Now that winter is approaching, it’s better to be prepared now rather than later. It reminds me of the time I moved from Florida to upstate New York. I was wholly unprepared for what seemed to be a new ice age! By the end of November, when the first blizzard hit, not a single snow blower could be found for purchase locally, and all the contract plow operators were already booked for the season. Needless to say, I got quite a bit of exercise that winter…and a little pain too.
But the reason for my post is obviously geared toward concrete, and I want to share a few pointers with regards to snow removal, de-icing and care of exterior concrete. It is still fresh in my head as we completed a job a few weeks ago, with a decorative overlay to restore a concrete slab that had been through some serious winter torture. The maintenance people had used an enormous amount of rock salt and ice chippers to control the amount of snow and ice on the concrete. It did some serious damage, with much of the surface flaking off. The slab in question was a raised balcony and replacement would be an extremely difficult, messy and expensive option. Luckily we were able to restore it to like new and give it a decorative finish with a polymer cement overlay, but the owners were given a little instruction to prevent their maintenance staff from causing them further grief.
In case you missed my article on “Concrete Problems and Causes” I will paraphrase the section on the use of de-icing salts…
Concrete that is subjected to use of deicing salts combined with freeze-thaw conditions are prone to scaling. The National Research Council’s Strategic Highway Research Program tested deicing salts to see how they would etch and destroy concrete. The tests were interesting. It appears that magnesium chloride did the least amount of damage. Calcium chloride caused 26 times more damage to the concrete than magnesium chloride. Regular rock salt, sodium chloride, caused an astonishing 63 times more damage. If the tests were accurate, it appears that it may be worth the extra money to purchase and use magnesium chloride. Even still, your driveway will track rock salt from the roads, and it will concentrate in your garage where the snow/salt slurry collects and evaporates.
It is this reason why we see many untreated garage floors up north here that have scaled concrete floors. This is the perfect reason to have us install an epoxy floor in your garage. It is impervious to salt damage, makes it very easy to clean, and will keep your garage floor in great looking condition for many years.
Decorative concrete is not as prone to scaling from the freeze thaw/salt relationship generally because the project is finished off with an acrylic sealer. The sealer keeps the salts from penetrating the surface and becoming a problem. This is just one of the reasons exterior decorative concrete should be resealed every three years. So, the type of salt used on decorative finishes is not as much an issue as it is on unsealed concrete.
Snow removal on decorative concrete must be done without the use of metal blades. That includes metal snow shovels, ice picks and chippers, metal bladed snow throwers, and steel plows. Use a plastic show shovel or a snow blower with rubber blade. Contact your snow removal contractor and make sure they are using a urethane blade guard on their plow if you have decorative concrete on your driveway. Use of de-icing agents rather ice chippers or picks is a must.
You might not notice when grey concrete has minor imperfections or is scratched and abraded. On decorative concrete you will I can guarantee that. How bad will be determined by the process; whether color hardener or integral color was used, or if the surface was stained. You may not notice it as much if integral color was used because color will be present throughout the concrete, but with color hardener or stains, the color is only present on the surface, so once it’s worn off, it will become unattractive pretty quick. Even with integral coloring, it will be noticeable because when the surface becomes abraded the sealer is removed and the concrete will take on a lighter appearance than the surrounding concrete. This is because the sealer will darken the concrete when applied, much like it does when it gets wet.
So, the bottom line is take good care of your concrete and it will last a long time. If you don’t I have a good feeling you and I will be meeting for a quote next spring. While we at Abstract Concrete don’t ever turn down the opportunity for work, we would much prefer not to do repair work…you already paid for your decorative treatment the first time.