What is an "Ice Dam" And Why is it So Dangerous to My Home?
In northern areas where winter temperatures frequently drop below freezing, a phenomenon known as an “ice dam” can cause serious and expensive damage to a roof and to the structure of a home.
Ice dams are formed at the lower roof edge by the cycle of thawing and re-freezing of melted snow on the overhang. When snow accumulates on the roof, the weight and pressure of the snow pack compresses and can form a layer of ice on the roof deck.
Warm air in the attic heats up your roof deck and melts the bottom layer of snow or ice that is sitting on your roof. The water then trickles down toward the roof’s edge where it once again encounters frigid air, causing the water to refreeze. Gutters that are clogged with last fall’s leaves can make the situation even worse.
The refrozen snow melt forms an impassable ice dam that can force water up and under shingles, causing leaks in your roof. A leaky roof can lead to a host of other structural problems in your home, including warped framing, stained walls and ceilings, and weakened foundation.
Preventing ice dams from forming requires several steps. The most important is ventilation.
Proper roof ventilation installed by a professional roofer can help prevent the formation of ice dams. A quality ventilation system helps balance the temperature differential between the air in the attic and the air outside. This minimizes the chance that the snow pack on your roof will melt from the bottom up.
By balancing the temperature of the roof, the first step in the formation of ice dams is eliminated. The snow will not thaw and then re-freeze since the temperature will not change dramatically enough for that to occur. This will keep your roof, and your home, safe from the dangers of water damage. A second step is to make sure gutters are clear of debris and blockage, allowing snow melt to flow freely. A gutter protection systems can help keep gutter troughs clear.