A new trend that has been finding its way onto the surface of garage floors and workshop floors is the use of a concrete densifier with an added sealer. Densifiers have been used on occasion in the garage for a variety of reasons, but rarely as a finished garage flooring treatment. So why has there been a gradual increase in its use and popularity for the garage floor?
The reason has to do with the addition of silicone and siliconate agents in some densifiers to act as a sealer. This helps to create not only a water repellent floor, but one that is resistant to liquids and chemicals in general.
In fact, this combination of a densifier and sealer has fast become one of the best values for a bare concrete sealer.
So let’s take a closer look at how a concrete densifier with sealer on your garage floor may be beneficial for you. In addition, we will discuss what product we highly recommend and why.
How a concrete densifier works on a garage floor
Concrete densifiers have been around for decades. They are a concrete hardener that has primarily been used for concrete floor polishing, increased abrasion resistance, anti-dusting, and moisture mitigation. They are typically applied to machine troweled, hard troweled, and smooth concrete.
In some cases, they are used to treat a soft concrete surface or as a treatment for dusting concrete.
When concrete cures, bleed water makes its way to the surface and increases the water to cement ratio. This process can help to make the surface of concrete smooth. However, it can also create a surface that is softer than the underlying cement. This is due to the increase in laitance content and fine aggregates that the bleed water carries to the surface.
When a densifier is introduced, a chemical reaction is created that can increase the surface strength of concrete from an average of 20% to 40% depending on the original pour and finish of the concrete. But, how is that done?
Densifiers are a water-based chemical solution that first works by penetrating into the surface of the concrete. They react with calcium hydroxide to produce calcium silicate hydrate (CSH). This is the substance that gives concrete its strength.
Next, the CSH that is produced fills the open pores and capillaries of the concrete. This is what increases the density and strength at the surface.
Lithium silicate densifiers are the most common choice used for garage floors and workshops. There are two chief reasons for this.
The first reason is due to the ease of application. Scrubbing in the densifier solution typically is not required like it is for the older sodium silicate densifiers.
The second reason is that lithium silicate has properties that are less reactive to carbon dioxide which can create a whitening effect on the floor. And unlike sodium silicate densifiers, lithium silicate densifiers also do a good job of repelling road salts. Once applied, the concrete retains its natural look.
It’s important to note that concrete densifiers are non-film forming, meaning that they don’t leave a topical film on the surface to protect from staining.
Additionally, densifiers technically are not water-repelling sealers either. They don’t form the same molecular membrane at the sub-surface to repel liquids as other non-densifying penetrating sealers do. This is why they had not been used much as a concrete protectant for garage floors – until recently.
With the addition of silicone and siliconate agents in densifiers, their use as a sealing agent and overall protectant for garage floors has dramatically changed this. These siliconates create a water-resisting agent right at the sub-surface of the concrete.
This addition allows the densifier to act as a sealer for your garage floor by repelling water, resisting oils, and resisting stains. Furthermore, it protects the concrete from chemicals such as road salts, and other fluids.
Lastly, densifiers with siliconate sealers added are environmentally safe. They are extremely low in VOCs and odorless.
Are they 100% impervious to stains and chemicals? No, but if you don’t allow spills to sit for a long period, they will generally wipe right up with little if any scrubbing necessary. However, you must be particularly careful with solvents that can stain, as their resistance to them is minimal.
The benefits of a concrete densifier with sealer added include:
- Added strength and abrasion resistance to the surface of a working garage
- Increases the compressive strength of concrete
- Repels liquids and other fluids which help to make your garage floor stain resistant
- Eliminates dusting and problems with efflorescence
- It doesn’t peel, leave tire prints, or turn yellow
- Helps act as a moisture barrier for your garage floor
- Improves weathering and resistance to freeze/thaw effects
- Non-slip surface
- Relatively inexpensive
- Lasts for years without need for reapplication
- Easy to apply and is ready for traffic within an hour or two
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Concrete densifier sealers we recommend
One particular densifier sealer that we highly recommend is PS104 by Concrete Sealers USA. Why?
This is the same company that manufactures the very highly rated PS101 siliconate sealer which we have discussed before.
The same siliconate sealing agent that is used in the PS101 is added to the PS104 densifier. This is what makes PS104 such a high-performing concrete sealer and densifier. It’s all in one product.
In addition, with an average coverage rate of 200 – 300ft², it makes for a very affordable concrete sealing option. Concrete Sealers USA offers it in both 1-gallon and 5-gallon containers.
Check Price of PS104 – 1 Gallon
Check Price of PS104 – 5 Gallon
Furthermore, we also like the amount of lithium silicate (measured in solids content) that is used in PS104. Manufacturers generally have to perform a balancing act between how much lithium silicate can be included for densifying purposes and how much siliconate can be added for sealing the surface.
If too much lithium silicate is used, it makes it difficult to add the desired amount of siliconate for the best sealing performance. It also makes the product more expensive.
As a result, many of the densifiers with siliconate sealer added have a lower solids content of the lithium silicate in order to keep the price point down and manufacturing of the product easier. The results, however, are less effective densifying properties.
Concrete Sealers USA has found a way to use almost the same amount of lithium silicate in their PS104 as they do in their standard PS103 densifier. As a result, you can expect close to similar densifying performance as a straight densifier plus the added benefit of the siliconate sealer.
