The number one arch enemy of concrete is water. Not only can water create harmful health risks with the growth of mold and mildew and create numerous problems for homeowner’s foundations but it can also be a carrier for salts and chlorides that can damage reinforcing steel in concrete leading to spalling and cracking. In order to prevent water from damaging concrete basements, driveways and other surfaces a waterproofing concrete sealer should be used. A lot of sealers on the market are elastomeric, latex based or acrylic based and while they can temporarily help to reduce water is only a matter of time before they delaminate. Since they are unable to penetrate but instead coat the surface it is more like putting a bandaid on the problem instead of sealing from within.
By using a penetrating, impregnating sealer that densifies and hardens concrete and also provides a hydrophobic surface barrier you can ensure a fully waterproofed substrate. One of our favorite concrete waterproofers is Lithi-Tek LS 9500. This sealer is an invisible, penetrating concrete sealer that will not only densify concrete, but it will waterproof and help to prevent deleterious organic growth. The chemically reactive and active ingredients seal the pores within the substrate adequately blocking surface moisture while still maintaining the concretes ability to breathe. It will not significantly modify substrate appearance or traction and will only wear away if the concrete surface itself wears away. New or existing concrete can be treated and performance can be improved in as little as two applications. The concentrated nature of the sealer allows for 1000 sq. ft. of coverage per coat from 1 gallon (two coats are recommended so each gallon will yield 500 square feet worth of coverage) and it is now readily available at HomeDepot.com and Lowes.com. This sealer only costs about $0.10 per square foot per application; considering the cost to replace concrete is about $7.00 per square foot, sealing concrete with the 9500 is a worthwhile investment.
The Siloxa-Tek 8505 is a revolutionary product that is able to repel salts (including deicing salts), oils and stains from household products, automobiles, bbq grills, leaves and more. Of a silane/siloxane chemistry with an added proprietary component this product is unrivaled when it comes to sealing driveways, warehouses and patios to name a few. This product leaves a completely clear, natural finish so once you apply it, you wont even know it is there except when water, and fluids are spilled on the surface and they bead right up like a newly waxed car.
A lot of manufacturers claim their products will “limit the penetration of stains”; however, this is different and must not be confused with a sealer that is formulated to actually repel stains and oil like the Siloxa-Tek 8505. The manufacturer would not give away the proprietary ingredient but we tested it in comparison to the products that claim to limit the penetration of stains and there is no comparison. The proprietary ingredient in the Siloxa-Tek 8505 is extremely effective and performs as described on the technical data sheets and the manufacturer is actually able to provide testing data on request.
This product is available in two variations, a water based version for residential applications and small commercial applications or a solvent based version for larger commercial applications. The water based version is available in a ready to use formulation or a ultra concentrated version (both are readily available for purchase through Lowes.com and if you prefer, formally known as the Siloxa-Tek 8500 OR, The Home Depot.com carries the ready to use version). The ready to use product will cover 125 sq. ft. per container for both applications and the ultra concentrated product will cover 625 sq. ft. per container for both applications. If you are looking for industrial or commercial use of this product, it is also available in a solvent based version is called Siloxa-Tek 8510 and is available through the manufacturer in 1 gallon, 5 gallon bucket or drum quantities.
When it comes to application it could not be easier to apply. A garden variety sprayer, or nap paint roller is recommended. Two coats are highly recommended and upon talking to the manufacturer they essentially require it. The coats are applied wet-on-wet. What wet-on-wet means is that the second coat is applied before the first coat has dried. Because the product is so hydrophobic if you try to apply the second coat after the first coat has dried the first coat will try to repel the second coat. However, if you apply the second coat while the first coat is still wet you are able to get the product to penetrate as deep as possible and ensure the longest lasting performance. A good rule of thumb is to apply a first coat to a 500 square foot section and go back and apply the second coat to the same 500 square foot section and then move on to the next section and apply a first coat, then second coat. (You can walk on the first coat to apply the second coat, since it is a natural finish product it will not leave footprints).
What we love most about this product is that it does not need to be reapplied every year or even every few years but the product has a lifespan of up to 10 years before needing to apply another 2 coats. We recently came across this distributor, Concrete Sealer Solutions, which has the ultra concentrated version on sale for $15 less than Lowes! Since the product is concentrated, the price breaks down to about $50 per gallon, quite a bargain when it comes to protecting a concrete driveway from spalling, pitting, cracking, deicing salts, oil, auto fluids and leaf staining.
