What causes these winter headaches? The insulation thickness and ventilation characteristics in the attic are typically insufficient. Heat loss through little or no insulation melts the snow, causes a dam to develop at the cold eves (roof overhang), and water then enters house. To prevent ice dams, hold back insulation at the soffit vents, install a bituminous membrane on the roof deck at the eves when re-roofing or at new construction, aim for an R-value of 30, and ventilate the attic!!! Call me - and I'll fax you a fantastic drawing I have put together that explains the whole story.

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