Is Ice Melt Bad For Concrete, Sidewalks, and Driveways?

Is Ice Melt Bad For Concrete, Sidewalks, and Driveways

Rock salt and ice melt is designed to keep surfaces free of ice, but it may cause damage to the very surfaces that you are applying it to.  If you have taken a few minutes to search online about whether ice melt is bad for concrete, sidewalks, and driveways and you are more confused than before you started you are not alone.  There is a lot of conflicting information from companies selling ice melt, others selling concrete and sealers, and lawn and garden professionals that switch to helping clients maintaining a snow free sidewalk and driveway during the winter and want to be hired to regularly put down ice melt or rock salt.

The following article is going to cover a few best practices and things to be aware of when using ice melt on concrete and ways to help minimize damage to your concrete.

Ice Melt Works But Can Have Consequences

In general rock salt will damage your concrete and similarly most of the ice melt products available on the market can as well.  This damage is created not so much from the actual products themselves but that they encourage the freeze / thaw cycle that can lead to water damaging the outer crust of your concrete sidewalks and driveway.  Therefore, many products that advertise safe to be used on concrete will still result in a damaged surface due to the freeze / thaw cycle.

You must weigh the pros and cons of using a deicer so that you can safely walk around your home and drive your car in and out of the driveway against the possible damage that can be inflicted on these surfaces.

The Freeze and Thaw Cycle Damages Concrete

The biggest risk to damaging your concrete during the cold winter months is the freezing and thawing cycle that occurs over prolonged extreme low temperatures.  As the water builds up on the surface it gets absorbed into the top layer of the concrete.  This porous surface is likely to capture more water when you use a deicer since by their nature, they are designed to turn the ice to water by heating up.  This water that gets absorbed then refreezes when the chemical heat dissipates, and the cold temperatures persist.

The frozen water in the concrete expands and the pressure eventually is too much for the surface layer of the concrete causing it to become brittle, resulting in what is called scaling.  Scaling looks like a series of pock marks in the concrete surface in and unbelievably bad spots will look like the whole outer shell of the concrete has withered away.

The water being absorbed by the concrete is not the fault of the deicer that you are using, it is a simple fact of science and part of the nature of the porous concrete.

Break the Freeze / Thaw Cycle

As mentioned above there is nothing you can do to eliminate the water from absorbing into the concrete, but your alternative is not addressing the ice leaving an unsafe environment to walk or drive on.  The answer is to use a deicer for the layer of ice directly on the concrete and then once it has turned to slush and is breaking up to remove as much of the ice and slush as possible from your driveway or sidewalks.  Use a snow shovel or a large push broom to remove the icy slush from the surface so the air and sun can dry the ground before refreezing.

How to Prevent Concrete Damage

  • A highly graded and exceptionally durable concrete mix should be used. Hiring a professional concrete company to poor and grade your concrete is particularly important when you reside in a very cold climate.  Amateur concrete jobs tend to have the shortest lifespans in harsh weather climate conditions.
  • Ensure that the concrete has an adequate slope, so it properly drains and does not pool up in specific spots on the slab. If there is any pooling it will increase the water absorption in those areas and the concrete will fail their first.
  • Make sure that the concrete is finished properly and cured for the proper amount of time. Use a concrete sealer to give your concrete driveways and sidewalks the longest lifespan and be ready to repair spots that get damaged during the warm months of the year.

Which Ice Melts To Use On Concrete, Sidewalks, and Driveways

  1. The most conservative approach while still getting the benefits of brine to thaw the ice is to mix sand and a little bit of salt together and then apply it. The sand will give you some traction to walk or drive on and the rock salt will create a brine and begin to break up the ice.
  2. Calcium chloride one of the fastest acting ice melts is considered the safest of the ice melt products for use on concrete and the surrounding plants. It can be used both directly on the ice to address a frozen area or to be used in a preventive method to be laid down prior to expecting ice.
  3. Magnesium chloride is the most damaging of the ice melt products for using on concrete. Magnesium chloride is on the list of chemicals to avoid placing on concrete surfaces by the American Concrete Institute. You will find many people talking about how magnesium chloride is safe to use on concrete and if you use the product and clean the surface after a storm you will likely not encounter any issues.
  4. However, consider a ice melt that contains potassium chloride as that will give you more time to get out and shovel or sweep off the ice and water from the concrete surfaces. While not getting as hot as calcium chloride potassium chloride stays warm longer.

According to using deicing on pervious concrete is acceptable:

Chemical Usage Deicing chemicals used to maintain an ice-free, safe pavement surfaces for dense pavements may be used on pervious pavements; however, in many cases deicers may not be required to maintain a slip resistant surface. Snow fall followed by thawing temperatures allows snow melt to pass through the pavement so rapidly that liquid water is not available at the pavement surface to be refrozen as an ice coating. Ice-free pavement surfaces aid safety for pedestrians and vehicles. With appropriate plowing and limited use of deicers, moisture is removed from the pavement surface, again preventing moisture from freezing at the surface and causing icy conditions. As any melting from the use of deicers occurs, the melt passes downward into the pavement and in many cases leaves behind some un-dissolved deicer making it available to future snow and ice events.

Alternatives to Ice Melt For Use On Concrete, Sidewalks, and Driveways

  • Sand – This is the preferred method for a zero salt or chemical approach to creating a safe surface to walk or drive on. Use a play sand or a coarse sand from the hardware store and apply onto the surface of the ice.
  • Birdseed – Similar to sand birdseed when applied to the top layer of snow or ice will give your feet something to gain a little traction with and prevent you from slipping while walking or driving. It is all natural and the local birds won’t mind getting a snack or two during the cold winter months.

Things to Remember When De-icing Concrete, Sidewalks, and Driveways

Wash the concrete driveway down and brush it off after the storm has passed to keep the concrete driveway clean.  This is the best way to prevent the concrete from being damaged by any residual chemicals that may be in the ice melt that you use.  Once the deicer has worked do your best to remove the icy slush so that the concrete can dry out.This will reduce the amount of moisture in the concrete before it has a chance to refreeze and cause serious damage.

While a surface sealer may be harmed by the chemical in a deicer, the real damage that you will encounter with ice melt’s is all due to the thaw / freeze cycle that occurs in cold climates.  Keep the surfaces dry after a storm and you will be well on your way to avoiding any problems using an ice melt product.