The five de-icers and their melt floor
Five chemical compounds dominate Canadian de-icing — each with a different effective temperature and cost.
The five de-icers ranked by melt floor
| De-icer | Chemical | Effective to | Cost / tonne | Best for |
|---|---|---|---|---|
| Rock salt | NaCl | –10 °C | $180–$420 | Routine commercial, asphalt |
| Treated salt blends | NaCl + CaCl₂ coating | –20 °C | $250–$580 | Mid-range commercial |
| Calcium chloride | CaCl₂ | –32 °C | $700–$1,200 | Cold snaps, hospital frontage |
| Magnesium chloride | MgCl₂ | –26 °C | $550–$1,100 | Environmentally sensitive |
| Potassium chloride | KCl | –12 °C | $1,200–$1,800 | Pet-safe, landscape-adjacent |
| CMA (non-chloride) | calcium magnesium acetate | –10 °C | $3,200–$4,500 | New / decorative concrete |
Cost per kg and per coverage area
Cost-per-bag is the wrong metric. Cost-per-cleared-square-foot is the right one.
What it actually costs to clear 1,000 sq ft
| De-icer | Application rate | Cost per application |
|---|---|---|
| Rock salt at –5 °C | 6 lb / 1,000 sq ft | $0.55–$1.25 |
| Treated salt at –15 °C | 3 lb / 1,000 sq ft | $0.40–$0.90 |
| Calcium chloride at –25 °C | 3 lb / 1,000 sq ft | $1.05–$1.80 |
| Magnesium chloride at –20 °C | 3 lb / 1,000 sq ft | $0.85–$1.65 |
Annual budget on a 50,000 sq ft commercial lot
Standard 14-storm winter, 2 applications per storm:
- Rock salt program: $4,200–$8,500 / year
- Treated salt program: $5,400–$10,800 / year (50–80 % more, but 30 % fewer applications)
- Cold-snap-only calcium chloride add-on: $1,800–$3,200 / year extra
- Anti-icing brine program (pre-treatment): saves $2,000–$5,000 / year on post-storm salt
- 01Best price-per-warmth-range: rock salt above -10 °C
- 02Best on a -25 °C night: calcium chloride
- 03Best for dog parks: potassium chloride
- 04Best for stamped concrete and stone: magnesium chloride or CMA
- 05Most damaging to vehicles: rock salt and calcium chloride
Damage to concrete, lawns, and pets
Concrete damage by product
| Product | Cured asphalt | Cured sealed concrete | New / decorative concrete | Cost per damaged sq ft to repair |
|---|---|---|---|---|
| Rock salt | Safe | Safe at spec rate | Freeze-thaw spalling risk | $8–$22 |
| Calcium chloride | Safe | Safe at spec rate | Avoid | $12–$28 |
| Magnesium chloride | Safe | Safe | Marginal | $10–$24 |
| CMA / potassium acetate | Safe | Safe | Safe | — |
Landscape damage
- Threshold for visible turf damage: 2,000–3,000 ppm sodium in root zone
- Most damage: along driveway edges and storm-drain catchments where meltwater concentrates
- Mitigation: drop spreaders near beds (no broadcast throw), pet-safe / pot-safe blends for landscape-adjacent walkways
Pet safety
All chloride de-icers cause paw irritation if dogs walk through fresh application.
- Truly chloride-free: Safe Paw, Paw Thaw, Pet Friendly Ice Melter Plus (crystalline amide / glycol formulations)
- "Pet-safe" chloride blends: less harmful than straight rock salt but still cause irritation
- After any winter walk: wipe paws with a warm cloth
- Biggest risk: dehydration from ingestion (dogs lick salty paws) — keep fresh water available
Questions, answered.
Why doesn't my rock salt work in cold snaps?
Sodium chloride brine refreezes below -10 °C. If your overnight temperatures drop into -15 to -25 °C range (most of Canada in January), you need calcium chloride or magnesium chloride. Keep a 20 kg bag of CaCl₂ in the garage for cold-snap weeks.
Is calcium chloride safe around concrete?
Yes for concrete older than 12 months. No for new concrete — wait one full freeze-thaw season before applying any chloride de-icer. Sealed concrete tolerates de-icers better than unsealed.
What's the safest de-icer for dogs?
Potassium chloride and CMA are the two pet-safer options. They're more expensive and less effective in deep cold, but they prevent the paw-irritation and stomach issues caused by chloride salts.
How much salt or ice melt do I need for a season?
A typical suburban driveway + walkway = 25–40 kg of rock salt per season, applied every 3rd or 4th storm. Replace with 8–15 kg of calcium chloride during deep-cold weeks. Buy 1×50 kg bag of rock salt and 1×25 kg bag of calcium chloride at season start.