After over 30 hours of researching more than 60 concrete sealers and testing and evaluating seven of them, our results are found below. We found that the Siloxa-Tek 8500 is best for most people. Its made of high quality silanes and siloxanes with a 40 percent solids content, so it’s active ingredients are stronger, less watered down and approved by the Department of Transportation. The 8500 sealer leaves a natural finish without any artificial luster or sheen leaving a natural, protected surface without ever fading.
Why you should trust us
We have worked in the construction industry for more than 20 years. We’ve reviewed countless sealer products with our conclusions posted throughout this site. For this guide we also talked to a number of experts about what they look for when sealing any concrete application.
The American Concrete Institute provided us with resources about terminology and the industry, and we gained insight from magazines such as Concrete Decor, Concrete Construction and For Construction Pros as to which products were popular among contractors.
To determine the longevity of sealers we relied heavily on customer reviews from Home Depot, Lowes and Amazon.
The difference between penetrating sealers, decorative coating and durable coatings
If you’re purchasing a concrete sealer for the first time or you’re due to reapply, its helpful to know the meaning behind some basic terms – including penetrating sealer, decorative coating and durable coating to ensure you get the appropriate product.
Penetrating sealers: Penetrating sealers penetrate into the concrete to form a chemical barrier that protects against water, moisture and deicing salts. They usually leave a natural finish without changing the surface appearance and most products are breathable allowing for vapors to escape. They are more frequently used in exterior applications to protect against the harsh elements. A penetrating sealer is your best choice if you are looking to protect your application from deicing salts, freeze-thaw cycles and water without changing the surface appearance or feel of the concrete. A penetrating sealer has a long lifespan and typically requires reapplication after five plus years of service life.
Decorative coatings: Decorative coatings are typically of an acrylic chemistry available in both solvent and water based formulations. Available in a range of sheen levels they typically leave a satin or gloss finish changing the look, feel and texture of the concrete. They are great for enhancing colors and giving concrete the much desired wet look. Acrylics generally wear faster than penetrating sealers and usually require reapplication much sooner, typically every year if exposed to deicing salts. Decorative acrylic coatings are great at first leaving the concrete looking nice but tend to wear quickly and cost more in the long run with constant reapplication.
Durable coatings: Durable coatings build a protective film on the concrete surface, producing a hard, long-lasting abrasion and chemical resistant finish. Available in a variety of colors most durable coatings leave a gloss finish. Durable coatings are harder and last longer than decorative coatings. Because durable coatings may yellow with exposure to UV radiation they are limited to interior use.
How we picked and tested
Manufacturers offer penetrating sealers, decorative coatings and durable coatings but we’ve focused our selection on penetrating sealers due to their longevity, versatility, appearance and practicality.
Our testers were drawn to the natural finish of penetrating sealers. We aren’t alone in that assessment, as many of our experts agree. A Concrete Decor article titled, “Use of Penetrating Sealers is on the Rise” published in January of 2017 states, “The decorative industry grew up on the “one size fits all” high-gloss sealer which was the go-to coating for decades. While high gloss is still widely used, low-gloss and natural finishes in the decorative concrete industry have been gaining momentum as homeowners, architects and designers seek more ecofriendly, green and natural-looking sealing options.”
Aside from its appearance, penetrating sealers offer greater durability and are less prone to water absorption and deicing salt damage than decorative coatings.
Ultimately you want a sealer that provides water repellency to keep out any salts, mold/mildew, efflorescence and dirt, and will have a long life span. We found that in penetrating sealers with a silane/siloxane chemistry.
In our research, we found that more inexpensive penetrating sealers suffered in quality due to low solids content and most commercial products were exorbitantly priced. We prioritized finding a high quality sealer that was both durable and had a high solids content at a reasonable price.
According to our experts, the best penetrating concrete sealers are resistant to water, chloride absorption and staining but clear enough to not change the look or feel of the concrete. The Concrete Decor article mentioned above states, “While relatively new to the decorative industry, penetrating sealers have been used successfully in other markets for decades. Originally developed for the stone, masonry and concrete flatwork industry, penetrating sealers primarily resist water and stains, while not changing the substrate’s appearance. Their primary functions have been salt and acid resistance, efflorescence control and water resistance.”
Concrete Construction noted that, “When applied properly, penetrating sealers can serve as chloride screens and dampproofing to improve durability against destructive corrosion of embedded reinforcement and damage from freezing and thawing.”
Decorative sealers can be beautiful to look at but they’re also more likely to fade over time. For this reason we limited our search to products with a natural finish that do not need to be reapplied as frequently.
Overall we preferred sealers with proven longevity that were highly reviewed with excellent water beading characteristics.