How to apply a densifier to a garage floor
The application of a densifier sealer for your garage floor couldn’t be much easier. You first need to make sure your garage floor is clean and free of all dust, oils, and foreign contaminants. Any stains that you have will essentially be locked in unless removed first. The surface must be completely dry before applying the product.
The easiest way to apply the densifier is to use a garden sprayer with a circular spray tip or a microfiber mop out of a paint tray. Work in sections making sure to keep a wet edge at all times.
You want to get the concrete wet with the product, but not so much that it puddles. If it does puddle, work it into the concrete with a short bristled deck brush or wipe up the excess. If you allow the puddles to dry, you will get a white residue that requires intense scrubbing to remove.
Once applied, you can return the floor to traffic within a couple of hours or so. One application is generally all that is required.
One note to make is that if you plan on adding a topical coating at some point in the future, you will need to grind the concrete in order to remove the sealer and provide a mechanical bond for the coating. Acid etching will not work because the etching solution will not be allowed to penetrate the surface sufficiently in order to react with the concrete.
If you like the look of bare concrete and have a working garage or shop floor that you want to protect without making a big project out of it, then a concrete densifier with sealer added can be a good solution for you. It’s easy to apply, relatively inexpensive, and will provide years of protection for your concrete. In short, it’s one of the best values in concrete sealers today.
E1 says
I have purchased Armor L3000 to harden my floor before applying an Epoxy top coat. I had planned to grind my floor and then use L3000, but I have been told that I should apply L3000 before mechanically grinding the floor as the L3000 would seal the pores in the concrete and make it hard for the epoxy to grab hold. This seems counter intuitive as this would either grind off the L3000 (assuming it only seeps 1/4 inch or less below the surface), or it would still leave pores filled at the sub surface even after grinding (assuming it seeps below a 1/4 inch of the surface, which is what I would expect it to do).
Assuming I would only be applying 1 coat and not allowing puddles to form, am I really better off one way or the other?
Shea says
Hello E1. Applying a densifier first then grinding is standard procedure for floors treated before a coating is applied. Though a densifier penetrates the concrete, it would effectively reduce or help to smooth the mechanical profile of concrete that has already been ground, thus reducing the most effective adhesion of your epoxy and increasing the chances of delamination. It does this by filling the open pores (which you just exposed) and some of the mechanical profile (from grinding) with calcium silicate hydrate.
The effects of a densifier will typically penetrate deeper than 1/4″. It’s a reactive sealer that takes about a week to go through it’s full process. Also, grinding will only be removing about 1/64″ of the concrete surface. Grinding after application puts a fresh profile to the surface that will allow the epoxy to mechanically adhere to.
E1 says
Thanks for the insight, the Armor guys said a similar thing and because the densifier smoothes out the profile it makes sense to grind after words. Just as a note, the Armor guys said L3000, depending on porosity of the concrete, will penetrate any where from 3/8″ to 6″.
Thanks!
Shea says
You are welcome E1.
Tom Philip says
I have a new garage slab and am planning to do a porcelain tile floor eventually but need to put it off for a year or two. Would a densifier / sealer product like L3000 or PS104 be a good choice in the interim to help resist staining and decrease white dust? Would those products require grinding before a tile floor could be laid on top? Thanks!
Shea says
Hello Tom. Any sealer that is applied to the concrete prior to installation of tile will need to be ground off the surface or the mortar will not adhere well. L3000 densifier by Foundation Armor is stand alone densifier while PS104 by Concrete Sealers USA is a densifier with siliconate sealer added. A stand alone densifier technically does not seal the concrete. It hardens the concrete which can have a “sealing effect” since the reaction of the densifier fills many of the open capillaries with calcium silicate hydrate. It does not form a membrane at the subsurface like a sealer does. If you used a stand alone densifier you may or may not need to grind. It depends on how dense your current surface is already and how much moisture the surface will absorb when it comes time to tile a year or two down the road. Unfortunately, there is no definitive answer to your question if you use a straight densifier.
Inger says
I read lots of these comments…haven’t made it through all (yet). I had a slab poured in May 2017 with an admixture for water repellancy (Rheomix 235 on ticket). We built a shop on it this past summer and fall. Now preparing to clean seal the floors and then seal the sawcuts with backer/self leveling sealer. Will the admixture prevent a densifier/sealer such as PS104 from working as intended? This will be used as an hobby auto shop. Thanks in advance.
Shea says
Hello Inger. As long as the slab will still absorb water and not bead, you will be able to use such a sealer without additional concrete surface prep other than cleaning.
up-on-two says
just finished pouring and troweling a 24 x 60 shop floor today. I will install a Web Steel building in about a month. So, my questions are these:
1. What’s a good densifier to choose?
2. How long should I wait before applying the densifier?
3. It’s November now, and cool. What difference does that make??
Shea says
Hello up-on-two. We recommend the use of a lithium silicate densifier. They are more effective and easier to apply than the older formulated sodium silicate densifiers. You need to wait at least 30 days for the concrete to cure (assuming a 4″ pour) before application. Temps during application typically need to be 40 degrees or higher. In terms of product, we know that Concrete Sealers USA turns out some very good densifiers. They use some of the highest concentration of solids. If you want a densifier with the added siliconate sealer to seal the surface, then no one that we know of has a better product than their PS104. If you want to use just a straight densifier without sealer added, the that would be their PS103. Foundation Armor also has a good straight densifier which we tested and wrote about here.
