Evolving Ice Damming Solutions for a Changing Climate
Please note: The attached file below contains a paper from the BEST5 conference that is linked to a conference presentation in pdf format. Open with Adobe Acrobat for best results.
A recently completed mixed-scale residential development in the New England area experienced extensive ice damming at the roof surface during the winter of 2014-2015 that resulted in large ice formations and water entry. Roofs are designed to withstand a certain amount of snow load and anticipate an average amount of snowfall each year. Industry standards and code regulations have been developed for general ice dam protection. In sloped roof assemblies, ice dams can occur under a variety of conditions. In winter months, warm air can leak from the interior to the exterior at locations like roof penetrations or roof-to-wall interfaces which can cause snow melt. Snow can also be melted by heat transferred from the interior to the exterior through conduction in addition to the melting that occurs from the sun’s radiation.
With enough snow accumulation, snow will provide more resistance to heat transfer and will shade the roof surface from solar radiation to the point at which the predominant cause of melting is conduction rather than the sun’s radiation. This, in combination with below freezing air temperatures, can enhance ice dam formation. Thermal analysis software was used to determine the point at which snow reaches an insulative value great enough to allow the roof surface temperature to reach 32 degrees Fahrenheit.