts, it becomes water and it will run down the roof until it reaches the eaves, where it is no longer above the heated portion of the home, and it can freeze on the eaves and/or the gutters.
Insulation and ventilation are the two ways that an attic is cooled in the winter. Improper insulation and insufficient ventilation can result in heat leaking from the home into the attic and not being disbursed from the attic, thus causing the roof to become warm and causing the snow to melt. The snow will melt and begin to drain, until it passes to an area of the roof without a heat source. This water instantly freezes. It usually occurs directly above the supporting exterior wall and just above the gutter line.
The Result – The ice dams prevent proper drainage, cause dangerous icicles, add unwanted weight to the roof, and will eventually cause damage to the roof, eaves, and frame of the house.
The Solution – Regular thorough professional cleaning of the gutters, annual inspection of the top-side of the home, and proper insulation and ventilation in the attic can minimize or eliminate ice damming.
Poor attic ventilation will cause an Ice Dam to form. Once formed, an Ice Dam continues to grow with every thaw/freeze cycle
The Ice Dam prevents real drainage, causes dangerous icicles, adds unwanted weight to the roof and will eventually cause roof damage