Have you ever gone by a home and noticed long icicles hanging from the eavestroughs? These accumulations of ice are not only a physical hazard they can cause leaking of a roof. The cause of this problem, commonly called ice damming, occurs when warm air escapes from the living areas into the attic. This warm air heats the roof and melts the snow. Water running down the roof under the covering of the snow, will re-freeze at the cold eaves. When ice forms it prevents water from draining off the roof. This “pooled” water, above the ice dam, will seep under any layered roofing system. Ice dams are also responsible for clogged and damaged eavestroughs, wet insulation in the roof and walls. Wet wood, paint failure, and decay will result if the problem persists.
Several measures can be taken to eliminate ice damming. Seal all attic penetrations, for example, around bathroom exhaust fans, plumbing vents, electrical wiring and outlets, with caulking or weather stripping. Vent all exhaust fans outside through the roof. Install an appropriate amount of insulation in the attic. Provide adequate and effective ventilation. Cold air should completely wash the underside of the roof above the insulation. This ventilation includes not only soffit and roof vents but also pre-formed baffles to ensure attic insulation does not block ventilation paths.
Eliminating the potential for ice damming by maintaining a well ventilated roof will save money and aggravation.