The winter of 2008-2009 was a particular bad one for ice dam formation and related problems because of the long stretch of cold temperatures without intermittent melt off events. Ice dams are caused by excessive heat loss melting the snow on the roof and the resulting water freezing at the cold overhangs. As the melting water continues to run down the roof, it pools behind the ice dam and forces its way under the roofing material. Even a layer of ice and water shield may not be enough if the ice dam becomes too large as shown in the photo above. However, if applied correctly, Ice shield can usually prevent water entry into the home. We have found over many years of installing roofs that the conventional wisdom in regards to the proper installation techniques of ice and water shield is flawed.
INSTALLING ICE AND WATER SHIELD
We also recommend installing heat tapes into the gutters and downspouts. Standard heat tapes available through Don Ables, Valley Lumber, or Home Depot will work. Consult an electrician for your electrical outlet limits.