Buyer’s guide for de-icing products

First, remember that price should not be the sole selection criterion for a de-icer. The two main factors to consider are: the temperature limit at which the de-icer will continue to be effective and its corrosive potential for materials and the environment.

Sodium chloride (ice salt):

• Advantages: inexpensive but performs poorly when the temperature is below -10°C.

  Disadvantages: Very corrosive; damages concrete and plants; needs heat (sun, etc.) to be activated; leaves white stains.

Calcium chloride:

• Advantages: Effective down to -30°C; quick-acting; less product required and less damaging for the environment than sodium chloride when applied as directed.
• Disadvantages: More expensive; corrosive for unpainted metal; can damage surfaces and plants if applied excessively.

Magnesium chloride:  

• Advantages: Less chlorine than calcium chloride; characteristics similar to ice salt but less efficient, only works down to -25°C; the least damaging salt for concrete; non-toxic for plants and animals if used as recommended;
• Disadvantages: Corrosive for metal; may damage surfaces and plants if applied excessively.

But which is best: sodium chloride (salt), calcium chloride, magnesium chloride or a careful blend of all of these? The fact is that several mixtures contain melting agents that work at different temperatures and are formulated to limit damage to surfaces.

One thing is certain: the crumbling of concrete and asphalt is the result of repeated freezing and thawing cycles. So it’s better to choose a de-icer that provides long-term protection against re-freezing.

Your purchase should also be determined by the quantity of de-icer needed to remove ice from a given surface area. It may be better to pay more for a product that will de-ice four times more surface, more quickly, at much lower temperatures and with less environmental impact.

Three good choices in different situations:

• Combine de-icing products with abrasives to reduce the use of salts.
• Use magnesium chloride when temperatures allow.
• Use calcium chloride in very cold temperatures, preferably as part of a mixture.

Advice on use

Moderate use and following the manufacturer’s coverage recommendations are essential.

For materials:

• Apply just enough de-icer to detach the ice from the surface.
• Remove the snow and ice as soon as the product works so as to minimize secondary effects.

Note that no de-icer should ever be used on concrete less than two years old since the material contains lime residues that can cause scaling when in contact with chloride. Similarly, it is not recommended for spreading on concrete that is non-air-entrained, cracked or scaled, or on masonry (brick, stone, etc.).

For vegetation:

• Disperse the snow and ice as you dislodge it, since heaps will produce excessive concentrations of de-icer when it thaws.
• Grass will look better in the spring if it has had a winter protection blanket. This  should be removed as soon as the snow is gone.
• As soon as spring arrives, water areas that might have been affected so as to wash away any de-icer residue.

An accident?

And if, despite all your efforts, a visitor slips on the ice and is injured, your liability coverage in your home insurance policy could compensate them under certain conditions.

Our thanks to Warwick Salt.