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Do you sweep or clean the concrete of your garage floor only to have it feeling gritty and dusty the next day? Even after washing it down, can you can run your fingers over the concrete once it is dry and get a white, dusty film on your fingertips? If so, you may have a problem with concrete dusting.
The good news is that dusting of a garage floor can be reduced in many cases and sometimes stopped completely depending on the severity and the solutions that are applied.
What is concrete dusting and what causes it?
Dusting is the white chalking and/or powdering of concrete at the surface. It is primarily caused by the slow disintegration of a weak top layer of concrete. Foot traffic, cars, and even cleaning can enhance the problem.
There are many reasons for this weakened layer of concrete. It can range from poor mixing at the concrete plant, excess clay or silt in the concrete mix, old age of the concrete, or even insufficient curing.
The most common reason, however, is excess bleed water at the surface. If there is too much water in the concrete mix, this water will rise to the surface during the finishing process (troweling). This bleed water can carry finer particles and cement to the surface, forming a weak layer of concrete at the upper most top of the slab.
This surface laitance is actually a porous layer of softer concrete that slowly breaks down, thus creating the white powdery surface. In some cases, the surface can be so soft that it can easily be gouged with a sharp screwdriver or nail.
In addition, this same condition can be caused when water is added to the surface during the finishing process. This is commonly done by less experienced and DIY concrete finishers in a last-ditch effort to create a smooth troweled surface.
Unfortunately, sweeping and even pressure washing of the concrete never seems to get it completely clean since the surface is in a constant state of disintegration.
If left untreated, this fine concrete dust can become extremely annoying as it finds its way onto the surface of cars, work benches, laundry machines, and anything else kept in the garage. It can also be tracked into the house on the bottom of your shoes.
How to stop a dusting garage floor
There are a few solutions for stopping or reducing dusting of your garage floor. However, how effective they are is dependent upon the severity of the dusting to begin with.
For light dusting, the easiest solution in many cases is to apply a quality densifier. Typically used for warehouse floors and polishing concrete, they have other uses as well, including the reduction of concrete dusting.
Densifiers are non-film forming and do not change the look of concrete. They work by penetrating into the upper layers of the concrete surface to create a chemical reaction with the minerals. This reaction forms a hard substance called calcium silicate hydrate (CHS) which fills many of the open pores and capillaries at the concrete surface.
The resulting reaction is reported by various manufacturers to increase the surface strength of concrete by 20% – 40%, depending on the initial condition of the concrete to begin with – and that is the odd paradox of a densifier.
The best way to explain it is like this. Densifiers tend to be most effective the better a concrete surface is and less effective the worse a concrete surface is. As a result, the worse the concrete dusting, the less effective a densifier will be. That is why they work best at reducing or stopping light dusting only.
Lithium based densifiers are the easiest to apply and typically the most effective. They are relatively inexpensive and all that is required is to clean the concrete before application.
One product that we highly recommend is PS104 by Concrete Sealers USA. It’s a lithium densifier with a siliconate sealer added.
Not only will it densify your garage floor to reduce or stop dusting, the added siliconate sealer will also seal the surface to protect it from water and salt damage as well.
You can check the latest price of PS104 here.
Check Price of PS104 – 1 Gallon
Check Price of PS104 – 5 Gallon
We also have an article that explains in more detail how a densifier with siliconate sealer works.
Another option for light to moderate dusting would be the application of an acrylic topical sealer.
Acrylic sealers are film forming and create a protective coating on top of the surface. This thin coating layer acts as a barrier over the concrete thus sealing in and stopping the dusting.
If the garage will encounter vehicle traffic, then our recommendation would be an MMA acrylic sealer.
This type of acrylic sealer is the most durable and will not suffer from hot tire pickup and will resist staining and chemicals much better than water-based and standard solvent-based acrylic sealers.
An epoxy floor coating or similar is another option to stop dusting of a garage floor. However, grinding of the concrete surface would be the required concrete prep when dusting is an issue.
The reason is that grinding will remove the excess laitance and thin layer of soft concrete at the surface. Acid etching will not.
If epoxy or a similar coating is applied to dusting concrete that was prepped only with acid etching, the epoxy will peel up at a later date, exposing a thin layer of concrete dust on the bottom of the epoxy.
Stopping moderate to severe concrete dusting
If the surface of your concrete is soft enough to easily gouge with a screwdriver or your dusting is more severe, then aggressive grinding, shot blasting, or scarification of the concrete surface is going to be required.
