Shingle roof systems are designed to channel water from the high points of the roof to the lower sections where it should exit the roof either into a gutter system or simply onto the ground. Most shingle roof systems are not designed to hold water or prevent water that runs or is blown uphill from entering the building. Ice dam related leaks are caused simply because the water could not escape from the shingled roof area. This condition is normally not a design flaw with the roofing system or an indication of a poorly installed roof. Ice dams are a result of winter storm conditions which prevent the shingle roof system from shedding water as designed.
Ice dams cause millions of dollars of damage every year.
Many building owners report conditions that resemble a rainstorm in their building. Not all damage is obvious and some hidden damage can go unchecked. Roofing material should not sustain damage but it needs to be inspected. Shingles that have been heat damaged can be crushed and pulled loose as a result of the additional weight of the snow and ice. Gutters and downspouts can pull loose, swell, and burst from freezing water.