Chicago just had its first major snow storm of 2016 and all of the sudden people who were running around in shorts last week are now shoveling snow in their thick winter jackets. Oh, Chicago, how do you manage to get us by surprise… year after year, after year?

Clearing the snow on the ground is important, but don’t forget your roof! The main reason you should keep your roof as snow-free as possible is that it’s crucial for preventing ice dams from forming on your roof. Obviously, ice dams can’t form without snow.  If you’re able to prevent ice dams, you’re far more likely to prevent your roof from leaking and damaging the inside of your home.

Another reason roof snow removal is so important is that it’s a good idea to keep all that excess weight off your roof.  As a rule of thumb, one square-foot of snow that’s one-inch in depth weighs about a pound.  If your roof has 12 inches of snow on it, that could easily amount to thousands of pounds of stress on your roof.  That’s not even counting the weight of any ice dams that may form as a result of leaving the snow on your roof; just one cubic foot of ice weighs 57 pounds, and a typical ice dam can weigh thousands of pounds.  Minimizing the stress placed on your roof is a great way to minimize the risk of leaking and cave-ins (the latter of which occur more frequently than you might think).

You can help prevent serious damage to both the roof and inside of your home by minimizing the likelihood that an ice dam will develop, and by removing one as soon as you spot it. Ice dams can form when water from melting snow re-freezes at the edge of your roofline. Without roof snow removal, an ice dam may grow large enough to prevent water from draining off the roof. This water can then back up underneath roof shingles and make its way into your home.

Remove snow from your roof after every storm. To begin with, use a roof rake to clear snow from the edge of your roof upwards of three to four feet immediately after each storm. In addition to helping prevent an ice dam from forming, this will lessen the stress on your home’s roof. The amount of snow and ice your roof can support will depend on a number of factors, including the roof type and the age and condition of the structure. But a good rule to keep in mind is if more than a foot of heavy, wet snow and ice has accumulated on your roof, you should have it removed.

How do you know if you have an ice dam? Look carefully at the icicles around the exterior of your house. If they are confined to the gutters and there is no water trapped behind them, then an ice dam has likely not formed. Nonetheless, icicles can pose a danger to people when they fall off, so try to safely knock them down while standing on the ground, making sure not to stand directly beneath them. If you cannot safely reach them from the ground, consider hiring a contractor to help.

Check for water stains or moisture in the attic or around the tops of exterior walls on the top floor of your house. Stains and moisture may indicate that an ice dam has formed and water has penetrated the roof membrane.

Melt the ice dam. Fill a nylon stocking with calcium chloride ice melt, and place it vertically across the ice dam so that it melts a channel through the dam. If you try this, make sure you can safely position the ice melt on your roof, and make sure to use calcium chloride, not rock salt. Rock salt will damage your roof. Also, be aware that shrubbery and plants near the gutters or downspouts may be damaged.

Get professional help. If you cannot safely reach the roof, avoid using a ladder in snowy and icy conditions. Consider hiring a contractor to remove the ice dam.