Q: What are the different types of concrete sealers, and which one is right for me?
A: There are thousands of formulas out there, and there are literally 3 or 4 new concrete sealer companies appearing on the web each week. But, to help you sort through it all, you should know there are only about seven main technologies in use today. They are: silane, silicate, siliconate, siloxane, silicone, acrylic, and polymer resins. The first three are considered penetrating concrete sealers and the last four are more coating based. Companies are constantly touting the "new" formula blend or surfactant technology that makes theirs better than the others. Some of those claims are true, others are pure marketing hype. In fact, some of those concrete sealer formulas don't work at all! I'm a tech rep at MightySeal and for fun I collect silicate formulas that do nothing to the concrete. Believe it or not, a couple of these formulas come from companies with "big long time warranty's" how do they do that? Read our FAQ on "The Warranty Game in concrete sealers.' For now, lets take a look at the seven most basic kinds of technologies and how they work.

Silicone concrete sealers, are inorganic-organic polymers with the chemical formula [R2SiO]n, where R = organic groups such as methyl, ethyl, and phenyl. As concrete sealers they may be touted as a penetrating sealer, and they do soak in somewhat, but they are more readily understood as coating based concrete sealers. As a rule silicones have great hydrophobic (water repellent) and oilophobic (oil repellent) properties. Sounds like a great concrete sealer right? Well, usually the answer is "no." Many companies using silicones will demo the product at a home show and the silicone's hydrophobic and oilophobic reactions wow the homeowners. But unfortunately what goes unseen is the LENGTH of life. As a rule, silicones are very short lived. They are UV unstable, and because they are more surface based they do not hold up well to abrasion. What this means is you should only consider silicones for vary specific uses. If you have a vertical surface that may be prone to graffiti, a constant maintenance of silicone can help make clean up a lot easier. Keep in mind, a removal of graffiti will require a reapplication of the sacrificial silicone sealer immediately upon clean up to maintain protection. You should also consider reapplication of a silicone concrete sealer every one to three years to maintain protective barriers. Horizontal surfaces will likely only last a few months, and less when exposed to UV radiation.

Silane concrete sealers are "generally, any silicon analogue of an alkane hydrocarbon. Silanes consist of a chain of silicon atoms covalently bound to hydrogen atoms. The general formula of a silane is SinH2n+2. Silanes tend to be less stable than their carbon analogues because the Si-Si bond has a strength slightly lower than the C-C bond. Oxygen decomposes silanes easily, because the silicon-oxygen bond is quite stable." What this means in layman's terms it that they soak into the concrete and do a fairly good job of sealing the concrete. However, the concrete must be saturated heavily with a high solid silane to achieve longer life. If heavy spread rates are used (50 to 80 sq ft per gallon) and secondary and tertiary applications at (75 to 150 sq ft per gal) are performed, then a significant seal can be achieved. If saturation of sealer occurs then you can expect decent oilophobic and hydrophobic responses (though seldom is water-beading the reaction.) If the concrete is sealed with a heavy application life spans of 5 to 8 years can be achieved. Some parking garage structures have used this approach, and many porous block walls have benefited from this technology. However, silanes have three significant draw backs. First the are hydrocarbon based and as such can allow chemical chains to remain active in the concrete. Upon disappation (after a year or so) or upon too light of application, this active chemical chain is looking for other chemistries with which to react. What this means is, a spill of another hydrocarbon such as oil, transmission fluid, gasoline, diesel fuel, or gasoline type products can result in a stain that permanently attaches to the remaining active chemical chain. This can produce a permanent stain in the concrete that can never be cleaned except through removal of the concrete. This makes silanes less attractive for stain resistance. What is more, to achieve any adequate seal a complete saturation of the concrete with the sealer must occur. Such a saturation will usually significantly darken or discolor the concrete for life. Silanes are not the way to go if you are concerned about preserving appearance to as natural state as possible. Finally, silane chemistry is fairly costly. In addition to the cost of the sealer, spread rates to achieve an adequate seal are often required at double or triple other technologies resulting in a much higher price. If your need is 5 to 8 years of hydrophobic and oilophobic response and you don't mind the potential for darkening or stains, and you have the budget to pay more at the beginning, a silane can make a good fit.

