Salting and De-Icing

Sodium chloride, ordinary rock salt, is effective down to roughly minus 10 degrees Celsius in practical field conditions. Below that, magnesium chloride and calcium chloride blends do the work, with calcium chloride remaining active at substantially lower temperatures.

Product selection is a temperature decision first and a surface decision second. On a cold, dry night below the working range of rock salt, applying more rock salt achieves nothing except cost and chloride load. On a garage deck, a young concrete pour, or a decorative surface, product selection changes again because of what chloride does to the material.

Chloride drives corrosion in reinforcing steel and causes surface scaling on concrete, and concrete under about a year old is particularly vulnerable. That is why new pours, ramps, garage decks, and concrete walks get treated with deliberately chosen products and controlled rates rather than the same blanket application used on old asphalt. Our concrete restoration crews spend the rest of the year repairing exactly this damage.

Chloride use in Canada is governed by the Code of Practice for the Environmental Management of Road Salts, which applies to organizations using more than 500 tonnes a year on a five year rolling average and to any organization operating in a salt vulnerable area. The practices it points to are the ones that also save money: calibrated spreaders, application rates matched to conditions, anti-icing instead of reactive over-salting, pre-wetting, and covered material storage that keeps stockpiles from leaching.

De-icing failures are salt on snow, wrong product for the temperature, uncalibrated rates, and no record of what was applied where.

Salt on packed snow. The most common failure in the trade. It does not reach the pavement, it refreezes into a slicker surface, and it convinces the property that the site was treated when it was not. We clear first, every time.

Wrong product. Rock salt below its practical working temperature is inert. Sites that experience genuinely cold events need a plan that switches product rather than increasing volume.

Uncalibrated spreaders. Over-application is expensive, damages concrete and landscaping, tracks into buildings, and loads the storm system with chloride. Under-application leaves the site untreated while the invoice says otherwise. Calibration is the difference.

Reactive-only treatment. Waiting until ice has formed to respond costs more material and produces a worse result than anti-icing before the event.

No record. Section 6.1 of Ontario's Occupiers' Liability Act requires written notice within 60 days of a snow or ice injury, served on the occupier or on the contractor hired to clear the site. When the question is whether a surface was treated, an application log with time, product, and location is the evidence. Verbal assurance is not.