“That salt is for wussies.”
“What?"
”I said that white stuff is for wussies. Get some manly rock salt, boy!”
At that point, I realized I was looking over 5 palates of Morton Salt bags at a friend from grade school, Steve. I haven’t seen him for 20 years. He had 2 yellow bags of Morton Rock Salt loaded into his cart, and I had 2 white bags of Morton Safe-T-Salt loaded into mine. Then I wondered, does Steve know something I don’t know? So I did some research…
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How do the different bags of Morton Salt differ? There are 3 kinds of Morton Salt sold at local home stores…
#3) The “total wussy” green bag of salt is a mix of mostly sodium chloride (NaCl), but also has some “balancing” ingredients such as potassium chloride (KCl) and urea (NH2)2CO that make it easier on the plants and dogs in your yard. Yes the stuff that makes our urine smell. Doesn’t smell by itself, but when mixed with water it gives off ammonia gas, thus the stinky urine my wife always yells at me for leaving in the toilet. Urea and potassium chloride are also fertilizers. This total wussy salt also has a little hydroxyethyl cellulose and calcium silicate in it. They say it is a “secret blend” on the bag, but I pulled the MSDS safety/hazard sheet on the product for this teaching.
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So what would make the best salt to break through the ice dams on the roof of the house currently?
Probably the one that melts ice best, but doesn’t bore a hole in the concrete or the shingles at the same time. One that doesn’t kill everything that it contacts. One that works well in cold weather like we are having here in the great state of MN. That seems like an appropriate list of pros/cons for salt. So let’s compare these 3 and see if Steve was right…
Well, let’s look at the melting capability first, because that is why I’m putting salt in nylons up on my 2nd story roof. When you add salt to water, you introduce dissolved foreign particles into the water. The freezing point of water becomes lower as more particles are added until the point where the salt stops dissolving. For a solution of sodium chloride (NaCl) in water, this temperature is -21°C (-6°F) under controlled lab conditions. In the real world, on a real sidewalk, sodium chloride can melt ice only down to about -9°C (15°F). However as we have seen above, sodium chloride isn't the only salt used for de-icing, nor is it necessarily the best choice. Sodium chloride dissolves into two types of particles: one sodium ion and one chloride ion per sodium chloride 'molecule'. A compound that yields more ions into a water solution would lower the freezing point of water more than sodium chloride. For example, every molecule of calcium chloride (CaCl2) dissolves into three ions (one of calcium and two of chloride) and lowers the freezing point of water to about -29°C (-20°F) more than sodium chloride. So from a melting standpoint, calcium chloride (the “wussy” white bag) wins battle #1.
Wussy 1 : Manly 0
Now lets look at the major con to different Morton salt formulations, their corrosive properties. There is no question that sodium chloride (the manly yellow bag) is corrosive to concrete and any vegetation that exists in hibernation under the snow cover. Calcium chloride is not without its corrosive properties, but it is significantly milder than sodium chloride. So the yellow “manly” bag wins for manly corrosion, but loses for preserving the concrete that keeps your house standing straight and sidewalks from crumbling. I think that means another point for the wussy white bag. Depends on what you want to do with the salt though. I was not interested in boring drainage holes in the concrete, so I’ll give the point to…
Wussy 2 : Manly 0
How about pricing? Well, a 10 lb bag of the manly yellow stuff costs $5.29 compared to $11 for the wussy white bag, and $13 for the eco-friendly green bag. So there is no question about it, the manly yellow bag wins this category hands-down.
Wussy 2 : Manly 1
Last category I have to include is “other performance characteristics”. When the temperature drops below zero, calcium chloride (the wussy salt) attracts moisture and can make things more slippery than the sodium chloride does, which tends to dry a little better. So unfortunately, this sub-category goes to the yellow manly sodium chloride bag. And yes, it is generous of me to give a whole point for this category, but Steve’s a good guy.
Wussy 2 : Manly 2
So we tied. Wussy 2 : Manly 2. I guess here’s how I would summarize it. If you are looking for something that will perform well in the single digits and sub-zero realm, want to be less corrosive on the concrete, gutters, plants, don’t mind 2x the price, and can handle a little less drying property when the temps are extremely cold, the white calcium chloride “wussy” salt is the one to go with. If you want the cheapest bang for your buck, don’t care about the plants/gutters/concrete as much, and don’t expect the temperature to sit in the single digits or lower, go with the “manly” yellow bag. Now I just gotta find Steve’s email address somewhere so I can let him know what I found out. Maybe he knew this all along. The yellow bag is definitely more “manly.” Just not what I needed to take care of the ice dams on my roof.
Which, by the way are well solved by laying nylons filled with salt perpendicular to the gutters across them to form channels in the ice dam that will last most of the season in the nylon. That’s what hangs over my shoulders in the picture above. Jessie thinks they look like something else that she can’t quite put her finger on yet. There’s more info on ice dams here.
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