Putting De-Icers on a Roof

Lillian in NH


Can I put magnesium or calcium chloride on my roof to melt the snow? I saw something on TV that says I can.

While I’ve heard of people putting this on their roofs, I am strongly opposed to it. The argument is that calcium chloride isn’t corrosive like your typical salt (sodium chloride); but the fact of the matter is that the corrosiveness comes from the chloride. The issue also isn’t with the asphalt shingles (although calcium chloride will likely leave a white stain on your roof), but it’s the corrosiveness to metal. So, metal roofs are a big no-no for chlorides and asphalt roofing can be just as bad because the melting solution can creep under the shingles and begin corroding the galvanized nails. One other caution is the fact that as the melting snow filled with chloride comes off the roof, it enters your landscaping with detrimental affects to your foliage. So….my personal opinion is, don’t do it! If you absolutely have to put something on the snow & ice to melt it, look for some green solutions at greenicemelt.com.