- Mary Caldwell For the AJC
If it's one of those mornings when metro Atlanta road conditions are expected to be rough after freezing rain and other precipitation, you may be wondering how you can get out of your driveway safely.
There are steps you can take – both before and after an ice storm – to help make things easier:
If you'd like to treat your driveway before the ice storm hits, use a de-icer or an anti-icer, which is basically the same thing in a different form. De-icers are usually in powder or pellet form and are sold in bags and buckets, while anti-icers are usually liquids that you spray on your driveway. They don't work well when ice has already formed, however, so if this is the case, you need a powder or pellet de-icer.
Also known as ice melts, de-icers shouldn't be used on driveways that are less than a year old because the material hasn't had enough time to cure and settle. Read the instructions on the bag or bucket and apply it in a thin, even layer. Avoid getting de-icer on your lawn or on plants, and keep pets away from it. Some are safer than others for pets but can still cause problems for animals with kidney issues.
De-icers can be used before or after ice has formed and after you've removed any layers of snow. The products are best applied with a spreader. If you don't have one, you can wear gloves and sprinkle it on using your hand or a cup. The following are some commonly used types, including information from Consumer Reports and the University of Maryland Extension concerning their pros and cons:
Rock salt (sodium chloride): works moderately quickly, is inexpensive and effective at 20°F, but can cause minimal to moderate damage to concrete and other surfaces and can be lethal to pets.
Potassium chloride: safer around pets and effective at 25°F. Generally good for gardeners but can damage grass and plants if overapplied.
Magnesium chloride: works very fast and safer around pets and plants, but can damage grass and plants if overapplied and can cause moderate to significant damage to asphalt and concrete. Good for temperatures of -13°F.
Calcium chloride: more effective than rock salt and fast acting. Can cause minimal to moderate damage to asphalt and concrete and can damage grass and plants when overapplied. Good for temperatures of --22°F.
Less toxic alternatives
If you'd like to take care of driveway ice without worrying about damage or toxicity, use products like cat litter, sand or birdseed. They don't melt ice, but they will help improve your traction, which can also come in handy if your driveway has black ice.
How salt melts ice
As you're fighting icy driveways and roads, you may wonder how salt is able to melt ice. Encyclopaedia Brittanica provides the following explanation:
As water turns into ice at 32°F, it usually has a thin layer of water on top of it. The water is melting the ice, but the ice is also freezing some of the water. At 32°, the rate of exchange stays about the same. When salt is added, it's able to lower the freezing point of water by making it harder for water molecules to bond together. The ice on the ground won't be able to freeze the water at 32°, but the water can still melt the ice.