What are they?
An Ice dam is exactly what the name implies, a barrier made of ice that prevents water from flowing off a roof.
Ice Dams result when water from melting snow on a roof flows to a roof’s edge and freezes.
Subsequent melting produces water that becomes trapped on the roof because the Ice Dam prevents it from flowing off into gutters or onto the ground.
Shingles are designed to shed water that runs down a roof, rather than protect against water pooling on the roof’s surface. Thus, standing water behind the Ice Dam backs up under the shingles and penetrates the roof sheeting. Obviously, significant damage can result.
This water backup can even make its way behind siding/brick façade and into basement walls.
However, damage from such leakage can be avoided or minimized with prompt action and maintenance.
What you should do:
The most effective way to prevent Ice Dams from developing is to keep the undersurface of your roof cold. Ice Dams most often occur when the layer of snow closest to the roof melts and runs down beneath the snow above. A cold roof prevents that deepest layer of snow from melting.
Two things contribute to keeping your roof cold, proper ventilation and adequate insulation. Make sure your attic is well ventilated and that the vents are free of snow and debris. Also, inspect your insulation for bare or matted spots (but don’t climb in your attic if you aren’t sure where to step-seek the assistance of a contractor).
Another way to prevent Ice Dam formation is to remove snow from you roof. Use a roof rake to remove snow from the lower 4-6 feet of your roof.
If damage has already occurred, a contractor can minimize future damage by doing the following:
- Locate water entry points within your home and install a temporary cover and drain system to direct away from the building. Have a contractor inspect foundation.
- Lower the temperature in the portion of your attic experiencing problems by improving ventilation or adding insulation.
Finally, when it comes to replacing you roof in the future, be sure your contractor installs an ice and water shield at the edges. These are very effective at preventing damage caused by Ice Dams. Today, most building codes require them.