'Tis the season for Ice Dams
Updated: Dec 7, 2022
It’s that time of year again when ice dams can cause serious issues with your home. I was out in Lonsdale, MN doing a home inspection and ran across some pretty heavy ice dams on a house. These are generally caused by air in the attic being warmed by the home’s interior which results in melting snow on the roof deck. This water runs to the edge of the roof and freezes again which creates the dam. Water backs up behind this and eventually gets under the underlayment of the shingles and runs inside the home. This can cause drywall damage, wet insulation, and rot over time. A couple of simple steps can be taken to stop this from occurring.
Warm Air – Try to identify the source of the warm air. Usually, it is caused by a lack of insulation, bypasses into the attic (wiring holes run through top plates of walls, uninsulated scuttle hatch covers, recessed lighting, disconnected bathroom vent ducting, etc). Repairing any of these issues can make a substantial difference in temperatures in the attic. Ideally, you want your attic to be similar temperature as the outside ambient air temperature.
Ventilation – Ventilation is important to move air through the attic. Ideally, you want the airflow to enter the soffits and exit at the roof ridge. This takes advantage of convection and moves fresh colder air into the attic stopping the warmer air from building up and melting roof deck snow.
If these steps fail to stop the ice dam cables can be installed that will melt through the ice dam and leave a route for water to escape off the roof. These are somewhat unsightly but are effective in reducing the chance of an ice dam. If you already have ice dams the best way to rid your home of them is to hire a company to come out and apply steam to the ice to melt it. Chopping, cutting, or breaking up the ice dam is not recommended as this can damage the shingles.