Comparison of snow and ice melting products and their downsides
Icy winter weather conditions often create a need for the application of de-icers to slippery sidewalks, steps and driveways. Safety concerns often take priority over potential damage to paved surfaces, lawns and landscape plants, which may result from the use of certain de-icing products. This page describes the various deicer products.
Spalling Concrete The most common damage to concrete is spalling, and results from the concrete surface becoming pitted. Some de-icing products cause less damage to pavement. Also, sealing concrete in advance of winter weather can help prevent damage to concrete surfaces from de-icers.
Lawn Damage One defensive measure used by groundskeepers to minimize damage to lawn grasses from de-icers is an application of gypsum (calcium sulfate) to lawn areas bordering sidewalks, driveways and roadways. Applications of gypsum are best made in the fall of the year, prior to the onset of winter weather and subsequent de-icer applications.
Below is information on the most commonly used de-icers:
Calcium Chloride
Effective temperature
Down to -25°F to -50°F Fast-acting at all temps, since it gives off heat as it dissolves.
Concrete
Doesn’t attack concrete chemically.
Vegetation
Won’t harm vegetation at the recommended rate.
Residue
No powdery residue.
Note: Sometimes used in roof gutters to melt ice dams.
Magnesium Chloride
Effective temperature
Down to 5°F
Concrete
Increases the number of freeze-thaw cycles, which can damage concrete from freeze-induced expansion. Gradually attacks concrete chemically.
Vegetation
Environmentally safer than Calcium Chloride and Sodium Chloride, but does contain more chloride than other salty de-icers.
Residue
Tracks less than Calcium Chloride.
Potassium Chloride
Effective temperature
Down to 12°F
Concrete
Increases the number of freeze-thaw cycles, which can damage concrete from freeze-induced expansion. Doesn’t attack concrete chemically.
Vegetation
One of the safer de-icers around vegetation. Considered environmentally safe.
Residue
Some white residue.
Notes
Requires higher application rate.
NOTE: Some suppliers offer a product combining Potassium Chloride with Magnesium Chloride. Some companies claim their combination product “ensures a fast acting melt with long term performance”
Sodium Chloride – Rock Salt
Effective temperature
Down to 20°F
Concrete
Increases the number of freeze-thaw cycles, which can damage concrete from freeze-induced expansion. Doesn’t attack concrete chemically.
Vegetation
Sodium is harmful to vegetation. Most commonly used de-icer because of its lower cost. Loses its effectiveness below freezing temps.
Residue
Leaves a white powdery residue.
Notes
Mixed with calcium chloride to improve low-temp performance.
Urea – Nitrogen fertilizer
Effective temperature
Down to 15°F
Concrete
Increases the number of freeze-thaw cycles, which can damage concrete from freeze-induced expansion. Doesn’t attack concrete chemically.
Vegetation
One of the safer de-icers around vegetation. Considered environmentally safe.
Residue
Some white residue.
Notes
Less corrosive to metals and rebar since it doesn’t contain chloride. Requires higher application rate.