We searched for sealers that are available online which allows the consumer freedom to order and have them shipped to a home or business versus having to shop around and find a distributor that carries the product in stock. Ideally we wanted sealers that were not only conveniently available but offered excellent performance. At the very minimum we felt each sealer should be composed of a 20% silane/siloxane chemistry. We were able to rule out any sealers that were too watered down or did not have enough active ingredients. Sealers that offered additional oil and stain repellency were viewed as a nice bonus, but were not a required factor in our selection.
A note on penetrating sealers. Though plenty of penetrating sealers are available our research showed that homeowners often regret purchasing a penetrating sealer that did not offer any sort of water repellency, such as a penetrating silicate densifier. These sealers simply harden the concrete but offer no water and stain repellency. They are inexpensive, but likewise they don’t offer the full benefits of a silane/siloxane penetrating sealer. Because of this we prioritized finding products that were penetrating and hydrophobic impregnating sealers.
After considering over 60 concrete sealing products, we evaluated and tested seven. We applied and examined each product to check for a clear, natural finish. We tested for abrasions, salt exposure and water absorption and we also compared the application techniques for ease of use. Finally we asked testers to check for mold, mildew growth and efflorescence deposits.
Our pick: Our testers like the ease of use and lack of maintenance of the Siloxa-Tek 8500 of all the sealers we tried. The product is easy enough to use so a professional is not needed to apply it. The Siloxa-Tek 8500 is also available as a concentrate which was lacking from the other sealers we tested. The type of silane, one of the chemical components, that is used in the product also gives the Siloxa-Tek 8500 a longer performance life, making it more stable and less volatile.
The sealer not only uses quality silanes (octyltriethoxysilane) but it is a well formulated blend of silane and siloxane. Water was not absorbed by the concrete whatsoever during the water absorption test; in fact we were able to move the beaded water across the concrete and even then it was not absorbed.
Also the sealer is available in a ready to use or concentrate version so you have the freedom to choose if you want to pay less to do a little extra work or pay a little more for the ease of convenience. The concentrate allows you to pay less in shipping since a one gallon of concentrate will make a five gallon pail of sealer, which wasn’t a possibility with some of the other sealers we looked at. This sealer is sold through Home Depot Lowes and Amazon, and Ghostshield is a brand that’s been around for years.
Flaws but not deal breakers
The only drawback to the Siloxa-Tek 8500 is that it does not repel stains such as oil and grease. We detected these minor imperfections when the Siloxa-Tek 8500 was applied to a garage floor. Some of our testers found that if you prefer stain protection the 8500’s counterpart, the Siloxa-Tek 8505, is resistant to staining. Also the Siloxa-Tek 8500 is more expensive than some of the other sealers we reviewed, but the quality and longevity were unsurpassed making it a worthwhile investment.
Long-term test notes
After fifteen months of exposure to the elements, two freeze-thaw cycles and two winter seasons, we still highly recommend it. We did not have any visible cracking, spalling or deicing salt damage on driveway applications. Though we haven’t tested the product for a full five to ten years like the manufacturer claims it will work for, we haven’t experienced any major issues ourselves but we’ll continue to long-term test to see if any problems arise.
Though we like the Siloxa-Tek 8500 best, if you prefer something less expensive and a product that is available on store shelves we recommend Rustoleum Okon S-40. This sealer is also a 40% silane/siloxane, penetrating sealer. It is not available concentrated, but it has a nice price point for a 40% formula. This sealer comes with the option to purchase online or in some retail store outlets.
The S-40 has proven longevity, with one reviewer on the Home Depot site saying “This product is 40% silane/siloxane and is the best deal on an active ingredient basis. Most of the other products out there are just watered down versions with only 5%-20% active ingredients. S-20 was the next best deal I could find. Be sure to look at the concentration of ingredients on the Spec sheet so that you don’t end up just buying water.” We’re confident this will remain an effective and viable option for sealing concrete for years to come.
Eagle Natural Seal had a lesser active ingredient content than our other picks but there is no denying its cost effective price point. Ultimately most of our testers found the sealer to be a easy to apply solution though it did not produce as significant of a water bead effect as some of the other products we tested.
Is there such thing as an oil repellent concrete sealer? The answer is yes. There are two different types of oil repellent products for concrete: coatings and penetrating sealers. Can a penetrating sealer stop oil? The answer is yes. But not all penetrating sealers can stop oil. Penetrating concrete sealers like silicates, siliconates, and silane/siloxanes will not be resistant to oil on their own. In order for a penetrating sealer to resist staining it needs to possess a fluorocarbon.