This type of aggressive mechanical process effectively removes the soft upper layers of concrete to expose the harder surface underneath. It also leaves the concrete with a very rough finish.
This leaves you with a couple of options. The first is to coat over the rougher finish with a thick, multi-layer commercial epoxy coating system.
The second option is to smooth out the surface of the concrete with less aggressive grinding stones. After that, you can then properly seal the concrete.
Final thoughts
Though concrete dusting can be a real nuisance in your garage, it doesn’t mean that you can’t tackle the issue with a little bit of DIY effort on your part.
Unless the dusting is moderate to severe, an application of a quality densifier, an acrylic sealer, or a garage floor coating system will usually get the job done.
If the dusting is severe or the concrete is so soft that it can be gouged fairly easily, then we recommend contacting a garage floor coating company or concrete grinding contractor to discuss your options.
Lastly, do not rely on a home improvement center to help solve your problem. They typically are not well educated on such topics and most do not carry the proper products to use.
Instead, we recommend contacting a quality vendor who specializes in concrete floor coating and sealing products to ask questions. Their knowledge and experience can help you to successfully stop concrete dusting of your garage floor.
We had a concrete patio poured over 2 months ago. We have a lot of dusting that we keep tracking into our home. It also cracked in 2 places. How do we deal with the dust?
Hi Rena. It sounds like your concrete contractor used too much water on the surface to finish the patio. The best way to stop the dust is to apply a solvent-based acrylic sealer. We highly recommend this product here. Before you apply an acrylic sealer, you will want to remove as much of the dusting surface as possible without having to grind. We recommend acid etching the surface and make sure to neutralize it properly. After it has been neutralized and rinsed, a pressure washer will help to remove the remaining dust. After it has thoroughly dried, you can then apply the acrylic sealer. Two coats should do it.
Will the PS104 do the job?
Yes, that will work as well. The PS104 is a densifier that has an additional siliconate sealer added. The densifier is what helps with the dusting and not so much the additional sealer. The PS103 is a densifier only. It has slightly more solids for densifying, but so much more that it will make that much of a difference.
Thank you so very much!
Our 1 yr old concrete, covered patio still has sanding, so we’ll try a densifier. But the color of the concrete is beige/ orange. Can we paint or stain it first, gray, then apply a densifier?
Hi Jim. Densifiers and other penetrating sealers can’t be applied to paint. The paint prevents them from penetrating into the concrete. True stains permanently stain the concrete and do not form a film on the surface like paint does. As a result, a densifier or penetrating sealer can be used. Keep in mind that penetrating sealers applied to stained concrete will not darken the stain and make it glossy. It will look just as it did before the densifier was applied.
Thanks. So I can stain, then densify- or densify then paint. What would last longest? Seems like a stain would, as I’ve seen painted concrete chip over time.
Stain is permanent, Jim. Keep in mind though, you can’t stain a beige colored concrete surface to gray. That’s not how stains work. Stains are translucent and the beige color will show through. You would need to use paint if you want a solid grey color.
Should the concrete company be responsible for the concrete dusting?
Hi Betty. In most cases for new concrete, the contractor is the one responsible. However, some exceptions can be written into the contract for things that cannot be controlled by the contractor such as unexpected weather (rain storm for example).
Hi we have had severe concrete dusting from the first week our driveway was poured. The concrete company and supplier have told us it is our fault because we started hosing it down throughout the day from 48 hours after pouring for 7 days as we thought this would give it strength. We are pretty sure it is not from this and more from the bleeding of the concrete when finishing. Love to hear your feedback.
Hi Angela. The method you used is very common and would not cause your slab to dust. There is abundant information available about wet curing concrete. The dusting you are experiencing would be caused from one or more of the reasons we describe above.
My new garage floor is only a few days old and is dusting. How long do I need to wait before applying anything to stop the dusting?
Hello Jeff. Concrete should not be dusting after only 3 days. It is still going through the initial curing process. We recommend that you contact the concrete contractor you used to discuss what is going on with your slab.
I have a similar situation where a 2 year old pour of a 20×20 outdoor basketball court keeps dusting. We painted with concrete paint and every last in lifted up. Contactor says normal to be patient, but now I’m also seeing long cracks. Would a stain rather than painting again be better? I tested some redwood stain, which is same color as patio, and it seems to be holding up so far.
