At what temperature does rock salt stop working?
Rock salt works best above about 15°F, measured at the pavement, not in the air. Below that it slows down sharply, and liquid magnesium or calcium chloride, which work down to about -10°F and -20°F, take over.
Pavement and air temperature are often ten degrees apart. A sunny lot can be above freezing at dusk with the air at 30, and a shaded loading dock can be below 15 when the forecast says 25.
Salt brine works in the same range as rock salt. It is faster and easier to place, not colder.
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More on salt & ice
- Why is my parking lot icy even though it was salted?
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- What is pre-treatment or brine, and is it worth it?
- Is sand better than salt for ice?
- Does salt damage concrete sidewalks?
- What is the difference between rock salt, calcium chloride and magnesium chloride?
- What ice melt is safe for pavers and natural stone?
- Is ice melt safe for pets and landscaping?
From JRW Services LLC, commercial snow and ice management across Sussex, Passaic, Bergen, Morris and Warren counties, NJ. All answers
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