Controlling Potential Water Damage Due to Ice Damming

The roof around the entries to the upper condo units in Building #1 had similar sized ice dams. Once the ice dam has formed the only reasonable solution to prevent the water from backing up under the shingles is to melt a small portion of the ice dam at its thickest location to create an opening (valley) for the water to run off. The water will then leak to the ground and not up under the shingles. 

This was accomplished by putting Calcium Chloride in a permeable bag, sock or nylons. Calcium Chloride comes in a bead or flake form and is highly soluble in water. It is the best ice melting product available. When Calcium Chloride comes in contact with ice/water there is an exothermic reaction. This heat aids in melting the ice faster in temperatures down to minus 40ºC. It is safer for pets, concrete/asphalt and vegetation compared to the bags of rock salt.

In this case, a small nylon stocking was filled with Calcium Chloride and was set on top of the thickest point of the ice dam using an extension pole after the snow on top of the ice dam was removed. Depending how thick the ice is and how much Calcium Chloride is in the bag a second bag may be required to melt the ice to the desired thickness. A second bag was required to melt the dam to create an opening. The same extension pole was used to retrieve the bag after the melting was complete.

The best time to melt a valley in the ice dam is when the ice dam first starts to form.  When subsequent ice dams form the above procedure is repeated.

This short video illustrates the general cause and effect of ice damming in the OGT, specifically in between Buildings 1 and 2 .

This presentation illustrates the general cause and effect of ice damming in the OGT, specifically in Building 7.