What is a fluorocarbon? Toefco writes a great article explaining the introduction of fluorocarbons: “A fluorocarbon is a chemical compound that contains many strong carbon-fluoride bonds. The fluorine in a fluorocarbon is electrically negative, which gives it the property of not bonding easily with other materials. That’s what makes a fluorocarbon non-stick. A fluorocarbon is an umbrella term, and it includes many other products with trade names that you may have heard of, including Teflon. The first fluorocarbons were developed in the 1930s by Dupont, but hundreds of variations now exist.”
By combining penetrating sealer technology with these fluorocarbons manufacturers are able to create oil repellent penetrating concrete sealers. If you are looking for testing data to verify the effectiveness of penetrating sealers with oil protection, the PCI (Paint and Coating Industry) publication evaluated the effectiveness of penetrating sealers formulated with fluorocarbons from 3M. They put the products through vigorous tests and concluded that penetrating sealers with fluorocarbons demonstrate “significant improvements to stain resistance and oil repellency and good retention of performance through repeated cleaning and weathering. And such they can be considered as a stain protection solution for a wide range of surfaces and environments.”
Should I use a coating or a penetrating sealer to stop oil? Acrylic coatings are available in water based or solvent based versions and although they may help to repel oil by coating the surface of the concrete they do not have a very long life span and usually need to be reapplied every year, especially if they are exposed to deicing salts. Urethane coatings will repel oil and are highly resistant to chemicals; however, they can only be used indoors and they will leave more of a gloss finish. You also usually need to grind or etch the floor prior to applying a urethane coating. We really like penetrating sealers for for a few reasons. 1. They will never yellow, fade or peel. 2. They leave a natural finish and will not change the look of the concrete. 3. They are deicing salt resistant. 4. They have a lifespan of 5+ years. 5. If mixed with a fluorocarbon they are resistant to staining. To answer the question, Can a sealer reduce oil stains? Yes, a penetrating sealer can reduce oil stains if a fluorocarbon is used in conjunction with the formulation.
How can I stop oil from staining my concrete? Our recommendation is to use a penetrating sealer with a fluorocarbon, some examples are below.
- Ghostshield Siloxa-Tek 8510: A clear, solvent-based, silane, stain resistant water, salt and oil repellent penetrating sealer. It will protect against deicing salts, oils, grease and food. Retails for $399 per 5 gallon pail.
- BASF’s Masterprotect 1001: A clear, solvent based, silane, penetrating water repellent sealer with an oleophobic additive. It is frequently used in commercial applications by contractors and retails for $420 per 5 gallon pail.
- Prosoco SLX 100: A clear, solvent based, silane, water & oil repellent that combines water and oil repellency on most substrates to prevent staining by waterborne and oily substances. Retails for $1090 per 5 gallon pail.
When it comes to answering the question of what the best concrete sealer is, its hard to pin point one type of sealer for all applications. There are a lot of factors that go into choosing a sealer including application (driveway, patio, etc.), substrate (concrete, brick, masonry) and functionality (salt repellent, waterpoofer, oil repellent, decorative).
Below is a quick reference guide that highlights common applications, substrates and functionalities:
Concrete Driveway: If you are looking for deicing salt protection use a silane/siloxane blended sealer. If you are looking for oil and staining protection use a silane/siloxane with a stain protector like the Siloxa-Tek 8505.
Concrete Basement: If you have active moisture or water issues it is best to use a two step application by first using a densifying primer of a lithium silicate carrier, followed by a penetrating silane/siloxane product. If you do not have active moisture issues and are looking to proactively seal, use this fantastic all-in-one product found at homedepot.com
Concrete Blocks/Cinderblocks: Because of the porous nature of the concrete cinderblocks it is best to apply three to four coats of a penetrating silane/siloxane sealer.
Stone/Stucco/Slate/Bricks: Stone, stucco, slate and bricks are best protected using a penetrating, natural finish silane/siloxane sealer that will not encapsulate the substrate so it is still able to breathe.
Patio/Pavers/Pool Deck: When sealing a patio, pavers or pool deck it is best to first figure out the desired finish if you are looking for a natural/clear finish, low sheen or wet look/gloss. If you are sealing a salt water pool a silane/siloxane blend is going to be the best option to keep the pool deck from spalling and pitting. Keep in mind that the natural finish products are penetrating and give the longest lasting, best protection. Whereas low sheen and gloss finishes typically need to be reapplied on a more frequent basis.
Natural/Clear Finish: Penetrating silane/siloxane sealer
Low Sheen: Water based acrylic
Wet Look/Gloss: Solvent based acrylic
Waterproofing/Salt Protection: A penetrating silane/siloxane like this one that gets great reviews from HomeDepot.com
Oil/Staining Protection: Lowes.com offers this product in a concentrate so you get to control the mixing and application. It’s great to protect driveways from oil stains and leaf staining and backyard patios from BBQ grill and food stains.