Rock salt, also known as (a.k.a.) sodium chloride, road salt or halite, is the least expensive of the ice melters. It is effective down to about plus 20° F. When it’s colder than that, salt just lays there. It can damage concrete, grass, plants and wood decks. If concrete is less than one year old, rock salt is not recommended.

Magnesium Chloride, a.k.a. Super Rid Ice®, works down to minus 13° . This is another fertilizer product, so it avoids some of the negative associated with rock salt.

Calcium Chloride, which we sell as Ice Warrior®, is the gold standard of ice melters. It works down to 25°  below zero and is known to be quite safe around plants, decks and concrete. This is the one generally recommended for ice build-ups on roofs and in gutters.

How they work

Many people think the object of using ice melters is to MELT ALL THE ICE.
Well, they’re wrong. Ideally, the ice melter will melt through the ice, down to the concrete or other solid surface, where it breaks the bond between the pavement and the ice so that the ice can be shoveled away.

Ice melters work poorly on gravel walks and drives, because there is no pavement surface where they can work. They tend to go through the ice and into the gravel without having  much effect.

Pellets or flakes? The pellet is the most efficient shape for burrowing down to the pavement surface quickly. Once it’s at the pavement surface, it dissolves and spreads out. This is exactly what you want.

Liquid Calcium Chloride can be very effective if it is sprayed on the pavement before the snow falls. This can keep the snow and ice from bonding to the surface, making it very easy to shovel away.

Combinations such as salt with calcium chloride can be effective and economical. The calcium chloride generates
heat as it melts the ice, allowing the rock salt to work better and faster even in very cold conditions. Other combinations work in similar ways.