What Is an Ice Dam?
An ice dam is a ridge of ice that forms at the lower edge of a roof and prevents water produced by melting snow from draining off the roof. The water that backs up behind the dam can leak into a building and cause damage to walls, ceilings, insulation and other areas.
What Causes Ice Dams?
Non-uniform roof surface temperatures lead to ice dams. Heat loss from a house, snow-covered roof and outside temperatures interact and lead to ice dam formation. For ice dams to form, there must be snow on the roof, and, at the same time, the upper portions of the roof's surface must be above 32 degrees F, while lower surfaces are below 32 degrees F. For a portion of the roof to be below 32 degrees F, outside temperatures must also be below 32 degrees F. ( When we say temperature above or below 32 degrees F, we are talking about average temperatures over sustained periods of time.)
The snow on a roof surface that is above 32 degrees F will melt. As water flows down the roof, it reaches the portion of the roof that is below 32 degrees F and freezes. This creates an ice dam.
The ice dam grows as it is fed be the melting snow above it, but it will limit itself to the portions of the roof that are, on the average, below 32 degrees F. So the water above backs up behind the ice dam and remains a liquid. This water finds cracks and openings in the exterior roof covering and flows under the shingles. From the attic, it could move into exterior walls or through the ceiling insulation and stain the ceiling finish.
Prevention
Some steps you can take to help prevent ice damming from occuring is first to make sure you have enough insulation in your attic. Although you will always have some heat loss going into your attic this will minimize it as well as saving money on heating fuel. Second make sure your roofing contractor installs a waterproof underlayment directly beneath the shingles. For a 1 foot overhang 3 to 6 feet of underlayment should be installed. The larger the overhang the more waterproof underlayment is needed. Last you must remove the snow that accumulates on the roof edges. I would recomend purchasing a roof rake with a long handle to reach up as far as you can to remove snow, usually 4 to 8 feet from your roof edge. This will let the Sun naturally melt off that non-heated soffit or overhang area as your shingles warm up.
Our Services
Our trained proffessionals at the Gutter Supply Company can supply thhe materials and labor needed to rake off your roof. Please don't wait until water damage occures. When there is significant snow on the roof we can rake it off right away so the ice dams won't form. Call us at 262-966-7388 if you live in southeast Wisconsin or the Milwaukee area for our rates. We have experienced Gutter Installation Proffessionals who will do the job right!!!!
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