From the desk of Fire Marshal Fred Baker
With all of the snow we have received this winter, the problem of ice dams will be on the rise again. The resulting water damage to a home can be devastating and extremely costly to repair.
Some homeowners have resorted to installing ice melt systems that are attached to the roof and in the gutters and downspouts. This, however, is only treating the symptoms -- not actually solving the problem. To solve the problem, one must first understand what caused ice damming to occur.
Ice damming occurs when heat escapes from the home, up into the attic and causes the bottom layer of snow on the roof to melt. The water then runs down the roof until it reaches the eaves where there is no heat escaping, and refreezes. Rinse and repeat. This melt/freeze causes an "ice dam" to be created, backing water up under the shingles where it then runs down the inside of the exterior walls in your home.
So, how do we prevent this from happening? First, you want to stop all of your expensive heat from escaping into your attic. The biggest offenders that allow heat to escape are recessed light fixtures and poorly sealed attic access openings. Also light fixtures, bathroom exhaust fans and anything else that penetrates the ceiling membrane between the heated space and the attic.
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First, if recessed lights are older style they are definitely "leakers," allowing lots of warm air to escape. Do not go up in the attic and throw insulation over the lights; this may cause a fire, and batt insulation is not a good sealant. Kits are available for converting older "can" lights in to modern/energy efficient fixtures. Second, make sure other fixtures have gaskets to seal against leakage.
Another important issue that is usually not fully understood by the typical homeowner is attic ventilation. In most homes, the attic is supposed to be a cold location (in the winter) because it is properly ventilated with louvers in the gables, soffit and ridge vents or some combination. This ventilation is required for two reasons: One is to remove any moisture that escapes from the home and the heat that usually comes with that moisture.
So closing up those attic vents to "keep the cold out" is the wrong thing to do -- they need to be kept clear of any obstructions. In some cases, additional ventilation may be required.
And why is the fire marshal writing about ice dams? Because as with many things around the home, the ice melt systems previously mentioned can cause roof fires when not properly maintained and used. Like most equipment in our homes, they too need to be checked and serviced occasionally.
For further questions regarding this matter, call 203-594-3030.