Up-on-two says
Thanks for your help. I had a 6” pour with rebar and microfiber. Will that require a longer cure time before adding the densifier?
Shea says
Yes. Typically you will add a couple more weeks for the majority of the moisture to work its way out.
up-on-two says
Excellent! Many thanks. I’ll give it plenty of time to cure and dry.
tspain says
Hi, i have a high traffic residential garage floor – 2 cars, bikes, etc. as well as the main entry to the house. Always had a problem with concrete dust and several years ago applied a rust-o-leum 2 part epoxy floor coating. Followed the directions to a T, looked great but was completely up within 2 years. I am thinking that I should be sealed, but not sure if a densifier or a MMA sealer is better to solve the dust problem. I would like to add a dye to the sealer, and if a densifier is the best option, can a dye be used. Looks like it can be used with a MMA sealer.
Shea says
Hello tspain. A dye cannot be used with a densifier. It is a penetrating sealer that is designed to penetrate the surface of the concrete. Additionally, dyes need to be coated with a clear sealer in order to make the color wet out and pop. If a dye is not coated, it will look dull and unattractive. We do have an important question before we can answer the rest of your questions. When the Rust-Oleum epoxy came up, did it have white residue on the back of the coating or was it fairly clean?
tspain says
Good question, it has been more than a couple of years and it flaked of so the pieces were small. The dust however was prevalent in the area ls where it came up first so I assume ls it was efflorescence. Not sure if this answers the question. Might the issue be something else?
Shea says
OK, this raises another issue. Efflorescence is caused by moisture, not dusting. If you have moisture issues then that would be why the coating came up. Have you done a moisture test during the wet periods of the year? Also, has the coating been completely removed and if so, how?
tspain says
I equated efflorescence with the white dust that i have been experiencing and could be mistaken. I did try a moisture test – taped a small sheet of clear plastic to the floor and did not find any moisture on the plastic the following day; however the dust prevented the tape from sticking for any lengthy period of time i am sure. The coating is completely gone from most of the garage floor. There are areas where the coating is still visible on the perimeter of the floor, beneath some wall shelving and on portions of the 2 foot or so high wall that surrounds the floor. There is a significant amount of moisture in the garage particularly in the winter months when there is snow melt from the vehicles, garden tools and a gas grill that has been replaced have become rusty.
Shea says
If your coating came up just about everywhere on its own, then you most likely have a serious dusting issue that is going to require some thought on your part on how much you want to address it. Can you create a shallow groove in the concrete with a sharp screwdriver? If so, then your dusting problem is serious. This article about dusting explains why it happens. Applying another coating (MMA acrylic sealer for example) is not going to solve the problem as it will eventually come up like the epoxy did. The easiest option would be to clean the concrete well and then apply a densifier with sealer added just like the one we discuss in this article. It will not completely stop a serious dusting issue, but it will dramatically reduce it. The second option would be to grind the concrete and apply a commercial quality coating. A good grind is going to remove the weak layer of concrete that causes the dusting and allow a good coating to adhere like it should. If this is more than you feel comfortable tackling yourself, our advice would be to contact a commercial garage floor coating company. Most will come to your residence, inspect the concrete surface, and give you a free quote. Plus, it will give you a better idea of the shape of your concrete surface.
Leroy W Atkins says
Can you paint a two part epoxy over a concrete densifier on a garage floor?
Shea says
Hello Leroy. For most applications you cannot do this without first grinding the concrete. The densifier prohibits a good acid etch and also prevents a coating from penetrating very well. The one exception is for some of the low solids DIY store bought kits such as EpoxyShield and etc. Sometimes they state you can apply a densifier to the concrete after it has been etched first if there is concern about moisture. You can then apply their coating thereafter. However, it is not recommended at all for higher solids, higher performing coatings. You must grind first.
RM says
Hi, I have an unusual situation here and I’m hoping you can help. I have a small room in my slab-on-grade home that will be dedicated to cat boxes. Cats will sometimes “miss” and I’m looking for something that will seal up the concrete and prevent any mishaps from soaking in.
Here’s the challenging part: this section of the slab has a severe moisture problem. I suspect the vapor barrier underneath was compromised before the pour and the subcontractor simply didn’t care (they dropped the ball in a number of other areas as well). When I pulled up the existing carpet there were salt deposits caked onto the slab. I want to seal this up and stop this moisture (and potentially radon) from entering my house. Because this is indoors I cannot realistically etch with TSP or muratic acid as there’s no way to hose it off afterward.
I’m looking for a solution that will tolerate this very challenging situation… Perpetually damp and dirty slab, salt deposits (which I’ve cleaned up as best I can), and biological assault from above. Fortunately I don’t need anything highly durable (there’s only minor foot traffic) and I don’t need anything cosmetic as I’ll just have carpet installed when I move.
I’ve used latex-based DRYLOK in a different room with far less moisture and no deposits and it seems to have worked quite well. Carpet was installed over it. I’m wondering if I can repeat that success in the cat room by starting with either this densifier or possibly a retail concrete primer. Zinsser Lock Down claims their primer is good for up to 13 pH, appears to tolerate efflorescence, and seems to deal with moisture given that it can be used prior to 30-day cure. Even the general purpose Zinsser 1-2-3 claims to tolerate pH 12.5 and I have some of that hanging around already.