Hi Brett. Dusting that is heavy enough to cause paint to peel up due to deterioration of the concrete (dusting) under the paint is not normal. That is heavy dusting. Unfortunately, the only way to rid yourself of the nuisance is to grind off the weak layer of laitance at the surface. The stain will lighten in color and go bare in spots due to the dusting and no coating product is going to adhere until the weak layer is removed.
We just had waterproofing done to our garage/basement floor. The contractor removed the concrete around the perimeter and put in a drain system and then poured new concrete. The new concrete is very rough and not smooth like the rest of the slab. The entire garage is covered with fine dust now that tracks in the house. I have vacuumed with a shop vac but this has not helped. What would you recommend? Should we do something to smooth out the new concrete with the existing concrete?
Hi Jared. From your description, the new perimeter concrete may have a thin layer of heavy laitance or weak concrete that is causing the dusting issue. Does the main slab dust at all and what kind of shape is it in? Has it been treated with any type of sealer?
The main slab doesn’t dust. I am not sure if it has been treated with a sealer. We just bought the house in December. I looked up “laitance” that you mentioned in your reply and the newly poured concrete looks like some of the pictures that came up on Google Images. The main slab is in fairly good condition. It is smooth and has some stains here or there but overall looks good.
OK, that helps. We would recommend that you lightly grind the surface of the new concrete to remove the excess laitance. Afterwards, treat it with a densifier sealer like what we recommend in the article. Doing this should heavily reduce if not eliminate the dusting. You can even treat the main slab at the same time if you like.
Thanks for your advice! This article was very helpful.
We have a concrete floor in the backroom of our workplace. Most of the floor is in much better shape and not dusting except for the corner where i work and paint signs. It’s roughly a 9’x12′ area where we sit at two rolling office chairs and paint at utility tables. Everything in our space gets thoroughly covered in a light dust within a few hours. The floor is lumpy, cracked, dusty and covered in various splatters of paint and spray adhesives. It doesn’t break away too easily but i can make holes in it with a screwdriver. I want to propose to my boss a cost effective way of managing the dust in this corner without taking away too much time from making signs for the store. I am also considering the possibility of getting a rubber garage mat
Hi Alley. A polyvinyl (not rubber) garage floor mat would be the quickest and easiest solution. It would just cover it all up and keep the dust down. The other solution that would be cheaper would be to apply a couple thin coats (not thick!) of a clear water-based acrylic sealer. This is an example from Home Depot. However, it will require that you clean the concrete well and allow it to dry for 24 hours before application. It’s not going to fix lumpy spots, but it will prevent the floor from dusting.
I used a diamond grinder to prepare my floor with epoxy and cleaned it numerous times. Will there still be little traces of dust on concrete and will it be ok to epoxy?
Hi Jason. Yes, some trace of concrete dust is normal. Sometimes wiping the surface down with denatured alcohol on a microfiber mop pad will remove the remaining dust. If you used water for cleaning, make sure the concrete dries a minimum of 24 hours if not longer before applying the coating.
Ok. It has been over 24 hours. I vacuumed the area few times, but I wasn’t sure if the small amount of dust was normal and safe to apply the epoxy. I guess I’m being a little anal about it. Thanks for the reassurance.
I need help with a concrete basketball court. There is a lot of dusting which makes it almost impossible to play due to sliding everywhere. I painted the three point, free throw line and boxes but they peeled up even though I used a concrete adhesive paint. What are your recommendations to paint and seal the court? Thanks!
Hi Chris. If you have dusting that bad, then the only option to reduce it is to grind the surface to remove the very weak layer of concrete on the surface. No amount of coating or sealers is going to fix your issue until that is done. We would recommend a single head or dual head (faster) grinder with 25 grit diamond segmented discs. Your local equipment rental should have one. Make sure to wear a respirator. Once you grind, you can then apply a densifier on the bare concrete and then paint the appropriate lines and markings for the court.
I pulled up a 50 year old tile floor with the intent of putting down a floating wood floor, but the old concrete under the tile is badly dusting. I’m a plumber and craftsman so I’m doing the work my self and will be grinding it down, but I need to pour a self leveler to get it ready for the floating floor. Should I put a hardener down first to prep it for a new surface coat or pour then seal?
Hi JT. The grinding will remove the weak surface layer and negate the need for a densifier. Plus, you don’t want the freshly applied densifier (which tends to act like a sealer) to interfere with the bonding of the self-leveling underlayment.
