Let's start by ending the myth that gutters cause ice dams. They don't. They just happen to be in the wrong place at the wrong time. That being said, what does cause those horrible ice dams?

First, an ice dam is a ridge of ice that forms at the edge of a roof and prevents melting snow (water) from draining off the roof. The water that backs up behind the dam can leak into a home and cause damage to walls, ceilings, insulation, and other areas. Large icicles often form on the roof's edge and sometimes reach to the ground. This heavy buildup of ice can damage gutters and downspouts as well as roofing and trim.

Cold outdoor air temperatures and a fresh load of snow on the roof starts the process. If the roof surface remains below 32 degrees, then the snow remains on the roof and does not melt. If the roof temperature exceeds 32 degrees, the snow will melt and run down to the edge of the roof. If the temperature at the edge is lower then 32 degrees, the water will re-freeze and ice dams will form. So the solution is to keep a cold roof.

How can you keep a cold roof? Two words, insulation and ventilation. With a proper amount of insulation in the attic (R-36 or 10 inches of fiberglass insulation is now the standard), you will limit the amount of heat loss into attic areas. By doing so, you maintain a cold roof surface. There will always be some seepage of heat into attic spaces, so installing adequate attic ventilation to exhaust that excessive heat before it melts the ice on the roof is the key. The best way to ventilate a roof is with the installation of soffit vents along with a ridge vent. This will allow the heated air to escape quickly.

So don't blame the gutters this winter for those troublesome ice dams and the damage that occurs. The fault is an inadequate amount of insulation in your attic and insufficient ventilation. Fix these deficiencies and you will help limit the headache of winter ice dams.