Any thoughts on this dilemma?
Shea says
Hello RM. Yes, you don’t have an easy solution for your issue that would not require bringing in professionals. Both DryLok and Zinsser require that you clean off the salt deposits and efflorescence first or it will not adhere – period. Of the two, DryLok is the better solution because it will withstand up to 10 lbs or hydrostatic pressure where as Zinsser will not. The best way to prep is to use TSP or an Eco friendly concrete etch such as this one by Rust-Oleum. The way to do it is to lightly wet the concrete first using a water can. Apply the TSP or etch formula and scrub with a deck brush to loosen up the the salt deposits and efflorescence. Once done, add some more water and then begin sucking up the solution with a wet vac. Keep rinsing and sucking up the solution until you are confident none of the residue remains.
After it has dried, an application with a densifier is a good idea. It will help to block the flow of moisture from underneath. However, you do not want to use a densifier with silicontate sealer added. The siliconate sealer is designed to prevent moisture intrusion on top of the surface, not the other way around. It will effectively prevent the DryLok from adhering very well. Use a straight densifier such as PS103 from Concrete Sealers USA or this one here. Allow the densifier to dry for 24 hours then apply the DryLok. As you most likely know, DryLok and Zinnser are designed for vertical surfaces and floors, so don’t expect it to hold up with much traffic.
Joanie says
Hi, Shea– I just posted a question to RM above, to hear whether they ended up using all or part of your suggestions. If, after a couple more years of experience and the introduction of new products, you have any other thoughts for our situation, please toss them our way! Thank you, Joanie
Shea says
Hi Joanie. Our notification system does not work like a forum. The only way RM would see your questions is if she checks back. We did post it though. Have you read our article about eliminating pet odors? It can be very successful if properly implemented.
Joanie says
Ah. Thank you for your reply. I’m reading the pet-odor page now, along with the comments–it’s all very helpful. Does your recommended process work as well for odors NOT caused by animal urine? The odor we have had does not seem like urine, although I’m not positive about that.
Shea says
Hi Joanie. Recommended process is for pet urine odors and does not necessarily pertain to other biologicals that could be causing an odor. A black light will expose if there is urine that you are dealing with.
Joanie says
We did have a professional with a blacklight, and he did find several areas that showed up–but he said it COULD be urine, or it could also be caused by some cleaners/carpet products that the previous owners may have used. I’m not sure how this compares to your experience though. Thoughts?
Shea says
A black light will reveal many liquid remnants as well as other biological fluids and mold. Your nose is a good indicator of what you may have as well. TSP with a little bit of bleach will not only remove bacteria from the concrete due to urine, it will also kill any mold that is present. Cleaning the concrete as we describe and then treating it with enzymatic cleaner would be the first on list of things to do if we weren’t positive about what we were dealing with.
Joanie says
RM, if you get notification of this question 1.5 years after your initial posting, I’d appreciate hearing what you chose to do, how it went, and how successful you feel it’s been. My husband and I recently moved into a home that, while the seller denied any water issues in the walk-out lower-level, had a terrible odor trapped in the carpet padding downstairs. The odor was not everywhere but was in enough different locations to cause us to want some kind of sealer throughout. (We’ve torn out carpet & padding, and have cleaned and sprayed with an antimicrobial.) We want to do something preventative that sounds similar to what you were looking for. We’ve had several professionals in but they are split on seal vs. don’t seal. Confusing! But Shea’s reply to you sounds the closest to what we’ve been thinking about ourselves. I hope your slab is doing great! –Joanie
KENT BECKER says
I have a two story garage and the upper level is where my cars are kept. The concrete is letting water and winter salt leak into my lower level. I need ideas on how I can stop this. There are cracks in the floor, nothing big.
Shea says
Hi Kent. Suspended garage floor slabs produce their own set of sealing issues and are not always easy to rectify. After thoroughly cleaning the concrete to remove any salts, the first place you need to start is to properly seal all expansion and contraction joints with a self-leveling polyurethane sealant. SikaFlex is one such product. After that, you will want to properly repair any cracks. Though they may not be big, water and salts migrate through cracks and cause damage. After all the joints and cracks are sealed, you can then apply a densifier with siliconate sealer added. It will help to protect the concrete from salt damage and reduce any water migration through the concrete. This is the low budget solution. If you still are experiencing leaking, then we recommend calling in a floor coating company that is experienced with sealing suspended garage floors.
john says
I live in the Northern part of Canada and the salt/snow melter chemical the city have been using the past few years have been stronger that they’ve used in the past.
I was planning to apply lithium silicate densifier sealer on my driveway.
What if the seal coating gets eaten away – can I re-apply the same product OR can I just put a new acrylic seal coating on top of it? From what I understand, densifiers basically close-out the pores on the concrete surfaces. So if I want to put on acrylic seal coating the sealant may not be as effective since it wont have something to “latch” into.
Thanks!