I recently had a 12’ x 30’ concrete patio poured and am experiencing dusting. I’ve also noticed in areas where leaves have left imprints, almost looking like a fossil. Any recommendations on how to resolve this issue are greatly appreciated.
Hi Frank. We’ve never had to remove leaf stains ourselves, but we’ve had many reports that OxiClean does the trick. Just mix in a couple of scoops to a quart or so of water. Pour it on the stain and let it set for about 10 minutes, but don’t let it dry out. Wet it with solution again and then scrub it with a stiff bristled nylon brush and then rinse clean.
As we state about the dusting, there are a few ways to treat it depending on the degree of dusting you have. If it’s light dusting, then a densifier works fairly well. We would recommend PS104 by Concrete Sealers USA since it’s outdoors. PS104 has a siliconate sealer added which will help to seal the surface at the same time. Because it is penetrating product, it will not change the look of the concrete or change the wet slip resistance. If the problem is more than light dusting, then you will want to apply an acrylic coating. These can be slippery when wet, so an anti-slip media mixed into the second coat would be recommended.
Hi! Thanks for the informative article. I read through the questions, but didn’t see any talking about basement floors. About 4 years ago, we built a new house. Right away I noticed that the basement floor was very dusty. I tried washing the floor with a mop, dusting it, shop vacuuming it, anything I could think of, but no luck. We are still tracking white dust through the house anytime we go downstairs. My husband thought it might be because they put a broom finish on it, but now I’m wondering if we have dusting. Because it’s indoors, I hesitate using a strong chemical on it. I’ve been frustrated with this problem, but try to just ignore it because we don’t use the basement much. Any suggestions will be greatly appreciated! Thanks!
Hello Lynn. Does your basement have any moisture issues? Have you tested the floor for moisture as demonstrated in this test here?
Hi,
Thanks for the answer. I just read it today. No, we haven’t tested it for moisture, but I will do that. Is there anything we might be able to do without putting an epoxy on it? It’s a basement under a ranch house, so it’s big with very little ventilation. I hesitate using anything that has a strong odor. Are there any products that aren’t toxic to use as a sealer? I was thinking about putting some rugs down on the parts of the floor we walk on. Thanks again for your help.
Hi Lynn. Yes, you have some options, but it depends on how much moisture (if any) that you may have coming up through the floor. That is why a proper moisture test is important. If you have little to moisture coming through the concrete, you can apply a water-based clear acrylic coating. It has no VOC’s and is easy to apply.
I did the moisture test and there was no moisture under the plastic. What is the brand of the acrylic coating you would recommend? The one with no VOC’s. Also, I contacted the builder and the person who put in the basement floor said he would wash the floor with white vinegar and water before applying the sealer. What do you think about that idea? Thanks so much!
Hi Lynn. What you want to use is a water-based acrylic coating. This one here is a good example. Apply a minimum of two thin coats. DO NOT apply an acrylic in thick coats. What you don’t want to use is a solvent-based acrylic. Though they are more durable, the solvent that evaporates during application will create VOC’s. The vinegar and water treatment acts as a very mild etch. This will be fine to do, just make sure the floor is rinsed with water and then allow a few days or so for all the moisture in the concrete to evaporate. It takes much longer for the moisture to dissipate and evaporate out of the interior of the concrete when in a basement vs. outdoors or in a garage.
Hi there,
I am in the process of finishing my basement and recently did a self levelling g flood of the floor to meet the specs of the flooring I’m putting down. We did fill a floor prep – ground the floor and coated it with primer. While some spots are good most of the floor is quite soft (I can scratch it with my finger nail) and is dusting. I am planning on putting plastic underpayment down on top of the concrete – followed by Luxury vinyl plank. As well as planning on tiling directly on top of the floor in the bathroom. Do I need to seal the floor first? Or is a more extensive repair required? Or perhaps nothing at all? Any guidance I can et would be appreciated!
Hi Trevor. What product did you use exactly?
I am prepping my floor for epoxy I have used a cement grinder, floor scraper shop vac and various cleaning / etching agents but a light layer of white dust still remains. When I touch the floor my fingertips are covered with a thin coating of dust. I do not want to apply the expoxy over dust just to have it come up later. Are there any products that you recommend ?
Hi Brian. Did you etch the concrete after grinding? If so, why? What type of etch did you use? Also, was the concrete dusting bad before you started your project?