Back in ye olden days regular salt or sodium chloride was the usual choice for deicing roads and sidewalks. Now there are several deicer options, so you can choose the best deicer for your situation. The Transportation Research Board offers a tool to help you compare 42 deicer options based on price, environmental impact, temperature limit for melting snow or ice, and the infrastructure needed to use the product. For personal home or business use, you'll probably see only a few different products on the market, so here's a summary of some of the pros and cons of the common deicers:
sodium chloride (rock salt or halite)
Sodium chloride is inexpensive and helps keep moisture from accumulating on roads and walkways, but it is not an effective deicer at low temperatures [only good down to -9°C (15°F)], damages concrete, poisons the soil, and can kill plants and harm pets.
calcium chloride
Calcium chloride works at very low temperatures and isn't as damaging to the soil and vegetation as sodium chloride, though it costs a bit more and may damage concrete. Calcium chloride attracts moisture, so it won't keep surfaces as dry as many other products. On the other hand, attracting moisture can be a good quality since calcium chloride releases heat when it reacts with water, so it can melt snow and ice on contact. All deicers must be in solution (liquid) in order to start working; calcium chloride can attract its own solvent. Magnesium chloride can do this too, though it isn't used as commonly as a deicer.
This is an amide/glycol mixture rather than a salt. It is supposed to be safer for plants and pets than salt-based deicers, though I don't know much about it otherwise, except that it is more expensive than salt.
potassium chloride
Potassium chloride doesn't work at extremely low temperatures and may cost a little more than sodium chloride, but it is relatively kind to vegetation and concrete.
corn-based products
These products (e.g., Safe Walk) contain chlorides and work in very low temperatures, yet are supposed to be safe for yards and pets. They are expensive.
CMA or calcium magnesium acetate
CMA is safe for concrete and plants, but it is only good down to the same temperature as sodium chloride. CMA is better at preventing water from re-freezing than at melting snow and ice. CMA tends to leave a slush, which may be undesirable for sidewalks or driveways.
Deicer Summary
As you would imagine, calcium chloride is a popular low-temperature deicer. Potassium chloride is a popular warmer-winter choice. Many deicers are mixtures of different salts, so that you get some of the advantages and disadvantages of each chemical.
Comments
I used only Safe Paw liberally on my sidewalk last winter, and I still got some grass kill. So this winter I’m trying to reduce the amount I use. I sand the sidewalk sometimes instead of salting, if it’s only a thin layer of ice.
I’ve heard some cities are experimenting with “liquid salt”- I presume what they’re doing is applying a heated saturated solution. This would apply the salt more uniformly, allowing them to use less. I might try that on my sidewalk. I’d also want to use a salt that has a steep solubility curve, to minimize the amount of water I’d have to use.
There is a new product on the market in Canada..called Ecotraction. It is volcanic sand/ash and does not need to be combined with sand as it has a low freezing temperature. I use it on my concrete driveway as very slippery. Need to clear snow first and a bit dirty, but works.
My name is Steve with the Safe Paw Ice Melting company. Thanks for this wonderful Article explaining to people the dangers of Salt. Sorry about your grass, I am sure you noticed it came back to life shortly after spring. It is merely a temporary issue from the Nitrate inhibitors. If too much Safe Paw is applied it makes it hard for the plant to take up certain nutrients, but this is quickly resolved after a good rainfall or two and sunlight. Hope all is well.
Steve, You are employed by Safe Paw, is that correct?
This past winter we had heavy snow in the Mid-Atlantic region. An eco-friendly deicer was sprinkled on my concrete stairs. The snow on the stairs wasn’t completely removed, there was still a good layer of snow on the stairs. I’m also aware that how the concrete was installed can make a difference in whether or not there would be damage to the concrete. (My guess is that my concrete wasn’t of good quality.) My home is 4 years old. Could a one time application of deicer cause damage to concrete?
Anne, some of your facts regarding the effect of deicers on concrete are incorrect. You state that CMA is safe for concrte. However, CMA (calcium magnesium acetate) or any magnesium based deicing salt can chemically attack concrete. You also state that sodium chloride damages concrete. If the concrete is of good quality, and was properly finished and cured, then sodium chloride will not harm the concrete.
Over time, the use of chloride based deicing salts can cause corrosion of the reinforcing steel within the concrete (mostly a concern in bridge decks). Studies were performed with CMA to show that it won’t cause corrosion of the reinforcing steel of concrete and hence was claimed to be safe for use on concrete. However, since that time numerous studies have been performed showing that the use of CMA on concrete will deteriorate the concrete.
Safe Paws is NOT safe for lawns. I used it in Chicago and it killed my lawn all along my driveway. Since its so harmful to plants, I am not too sure it really is safe for pets.
I never use deicers – clear the worst by hand and then just use sharp sand or another crushed material like pumice if locally cheap – all you need is a grip to prevent slippage – no need to deice and have it refreeze again!
Oh and driving… going slowly and anticipating means no slips even with summer tyres!
@ Nick, Nick your information is wrong about CMA (Calcium magnesium acetate) CMA is the only deicer you can use on new concrete all other deicers you usue you have to wait a year before using any kind of deicer. CMA has be and for many years been studied and proven to be the safest deicer we have. The Salt Institute from Alexandria, Virginia has done research, Cryotech makes it and does contineous research on it and its effects, and actually CMA came from the DOT for deicing on bridges and in no salt zones all over the US. I will say this is why CMA is less corrosive than tap water, and CMA is proven to reduce the corrosiveness of Chlorides, CMA is biodegradable and if it gets on your lawn it is no different then liming your lawn CMA, CMA biodegrades to carbon dioxide and water while the calcium and magnesium increase soil permeability, it is essentially non-toxic to aquatic species. Nick you claimed that CMA is not safe on concrete that is false information, by using CMA on your concrete, pavers whatever it may be it is actually proven better than not using anything the reason being is the freeze thaw cycle with CMA down that freeze thaw cycle is not as big as the water that mets off the ice and re freezes, now when you add maybe ethylene glycol (which is in Safe Paw, and anti-freeze in cars…), Urea ( Fertilizers), Calcium Chloride, and Sodium Chloride your freeze thaw cycle is a lot bigger causing spalling and crack in your concrete, popping pavers and damaging your concrete no matter how well you lay your concrete.
** I want to encourage people to read what chemicals are in the deicer products before you buy them. There is no law in labeling so comapines can say “safe for pets” when actaully it is not safe at all for them. It can burn their paws, and if they drink puddles from melted ice/snow from the chemical it can burn and harm them from the inside. Know your chemicals and what you are putting down and how much material you are putting down. Be Smart about what you are buying and don’t buy into salesman BS. Stay safe in the winter season everyone!
Reading about the bridges and just wondering about how they mix this stuff with concrete in the winter to keep it from freezing. naybe that corodes the rebar in the bridges as well