Shea says
Hello John. A properly applied densifier should do a good job at protecting the concrete. We would recommend one with siliconate sealer added if you can find it in your area. It will do an even better job at keeping the liquids at the surface. Though you could apply an acrylic coating to the driveway sometimes afterwards, we do not recommend it due to your climate. Because it is a film forming coating that creates a much smoother surface, it will require an aggressive anti-slip additive to prevent slipping and sliding in the winter time. In addition, the coating will be damaged from snow shoveling, studded snow tires, and etc. that come in contact with the surface.
john says
Thanks Shea. Just a quick follow-up. Whats the difference between a silicone based sealer from a siliconate based sealer?
Shea says
Silicone sealers are non reactive and have a larger molecular structure that tends to sit more on top of the surface. As a result, they wear quickly and require yearly reapplication. They are better suited for concrete or masonry walls. Siliconate is reactive and causes some changes within the concrete at the surface to form a barrier. The molecular makeup is smaller (not as small as silane or siloxane though) than siliconate and as a result it sits just at the surface and not on top. This means that the sealer can only wear as the concrete wears. Reapplication is recommended approximately every ten years or sometimes a bit sooner if it’s a harsh climate. This article here explains more about how siliconate sealers work.
Mike says
Great article! I am wondering if i can use the PS104 on my driveway because it is starting to pit near the entrance of the garage where the salt and deicers drain out of my garage after it melts off the bottom of my car. The driveway was sealed 4 yrs ago with an acrylic sealer. I was reading that you cannot use a densifier on concrete that has been previously sealed. Is this true and why? Or can I still use the PS104? If not, what would you recommend?
Shea says
Hi Mike. Densifiers work with bare concrete and not coated or sealed concrete. The reason is that they need to penetrate the surface in order to react with the minerals within the concrete. If the concrete is coated with a acrylic sealer, then it is effectively blocked from getting good penetration and cannot react with the concrete. Our guess is the acrylic coating has worn away in areas where the pitting is occurring. Do you know what brand acrylic sealer it was? Our suggestion would be to reapply the acrylic sealer or remove it entirely before applying PS104.
Mike says
Thanks for the response! Sorry, I am not sure what brand the builder used to seal the driveway. Can I use a silane/siloxane sealer over the old acrylic sealer or does it have to be an acrylic sealer? Also, I used a silane/siloxane sealer from foundation armour on my garage floor and the smooth concrete top surface has peeled away where the tires sit exposing rough sandy concrete under it. Can I use the PS104 on this area to help strengthen the part where it is peeling and the area where it has already flaked off or can I only use the same silane/siloxane sealer here as well? BTW I live in Chicago where deicers are used a lot in the winter months.
Shea says
Unfortunately no, Mike. It’s the same issue. You cannot apply a penetrating sealer of any type (which needs to penetrate into the concrete) on top of a film forming topical sealer (which acrylic is). It effectively blocks the penetrating sealer from getting into the concrete. Acrylic sealers are a topical coating that are either solvent-based or water-based. The solvent-based are more durable and generally used for outdoors, but not always. You can reapply a solvent-based acrylic on top of another solvent-based acrylic, but you cannot apply it over a water-based acrylic. It will soften the sealer and cause a mess. And water-based acrylic does not adhere to solvent-based acrylic. That is why it’s important to know what was used beforehand. You can always test by placing a teaspoon of Xylene on an area where the coating is clearly visible. Let it sit for 15 sec. and then wipe it off with a rag. If the sealer is tacky to the touch, then it is solvent-base. If not, then it’s water-based. Yes, you can apply the PS104 over the silane/siloxane sealer. For more information about PS104 and application, I would recommend contacting Concrete Sealers USA directly. They have great customer service and provide very candid information about application and use.
Nicholas russo says
Hello, this is a great article. Thank you, we are pouring a 6” slab with microfiber and rebar next week…it’s going to be in the 40s unfortunately and less at night. We have plenty of blankets though.
The concrete guys were planning to use J20 after burning the surface with a power trowel
This is a light machinery repair shop, plasma cutting whole and auto repair shop….would I be better off having them apply a densifier?
I think part of his goal in using the J20 is to help it cure properly due to the weather?
Shea says
Hi Nicholas. Your concrete guy may indeed be using the J20 cure and seal due to the weather, though the blankets can work quite well in that regard. It can be applied in temps down to 35F. The J20 is an acrylic coating that will leave a glossy finish to the concrete. It’s not going to be a very robust coating though for the type of work you plan to use the shop for. It will burn fairly easily and get scratched if anything is dragged across it. It works fine for warehouses that see foot and forklift traffic, but not general automotive repair and etc. Solvents, brake fluid, and gasoline left to sit for a few minutes will cause it to deteriorate and soften.
Densifiers are rarely used as a cure and seal. It’s generally accepted that they should not be applied any sooner than 14 days after a pour, which is far too late to be effective as a cure and seal. They are generally applied after the concrete has cured for 30 days or so. This type of system here has become very popular for heavy use floors such as yours. You may want to have a discussion with your concrete guy if the J20 is essential or not for the curing process if you don’t want to deal with a coating.
Nicholas russo says
Hello Shea, thank you for the reply. I somehow missed it…months later we are still looking to densify or somehow protect the concrete from oil, gas and abrasion. They did use the J20 for curing reasons, we had a cold snap while pouring…the finish is great but there is some minor crazing.
What do you recommend I use at this point? Do I need to remove the J20 somehow ? Grinding is not an option…..is there a great densify and seal that I can use? Prep and product are my main questions?
