An ice dam is a ridge of ice that forms at the eave or valley of a roof preventing proper drainage. This occurs when snow melts and slides to cooler portions of the roof and quickly refreezes creating the barrier or dam. The risk arises if additional melting occurs and water pools behind the dam. Costly damage may occur if the sitting water seeps between the shingle layers, wetting the roof deck and leaking into the home below.
Visible signs of damage may include dislodged roof shingles, water-stained ceilings, peeling paint, damaged plaster, etc. As other damage may not be as obvious, such as wet attic insulation, water within the wall frames or mold, any instance of ice damming should be investigated to avoid long-term structural and health issues.
The most common cause of ice damming is insufficient attic insulation and/or ventilation. To avoid this, the goal is to keep the attic very close to the outdoor temperature. Proper insulation will minimize excessive heat from escaping into the attic and through the roof. And adequate ventilation will quickly remove any warm air that might build up to help maintain a more uniform temperature. With the winter’s harshest snow still to come, consider the following helpful tips:.
- Inspect your insulation for gaps, cracks or areas that have settled, been compressed, gotten wet or have otherwise been compromised.
- Replace uninsulated ceiling (can) lights with those marked IC (the letters indicate the light is safe for direct insulation contact). Then insulate around and over the lights.
- Doors leading to unheated spaces should be addressed and trimmed as if they were outside doors, complete with saddles and weatherstripping.
- If your home has heating ducts that run through the attic, inspect them for leaks or improper insulation.
- Small air leaks from wall cavities into the attic should be sealed by a weatherization contractor. This will minimize the amount of heat that escapes into the attic and may save money on utility bills.
- Ensure that bathroom and kitchen exhaust ducts are vented to the outside. Otherwise warm and/or moist air can blow into the attic leading to warm spots and possibly reducing the effectiveness of the rest of the attic’s insulation.
- Clear existing gable or ridge vents of insulation, dust, vines, leaves or other debris.
- Soffit vents, which draw cool air into the attic through the eaves, should also be cleared of debris.
- The recommended minimum ventilation is one square foot for every 150 square feet of attic floor area.
- Ensure that there is at least one and one-half inch of space between the insulation and the roof inside the attic at the eaves to create a clear air path for improved circulation.
Finally, it is essential that you make sure gutters and downspouts are free of debris so melting water flows down and away from the house. Together, these tips will help to minimize your home’s risk and avoid ice damming.