Ice Damming: Case Studies in Diagnosis and Remediation PDF

Ice damming is a problem that annually affects a large number of buildings in Canada. It is generally associated with interior leakage and with accompanying mold and rot and can also present a danger of falling ice. However, it can also affect the service life of roofing materials and components, even if leakage to the interior doesn’t occur.

Ice damming is a building science issue that arises from differential melting and freezing of snow on a roof. The root causes of the melting are frequently far from the roof deck. As a consequence, methods to alleviate ice damming often treat the leakage without addressing the fundamental cause. Such methods can reduce or eliminate the leakage in the short term but, because they do not address the cause of the melting and freezing, they often do not provide a long-term solution. In addition, they frequently do not address the durability issues caused by ice buildup on the roofs. The best solution is to determine the causal factors and undertake appropriate remediation in order to solve the problem on a longer-term basis.

This paper will discuss the factors that contribute to ice damming through detailed case studies on three low-rise condominium complexes in Ottawa, Ontario, Canada. Each complex has suffered severe ice damming since its construction. To develop a remediation strategy, we performed a systematic diagnosis of the cause of the ice damming and the implementation of trial repairs at each site. These trial repairs were monitored (temperature and visual indicators), and it was found that the suggested repairs had some benefit on two sites and little benefit on the third.

The aim of this paper is to present a methodology to provide long-term solutions to the problems associated with ice damming, with emphasis on utilizing sound building science knowledge and principles.