Thank you for your time and knowledge
Shea says
Hi Nicholas. Right now nothing can be done until the J20 is completely removed. It is currently acting as a barrier that will prevent sealers and coatings from being applied. The Tech Data sheet for J20 states that it can be removed with J-48 Citrus Peel. Once that is done, you can then treat the concrete.
We would recommend that you use a combination densifier and oil repelling penetrating sealer for your use. This product by GhostShield is still getting great reviews and is fairly easy to apply. It’s not a coating so you don’t have to worry about damaging it like you would with a coating. It does a great job of resisting stains from petroleum products as long as it is not allowed to sit for a period of time.
Stewart Colley says
Would a densifier be better, or as good, as a straight siliconate sealer to prevent urine from penetrating into the concrete of a kennel floor? If not, what would be the very best product to use for this?
Shea says
Hi Stewart. A straight densifier by itself will provide the least amount of protection. A densifier’s main job is to harden the surface of concrete. A densifier with siliconate sealer added would do much better. A straight siliconate sealer will provide the most protection of the three. However, these are all classified as penetrating sealers. They do not leave a film-forming topical coating on the surface. As a result, if urine is left to sit for long enough over and over it will eventually make its way into the concrete. How often the kennel floor is cleaned would play a big role. The only product that will prevent urine from entering concrete, not matter how long it sits, would be a film forming coating.
Stewart Colley says
Thank you very much for the quick response to my question. Could paint be used over the siliconate sealer?
Shea says
Yes, paint can be used over a siliconate sealer. However, paint is not a true coating and is not considered a sealer.
Scott says
If I were to apply stain or dye, would a densifier (either combination sealer or not) go on after the sealer?
It seems right to me that the color goes first, but reality rarely agrees with me so readily,
Shea says
Hello Scott. After you apply a stain, the next step is to apply a film forming topical sealer. This is what makes the colors pop with vibrancy and give stains the appearance they are known for. They alos protect the concrete and stains. Densifiers and penetrating sealers will not do this since they penetrate into the concrete and do not form a film (coating). They do not change the look of the concrete, they do not form a topical coating, and they will not makes stains and dyes pop with color. This article here explains how this process works.
Scott says
I’m considering adding dye, densifier, then a sealer.
The only reason for the densifier is… well, it seems like a good idea to strengthen it.
I am interested in darkening the grey floor to something more interesting. A super-shiny fancy surface isn’t necessary, as it’s a garage that will see winter use. But it should look decent.
Another possibility is skip the dye and just do the densifier/sealer combination. Still deciding what to do.
Shea says
I see. We recommend that if you are interested in the dye, you should purchase a sample kit to test in an inconspicuous area of your garage floor. That way you can see what it looks like after it has been applied and dried. Some people don’t care for the look of dyes and stains without the proper coating, but you might. It’s a great way to find out before you get started on anything.
Scott says
Oh I definitely want to seal it, it just doesn’t have to be high gloss.
Shea says
You might want to read this article about sealers to determine what type you think you want, Scott. After that, you may want to look at this topical sealer here. It’s a matte finish and does a good job of protecting the concrete and even better at preventing stains.
Scott says
I have read.
My question is, can I use all three?
If yes, is the order stain/dye, densifier, then sealer?
Or is it densifier, stain/dye, then sealer?
Shea says
You can use any over stained concrete. With the exception of polished concrete, the stain is always applied first. A penetrating sealer can be applied after a densifier, however, most coatings cannot be applied after a densifier unless the concrete is grinded after the densifer is applied. The reason is that the densifer effectively blocks most coatings from penetrating and making a good mechanical bond.
Scott says
Ok. So it looks like I can stain/dye first. Then follow with either the TS210, or PS104. Will the latter work since it’s one product? Or will it be too dull?
Shea says
You are correct about the application, Scott. The PS104 will not change the look of the concrete since it’s a penetrating sealer. So how it looks right now or how it looks after it has been stained/dyed is exactly how it will look after it had been applied and then dries. It has no effect on appearance. The TS210 is a film forming coating. As a result, it will ever so slightly darken the overall look and provide a matte sheen.
Catherine says
Our garage floor is 24×24. We purchased the home six years ago. We have had an issue with the concrete being very slippery when wet. This problem occurs in the snowy winter months and the humid summer months. We do not know if there is a vapor barrier beneath the slab.
To attempt to combat this, we invested WAY too much into a SpreadRock system. We used an interior/exterior textured bonding primer (Penetrating, Anti-Slip). We then used the Stone coating concrete resurfacer and sealer. We finished it off with a satin clear coat sealer with urethane.
We insulated the garage walls and ceiling and got a non-vented natural gas heater. This led to condensation, so we also purchased a dehumidifier. We were looking forward to a great winter with our newly prepped garage!
We loved the look of the floor — which lasted about a week before it started to bubble and lift from the surface. After one winter in Michigan, the floor was a total fail. Most of it has lifted and is no longer there. (Some parts of the floor still have the coating in place).
We need to do something to fix the floor. That being said, not really sure where to start. (Removing the floor and starting over is not an option). I think we would want the PS104 densifier? I’m unable to determine, however, what sort of surface prep we need to do prior to application. Because of the products used last summer, I’m not sure if removing the rest of the stone coating is enough? Do we need to etch? Grind?
