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Clear Your Walks, Protect the Environment

By Robert G. Wilkin, P.E.

There are a number of materials to put on walkways to melt snow and ice.  The old standby is sodium chloride (NaCl), also known as rock salt.  It is a highly corrosive material and its effect on concrete sidewalks and the environment makes it the least sustainable choice available and it’s only effective to 15°F.  The main advantage is that it’s cheap.  Calcium chloride is another readily available salt that is less corrosive to concrete but still is harmful to the environment.

There are greener deicers that will not damage walkways or the environment.  Green alternatives can keep walkways and steps clear at lower temperatures than salt, and in some cases, for just a few cents more.

ENVIRONMENTALLY FRIENDLY DEICERS

If you choose to go the chemical route, find products that minimize corrosion to concrete and have a mild impact on the environment, leave a residual (this keeps melted ice and snow from refreezing), and stores well without caking or bricking.  It’s a good idea to ask for independent lab results or patent information to evaluate the manufacturer’s claims.

One example is an organic substance, GeoMelt USA by SNI Solutions, is made from sugar beet processed byproducts.  It can increase the efficacy of rock salt, melting ice in -25°F or -30°F temperatures.  GeoMelt also allows users to apply about 25-30% less of both substances, leading to less corrosion of the concrete and metals such as steel.

Also, urea is a chemical found in most fertilizer formulas, made from ammonia and carbon dioxide.  It can be mixed with salt to lower the cost.

SALT-FREE DEICERS

There are blends available that don’t include any salt or other chlorides, making them safer for the environment and for use on concrete. 

Calcium magnesium acetate (CMA) is a salt-free melting agent made from limestone and acetic acid.  It causes less damage to concrete or plants and can be used as a salt alternative in environmentally sensitive areas.

Although not widely known, alfalfa meal, usually used as a fertilizer, is an environmentally friendly way to clear your walk.   It is high in nitrogen content that helps melt the ice.

Sugar beets are also now being used as deicers.  They are 100% organic and much less corrosive than salt.  Sugar beets can be used independently or mixed with different concentrations of salt; they help reduce the clumping and freezing of salt piles.

ALTERNATIVES TO CHEMICALS

Instead of applying chemicals, use heat.  Snow-melting systems can last many years; 3-5 years for a portable heated walkway mat and 20 or more for an underground radiant heat system.  These portable systems eliminate the majority of labor associated with clearing snow.  

Portable heated walkway mats, such as HeatTrak, can be switched on before the snow falls or be turned on as needed.  They can also easily roll up and be stored until next winter.  This is a good option for walkways or stairs.

Radiant heat, either electric or hot water types, must be set into the concrete so it can heat from below and is also an option for driveways.  Installation and operational costs for a radiant heat system can be high, but it prevents the need to use salt or other chemicals where the heat system is installed.

IN CONCLUSION

While rock salt is cheap, it harms the environment, deteriorates concrete, and for just a little more money there are alternatives.  Be sure to read the labels on deicer chemicals you buy because some mixtures are mostly rock salt.  Adding heated walks in critical areas limits supervision and maintenance work, but is significantly more costly than chemicals.