Ice Dams - Relief and Prevention

Heavy lake effect snowfall, warm sunny days, freezing nights, inadequate or no soffit ventilation, poor attic ventilation, old deteriorated roofing tar paper.

The perfect conditions for ice damming and water backup resulting in giant icicles, ice falls, and roof leaks.

A typical ice dam on a slate roof near Cleveland, Ohio.

South and west facing roofs are more likely to experience ice backup problems. Even with good ventilation and roof design, a combination of wind blown snow drifts, warming of the roof slate, and deteriorated roof underlayment can cause leaks.

The first step is to remove some of the snow from the roof.

Removing a snowdrift on a slate roof. At this point the snow was about eighteen inches deep. The snow is pulled off slowly, a few inches at a time. Care must be taken so as not to damage the slate roof under the snow, and, not to damage any shrubs or bushes below the roof when the snow is pulled off the edge of the roof. It is very easy to catch and dislodge a loose slate.
The snow is only removed to within an inch or two of the slate.

Next, remove some ice to get some water off the roof.

An overflow channel cut into the ice dam.

This must be done with great care and by an experienced roofer. A small sharp ax in the hands of an amatuer will quickly cut through ice, roof slate, sheet metal and guttering. Only cut enough ice to relieve the majority of the ice dam and get some of the water flowing off the roof.

We then spread some ice melt granules on the channel and around the ice dam to help melt the remaining ice.

Prevention of ice dam leaks in the future will require additional roof work and may include additional attic ventilation, additional insulation and replacement of original roofing underlayment.