Finally, I see that PS104 will lead to a slippery finish — which was the main issue we were trying to address!! — what would you suggest in order to make this a more traction-friendly finished surface?
I have read through all of the answers on these threads, and have been impressed by the thorough responses. I’m hoping you can help us fix our issue as well!
Shea says
Hi Catherine. Wow, there is a lot going on here 🙂 We looked up the data sheets on SpreadRock. Some of these rock/granite systems can be fairly durable. They require an aggressive acid etch or grinding of the concrete and use a 100% solids epoxy to mix the stones in and spread thickly on the concrete. They are then top coated with a polyurethane or polyurea. These type of systems are usually applied by professional installers due to the prep requirements and the shorter working time of epoxy. SpreadRock, on the other hand, is a rock/granite system that uses acrylic. Acrylic is easier to work with and makes for a better DIY product. However, it is also much thinner than epoxy, it is less durable, and it does not adhere nearly as well. While it may work fine for patios and walkways that only see foot traffic, we would not recommend it for a Michigan garage floor. The reason it has peeled up right away may have less to do with moisture than it did with the concrete prep prior to application. Was a sealer every applied previously at some point on your garage floor? If so, etching would not have removed it and the acrylic would not adhere like it should.
The moisture issues that you describe sound like a classic case of what is referred to as “concrete sweating”. This is when relatively warmer and moist air comes in contact with a cooler concrete slab that is below the dew point. When is has a chance to settle, it condenses on the surface and makes it wet. This article here explains more. Have you ever done a proper moisture test?
The PS104 that you are asking about is a concrete densifier with siliconate sealer added. It can only be applied to bare, untreated concrete. It cannot be applied to other surfaces. Additionally, it is not slippery. It retains the same slip resistance as bare, wet concrete.
Unfortunately, before you can do anything with your garage floor, it is going to require removing the SpreadRock system first, which includes any residual primer and acrylic coating. This is going to require grinding of the garage floor. You can’t just apply something over it. All concrete coatings and sealers need the proper surface to apply them to in order to work properly. I know this is not the answer you wanted to hear, but it’s the only way solve the SpreadRock issue and prep the concrete for something much better.
Roger White says
Hi there,
If my concrete is already treated with lithium silicate densifier, can I still apply sodium silicate?
Thanks
Shea says
Hi Roger. You can apply sodium silicate over a lithium silicate, but unless you are polishing the concrete, it will have little effect.
Dew says
Does it matter if I use a densifier with a sealer or not, if I then want to coat it later? I’m thinking that if I have to grind the floor either way to coat it later, then I might as well use the densifier+ sealer now. Is that right? It’s a new floor. I live in a very cold zone and want to protect it for first winter; then maybe do a polyaura next summer. I thought I might just use the straight densifier until then, but if I’ll have to grind anyway, then I figured I might as well use one with the sealer now? Is that right? Can I use one with the sealer, then grind it to add a polyaeura coat later on?
Thanks.
Shea says
Hi Dew. Yes, if you are going to grind the floor later for a coating, then a densifier with siliconate sealer added would be fine to apply. The grinding will remove the sealer and prep the concrete for the coating.
Dew says
Thank you. I had a follow up question, please. Would there be any benefit to applying the sealer and densifier independently, rather as the mixture? I want to get the strongest possible effect from the densifier. The old floor was utterly destroyed from the moisture and freeze when I moved in, and I really want the best possible result with the densifier on the new slab, even if it’s an extra cost. Thanks.
Shea says
Yes, there would be, Dew. I think you would be interested in a densifier and sealer system by GhostShield. You can read about it here. You apply their 4500 densifier first, wait 7 days for it to react with the concrete, and then you apply their 8510 oil repellent sealer. This combination makes for an excellent penetrating sealer and hardener for a shop floor. It’s become quite popular the last couple of years as more people become aware of it.
Dew says
Ok, great. Thank you!
William Hueske says
I have a concrete garage floor that is two years old. The floor has white stains and very small “spider web” like cracks that were there after curing, which I would like to buff, sand, grind (I don’t know which would be best to eliminate them) out! I just want a nice gray concrete colored surface that I can seal or protect. It is just a shop nothing fancy!
Anyway, what is want to do is lightly get rid of the imperfections with a 1500 grit pad and then put down a densifier to harden and then seal it. Will using the 1500 grit pad “open” up the surface enough to accept the identifier?
Shea says
Hi William. No, a 1500 grit diamond impregnated pad is not going to do much if anything at all. That type of pad is used for the actual polishing process and that is only after multiple passes of grinding discs and then resin bonded diamond honing discs. The process starts out very aggressive and then works its way up. I suggest you read this article here about polishing concrete. It will give you a much better idea of what it takes to get to a 1500 grit pad.
For what you want to do, you will need to start with a minimum of a 25 grit disc if you want to remove any concrete from the surface. More than likely it will take a 16 grit disc if you are trying to remove spider cracks. It takes quite a bit of grinding to remove a very small layer of concrete. If you can live with the spider cracks, then you could start with a 40 grit disc, them move to an 80, and then a 140. After the 140 you could add the densifier and then decide if you want to hone from there.
Scott Lundquist says
Sorry if this has been covered before. I am going to use PS104 on my 10-year old garage floor. There are several “run of the mill” cracks which don’t bother me that much, but if I wanted to fill them, would I do that before or after the PS104? thanks…great info on this site!
