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Spring has arrived and along with it come the ugly results of the winter damage that has been done to the concrete of your garage floor. This is typically due to the deicing fluids and road salts that have been deposited on it over the winter. Now is the time to take inventory of any harmful salt stains that need to be removed as well as spalling that needs repair.
The best plan of action is to understand what causes this winter damage and then take the steps to stop it from progressing We’ll discuss the best way to clean up or repair your concrete from the damage left behind as well as how to protect your garage floor.
How deicing fluids damage your garage floor
When it snows, road crews typically use various forms of liquid magnesium and calcium chloride (road salt) to de-ice the roads. The application of these products essentially melts the ice and snow with the intention of keeping it from refreezing. The problem with this is that it tends to attach itself to the bottom of your vehicle where it eventually gets deposited onto your garage floor.
These deicers create a liquid brine that seeps into the pores of your bare concrete instead of freezing on top. Once this brine is diluted enough to become ineffective or when the temperatures drop low enough, it refreezes inside the pores of your concrete, thus expanding and slowly breaking it apart. This cycle can happen over and over again during the winter. The result of this broken concrete is what’s known as spalling.
Even if road deicers are not used in your town, water that works its way into a more porous garage floor can still freeze overnight and slowly cause the same kind of damage.
Another nasty side effect is subflorescence. This is caused when the moisture in your garage floor finally evaporates and all the salt left behind recrystallizes in the pores of the concrete. This causes areas of your concrete to flake off or spall. It also leaves behind those ugly white stains on the floor.
Repairing winter damage and salt stains
The first thing you want to do is clean your entire garage floor to expose any damage and highlight any salt stains that you may have. Once clean, removing the salt stains off your garage floor isn’t too difficult if you use some elbow grease and know what to use. Rinsing with just water will not work effectively. The key is to mix up a solution of 1 gallon of warm water to 1 cup of vinegar with a squirt of dish soap.
Pour the solution onto the stains and scrub with a stiff deck brush. Use a mop or wet vac to remove the residue first and then rinse liberally with water. The reason for mopping or using the wet vac (preferred method) is to prevent the salty solution from being dispersed back into the pores of the concrete when you rinse it. This is why just rinsing with warm water to remove salt is not very effective. For particularly tough salt stains it may require another application or two.
As far as good aftermarket products, Salt-Away has been known to work well. You can find it here at Amazon.
It’s very popular for use with marine products and is also used to remove salt from concrete, brick, and masonry as well. It needs to be applied and the residue removed in the same manner as the vinegar solution.
For the most stubborn salt stains, you can use a mild solution of hydrochloric acid. Mix 1 part acid to 20 parts water. This is actually a very mild concrete etch. We have instructions on how to mix and neutralize acid solutions here.
As a note, pressure washers are not always successful in removing salt stains. They have a tendency of driving the salty solution deeper into the concrete just to reappear again.
Once the salt is removed, now is the time to repair any pitting or spalling that may have occurred from the deicing fluids. Polymer modified cements work well for this. They bond much better than regular cement and create a stronger finish that can be feathered much thinner. Regular cement patch will not adhere well to the surface and can chip or break away. You can learn more about repairing spalling and pitting here.
Protect your garage floor from winter
Once you are satisfied with the outcome of cleaning and repairing your garage floor, the next step is to protect it from winter damage in the future.
The least expensive method is to apply a penetrating sealer that blocks deicing fluids from penetrating into the concrete to begin with. You can also use containment floor mats, or apply a good topical sealer.
Also, try to be diligent about cleaning the floor after the latest storm has past to remove any corrosive debris. For more information, you can read about the multiple ways to winterize your garage floor here.
Once you restore your garage floor from winter damage and take steps to prevent it from recurring in the future, you will no longer have to fret over the anticipation of what spring reveals with your concrete garage floor.
What product can be used to remove the micro salts, I have heard that if not removed they will cause premature failure of Epoxy coatings, is this true?
Hello Jim. If you are referring to removing the salts before application of epoxy, a proper acid etch that is neutralized and thoroughly rinsed removes the salts that can inhibit a good bond. Better yet, grinding does this as well as removing all laitance from the surface of the concrete which provides the best bond for epoxy.
If you are referring to after application, a quality epoxy coating is impervious to all salts. Depending on the coating, road salts may cause a slight discoloring if allowed to dry and set for a long period for the cheaper DIY kits. Mild soap and warm water do wonders for cleaning all residue from an epoxy floor. We also like to use a mild solution of Simple Green as well.
After I washed the epoxy garage floor, a section exposed to the sun when the garage door is open (to the south) lost it’s shiny surface. Not sure why, but I would like to restore that surface. What can I do?
There isn’t a lot you can do to restore gloss John, other than applying a new coat. If you have a clear coat, then the process is fairly easy. It just requires roughing up the surface with 100 grit sandpaper and then apply a new clear coat. You are best off doing the entire floor instead of just one area however. The reason is that epoxy does not work like latex paint and blend right in. New areas are obvious and look much shinier than the surrounding areas. Plus, many times the roller edges show where the new coat meets the old.
Can I repaint a section if I am not satisfied, with the same epoxy paint , it has paintchips in it?
It depends Colleen. Do you have a 1-part epoxy paint or an actual 2-part epoxy coating? Epoxy paint can be repainted over areas and it’s not very noticeable. However, with true 2-part epoxy coatings any recoated sections will stand out and look different.
My concern is recurring white stains. My understanding is that road salt and the like, first penetrate into the concrete. Then, over time, that residue is slowly forced upward (time and again) and combined with C0-2 creates the white haze. Hence, you can clean all you want, but if there is still salt within the concrete, you essentially get nowhere. I am looking for a product or home remedy that does more than clean the top of the concrete but instead seeps into the concrete (as the salt has done), and neutralizes it so it doesn’t eventually rise to the surface and create the white powdery film/haze. Then I’ll clean the surface when I know the white stuff won’t return. Is my thinking correct on this, and what would you suggest?
Hi Tom. If the concrete has been subjected to years of road salt, then yes, it can be very difficult to get all of it out of the concrete. It’s only forced up if the slab is below grade and you have moisture issues. However, if the slab gets wet from wet cars and such, the water that the concrete absorbs at the surface will work it’s way back to the top when the right atmospheric conditions exist. In either case, when the moisture gets to the top it will evaporate and deposit the salt crystals that it carried with it from within the concrete onto the surface. This is the white haze you refer to.
One of the keys that we mention in the article is to use a good shop vac to suck up the solution on the concrete. Keep adding solution so that the surface stays wet and then suck it up. This helps to draw the salt out. It can take many repeated applications to draw most of it out. Once you do, we highly recommend applying at the minimum a densifier with siliconate sealer added to help resist the salt intrusion to begin with. A coating would stop it all together.
I suppose a little more info would have been good- I just put in a very nice (and expensive) concrete (brick sized) paver patio, 10′ x 10′. I was salting over a narrow pathway on that. I put first, regular road salt and then “Road Runner” which I thought was less caustic. Maybe 3 applications total. When I noticed I had a problem, I cleaned everything off with a wire brush, then bristle brush w/ soap & water, but then the haze returns over time (this is not a large polished concrete slab and there is pervious grout between the pavers). So yes, it gets wet routinely with the rain (no roof). I guess the removal of rinse water is important, so I’ll do that a few times and hope the re-emerging stains begin to stop reappearing. Thanks for reading.
Ahh… that makes sense then. Yes, use a good wet shop vac to remove the neutralizing solution, rinse, and then vac again.