We offer the following facts about Ice Damming to help homeowners understand what they are dealing with. Ice damming is the result of snow melting on the upper portions of a roof, then re-freezing on lower portions of the roof. The “melting” we are referring to is that caused by warm air from the heated interior of the home escaping into the attic above. As the home’s interior heat escapes into the attic, it warms the underside of the roof deck and begins to slowly melt the snow that is resting on the roof. The melting snow drains down the roof, then begins to freeze again once it reaches that point where the roof extends beyond the exterior wall of the home (i.e. the roof overhang / eave) because that portion of the roof does not get warmed by the escaping heat from the interior of the home. The longer snow remains on a roof, slowly melting on the upper portion of the roof and re-freezing along the roof eaves below, the bigger the ice dam becomes. Eventually, the growing ice dams become so tall that the melting snow above can no longer drain over the growing ice dams below. Once this happens, water begins to back up under the shingles and leaks into the interior of the home. This leakage will typically then continue until the melting snow on the roof can once again drain off of the roof (i.e. will continue to leak until the ice dam is gone or no longer big enough to cause water to back up under the shingles).
There are numerous factors which contribute to the development of ice damming, including; how much heat escapes into an attic, how well ventilated the attic is, how steep the roof is, how long snow remains upon the roof, how far the roof extends beyond the exterior walls of the home, what type of roofing material is on the home, the design of the roof, the direction the roof slopes face, etc. etc. In short, there are typically numerous contributing factors which impact the potential for ice dam development. There is typically no guaranteed “cure” that can reasonably be expected to 100% prevent leakage attributable to ice damming because the typical home does not 100% prevent heat within the interior of the home from escaping into the attic, and the typical home does not have an insulated roof deck that will remain below freezing as warm air escapes into the attic. That being said, there are still ways to significantly “help” protect against leakage attributable to ice damming. The most practical / common method is to have an ice barrier underlayment installed along the roof eaves, extending a minimum of 2-feet beyond the exterior walls. The second most practical method is to have heat tape installed along roof eaves. Neither should be considered a 100% assured means of protection, but both are reasonably likely to prevent or greatly reduce the potential for leakage attributable to ice damming.
Should you encounter a leak due to ice damming, the first priority we suggest is to have the ice dam physically removed so water can drain off of the roof. This should provide immediate relief from leakage. The next step would be to have permanent repairs completed which may “help” prevent further occurrence. Permanent repairs may simply involve one procedure, or may involve numerous procedures, depending upon the specific conditions relating to the structure.
For roof related issues, you can count on WCC Roofing Co. (your most trusted & knowledgeable roof contractor) to provide a thorough assessment of the specific conditions of concern, followed by a free written proposal for any roof repairs we may suggest.