Types of Ice Melt
All deicers work by lowering the freezing point of water, but they differ in effective temperature range, surface safety, environmental impact, and cost. Rock salt (sodium chloride) is the cheapest but damages concrete and kills plants. Calcium chloride works to minus 25 degrees but costs 3 to 4 times more. Magnesium chloride is the gentlest on concrete and vegetation but only effective to about 5 degrees Fahrenheit.
Ice Melt Comparison
| Type | Effective Down To | Cost per lb | Concrete Safe | Pet Safe |
|---|---|---|---|---|
| Rock Salt (NaCl) | 15 to 20 F | $0.10 to $0.20 | No (corrodes rebar) | No (paw irritant) |
| Calcium Chloride (CaCl2) | Minus 25 F | $0.50 to $0.80 | Moderate | No (skin irritant) |
| Magnesium Chloride (MgCl2) | 5 F | $0.40 to $0.60 | Yes (gentlest option) | Moderate |
| Potassium Chloride (KCl) | 12 F | $0.30 to $0.50 | Yes | Yes |
| Urea | 15 F | $0.25 to $0.40 | Yes | Yes (lawn fertilizer) |
Application Tips
Apply deicer before the storm when possible. A thin layer prevents ice from bonding to the surface, making shoveling easier and reducing the total amount of product needed. Most homeowners over-apply by 2 to 3 times the effective rate. For rock salt, 1 to 2 tablespoons per square foot is enough. More doesn’t melt faster; it just damages more.