Shea says
Hi Scott. It’s best that you take care of the cracks first. PS104 has siliconate sealer added which may affect the adhesion of the product/s you intend to use.
Ken says
Hi, I have a 35 yr old 2-car garage in Minnesota (Twin Cities) that gets lots of exposure to road salt in the winter. The concrete slab is in decent shape but is definitely pitted (I don’t think it has spalling b/c I can’t see any rebar but some of the pitting is large). I believe the slab has never been treated – at least it hasn’t in my 10 years of ownership. I just want a simple way to protect it from further salt/water damage so the slab lasts for years to come. I like the concrete densifier/sealer you highlight in this article but first want to confirm it’s right for my project. If it is, I am also wondering what sort of repair/cleaning/prep I should do prior to putting on the densifier. Do you have any links/articles that lay out what I should do in advance of putting on the densifier/sealer?
Shea says
Hi Ken. PS104 is an excellent product for that. First you will want to clean the concrete. We have an article here for that. We also have an article here about removing salt residue if that is needed. Lastly, we have an article here about repairing spalling and pitting. We would recommend a polymer-modified concrete patch for that. Keep in mind that repairs are never going to match the existing concrete. Also, polymer-modified repairs do not react as well as standard concrete when using penetrating sealers. This is because it lacks many of the minerals in standard concrete. However, the repair material is much more resistant that standard concrete to freeze thaw and other issues related to road salt damage. In addition, you never want to use regular concrete for repairs. It does not adhere well and is weak when applied somewhat thin. If you have any questions about PS104, just give Concrete Sealers USA a call. They have excellent customer service.
Eric says
I’m building a metal building in Texas part for a shop and part for a living area. I have no plans to install any other flooring other than the concrete but would like to seal it and it looks like densifying it is a good option too. I’m torn between the PS104 and the L3000. I realize that the PS104 is a dual sealer and densifier and the L3000 is just a densifier. Would you guys recommend the PS104 and be done all in one shot or the L3000 by itself or in conjunction with another product to seal?
Thanks for the great article and all the replies to everyone’s question.
Shea says
Hi Eric. We would recommend the PS104 by Concrete Sealers USA over the L3000 by Foundation Armor. The reason is that the added siliconate sealer in PS104 does a much better job at resisting stains and protecting from moisture intrusion than a straight densifier will. It’s one of the best options available to seal and protect concrete for a single application penetrating sealer.
Eric says
Thank you for the reply. I have since found SX5000. Would you still go with the PS104? I’m not so worried about stain resistance as I am with stain repellent where I have a chance to clean up something before it stains immediately. Maybe I don’t even need a densifier but it just seems that it’s an added bonus. Just want to keep the floors looking nice as long as I can. It’s also important that it not be slippery either. Thanks again for the reply.
Shea says
Stain resistance and stain repellency are basically two ways of expressing the same thing, Eric. If a product is going to allow you a chance to clean something up in a reasonable amount of time, then it’s going to be stain resistant/repellent. Where you want actual repellency (beading) is with petroleum products. We are not the biggest fan of silane siloxane mixes as a penetrating sealer for garage floors. Though they are great for beading water, they are oleophilic and tend to attract oil. When oil is allowed to leave a stain with silane siloxane mixes, it will actually create a permanent stain in concrete that cannot be removed. PS104 does much better than typical silane siloxane mixes for resisting oil stains. If you want the ultimate stain repellant 1-step sealer and don’t mind spending more money than the traditional sealers, then you might want to check out this one here.
Jon says
I have a new garage slab that has cured for several months and am planning to use your CONCRETE DENSIFIER SEALER PS104 by Concrete Sealers USA. Thus far, the garage has not been used and is free from stains. Do I need to etch the concrete prior to application, or do I just need to clean well prior to application?
Thank you-
Shea says
Hi Jon. All that is required is to make sure the concrete is clean and dry.
William Hueske says
Hi Eric,
I’ve posted before and enjoy the information you give out.
I want to know that if I use PS104, can you use another sealer over it for further protection?
Shea says
Hello William. PS104 can only be used on bare, untreated concrete. It cannot be used as a sealer on other finishes or sealers.
kurt smith says
Hi All, a typical light grind orc salt and pepper floor. I’ve applied Ameripolish 3D HS densifier on after 100 grit resin , but i think i put it on too thick if that’s at all possible. I sprayed it on over the whole area and then proceeded with a microfibre to keep it wet with no puddles. 1 hour later it was dry and I continued to polish to 800 grit. When i was ready to seal with SR2 i noticed there were lines of densifier visible on the floor. I tried to remove a small area with 100 grit but that didn’t work. Any ideas what this could be. I can’t afford to leave the floors like this. i’ve always used pentrasil lithium with no issues but other contractors say Ameripolish is the way to go
Shea says
Hi Kurt. We looked up the product data sheet for this densifier as well as the safety data sheets to see if we could determine some of the ingredients (trade secret – rolly eyes). Neither provided much information. Since they tout this product as a Hybrid, our guess is they used a percentage of sodium silicate which is known for causing issues like this if too much is applied. It may require a regrind to remove the offending lines. Before you test a regrind though, we recommend that you contact the manufacturer and discuss the issue you are having. They should be your most important source of info right now. Good luck!