Rock Salt.

For bulk truck quantities (20+ tonnes per delivery), the major Canadian sources are Compass Minerals from the Goderich, Ontario mine (the largest salt mine in the world), K+S Windsor Salt (Pugwash, Nova Scotia and Lindbergh, Alberta), and Cargill via cross-border supply from Cleveland, Ohio. We hold supply contracts with all three and deliver to depots in every province with 24–72 hour lead time during the season. For pallet and 20 kg bag quantities, Home Depot Canada, Lowe's Canada, Canadian Tire, Rona, and Costco Canada stock through the fall and winter. For mid-volume orders (1–5 tonnes) the right channel is a regional landscape-supply yard or a snow-removal contractor with bulk capacity — the price per tonne is 20–40 % below retail bag pricing.

Untreated rock salt is straight sodium chloride mined and screened to gradation. It activates the melt reaction by absorbing pavement moisture, then exothermically releases heat that melts surrounding ice. The reaction slows dramatically below –10 °C. Treated rock salt is pre-coated with a liquid de-icer — typically calcium chloride brine, magnesium chloride brine, or an organic-blend brine like beet juice or corn-syrup byproduct. The liquid coating starts the melt reaction the instant the salt hits the pavement, extends effective melt temperature down to –25 °C, reduces bounce-and-scatter, and cuts application rates by 20–35 %. Treated salt costs 15–40 % more per tonne but the lower application rate and wider temperature range usually make it the lower total cost per cleared square foot for commercial routes.

Standard commercial calibration is 4–8 lb of rock salt per 1,000 square feet of paved surface, with 6 lb being the most common middle-of-the-road rate. A 50,000 sq ft commercial parking lot at 6 lb per 1,000 sq ft consumes 300 lb (about 136 kg) per salt application. With a typical Canadian commercial route doing one pre-storm anti-icing pass and one post-storm de-icing pass per storm event, and 12–20 storm events per season in southern Ontario, southern Québec, and the Lower Mainland, that same 50,000 sq ft lot consumes 7–12 tonnes of rock salt per season. Properly calibrated salt spreaders cut total seasonal consumption by 25–40 % vs. visual estimation, which is why every spreader we sell ships with a calibration chart and the procedure to verify discharge rate.

Rock salt does not chemically damage cured asphalt or properly sealed concrete at spec application rates. The damage homeowners attribute to rock salt is almost always freeze-thaw spalling — brine penetrates concrete pores, refreezes during the next cold snap, expands, and chips the surface. This is worse on concrete less than 12 months old, unsealed concrete, low-air-entrainment concrete, and aggregate exposed concrete. For new driveways and decorative concrete in the first season, switch to calcium magnesium acetate (CMA) or potassium acetate — both are non-chloride and do not cause freeze-thaw damage. For all other situations, standard rock salt with an annual penetrating concrete sealer is the right combination. Asphalt is generally unaffected by rock salt at any application rate.

High concentrations of sodium chloride do damage grass, shrubs, and salt-sensitive landscape plants — typically as die-back along driveway edges and around storm-drain catchments where meltwater concentrates. The threshold for visible turf damage is roughly 2,000–3,000 ppm sodium in the root zone, which corresponds to repeated over-application or runoff pooling. Solutions: keep application rate at spec (4–8 lb / 1,000 sq ft), use drop spreaders not broadcast spreaders near landscape beds, and switch to potassium chloride or calcium magnesium acetate (CMA) for landscape-adjacent walkways. For pet safety, all chloride de-icers (sodium, calcium, magnesium, potassium) cause paw irritation if dogs walk through fresh application. Pet-safe ice melts marketed for residential use are typically urea or propylene glycol blends that do not crystallise on paws.