Silicate concrete sealer helps to significantly reduce porosity in most masonry products such as concrete, stucco, plasters. As a rule, they work by creating a chemical reaction with the excess CaOH in the concrete that permanently binds the silicates within the concrete making them far more wearable and water repellent. Silicates are sought out because what they do they do permanently to the concrete. In other words, the concrete must be worn away or removed to remove them. It is generally advised to apply only after initial cure has taken place (7 days or so depending on conditions).

Unfortunately, that is where the similarity in silicates end. There are as many silicate formulas as there are concrete sealer manufacturers. Silicates have been around for a number of years and continue to be used because they affect long term seal and changes to the concrete. Most silicates are a very small molecule, which means they must be built from the "bottom up" in the concrete. They seal by going very deep and that usually means you will have to use more sealer to build up if you want any topical protection. Figure 75 to 100 sq ft per gallon on broom finishes for most silicates. If you are using a silicate blend, like the MS07, to penetrate smooth toweled finishes, then usually you will want some type of agitation of the sealer to take place also. A blended formula can help you by helping the concrete to penetrate more easily, as in the MS07, or it can help keep things more near the surface. Choose the best blend for your application. If you are looking at sealing a smoother garage floor, basement floor or warehouse floor that has been power troweled, then use a blend like the MS07, if you are looking to harden and strengthen a more open broom type finish such as a bridge deck, parking garage or a powdery or weak concrete surface use the MS12.

Siliconate concrete sealer also significantly reduce porosity in concrete, stucco, plaster, and cementitous chemistries. Like the silicates they seal by forming a permanent chemical change in the concrete dissolving the calcium hydroxide, reacting with it and other alkalis to form a new - nonsoluable chemistry. However, they are usually a larger molecule, offering more surface protection. Hydrophobic response is more obvious in the siliconate family than in the silicate. The siliconates will usually bead water quite well, and they continue to resist water in the form of water sheeting for years there after. Because they are larger molecule, they usually can be spread farther - figure about 200 sq ft on average. Siliconate concrete sealers make an excellent call when your primary concerns are reducing moisture and freeze thaw damage and stains. They will dry flat and clear leaving concrete looking much like it did before the sealing process. They are also ideal because they can usually be used the day of the pour - as a cure and a seal. However, they leave behind no membrane (unless you have a blend). This is often preferable if you plan to paint, coat or do something else like tile later. The "cure" portion is accomplished by retarding the hydration process. The concrete will still be breathable, the MS1 allows approximately two percent vapor escape - meeting the requirements for breathable concrete. Use this technology of sealer when you want the most "bang for your buck" and you are going on poured walls, or broom type finishes. Stamped concrete may also be done so long as there is nothing that prohibits penetration. Power troweled surfaces may be treated, but MS07 will be much more effective over the long term. For basement type application, consider siliconates like the MS1 for the walls and a good silicate blended (MS07) to get through the smooth trowel floor. Siliconates also make excellent primers for cemetitious substrates. Use before painting stucco to keep moisture from soaking through the paint later. Use on basement walls or other concrete before painting to achieve a longer life paint. Use on sidewalks, driveways and etc, to keep cracking, stains, and freeze thaw damage down.

Siloxane concrete sealers are a derivative of silicone. See above for best uses and what to avoid.

Silane Siloxane concrete sealer blends - the idea behind this was to get the penetration of a silane and the topical protection of a siloxane or silicone. Unfortunately it has the weakness of both and not the strengths. We have decided not to offer this type of technology as we consider it a waste of your good money. To understand it better, look at the weakness of both the silanes and siloxanes and add them together. Not a good call.

Acrylic concrete sealers also vary widely in the industry. Most are a polymethyl methacrylate (PMMA) or poly(methyl 2-methylpropenoate) the synthetic polymer of methyl methacrylate suspended in water or a solvent based material. The down side of many is they are brittle, often will yellow or can delaminate with age. Mightyseal has a non-yellowing additive to prevent this. Choose a solvent base (assuming you still can most will be unable to ship next year 2007) if you want to achieve the darkest wet look possible. Waterborne acrylics will darken less but still give you that shiny look. Acrylics seal by forming a film over the surface of the concrete. Since they are coating based usually two coats will be preferable to one. Figure about 200 sq ft per gallon for first coat and 300 for the second coat. Two lighter coats works better than one heavy one for most coatings and that would be true of the MS3 also. More shine is achieved by adding more coats. Since you are coating the surface the harder the material the better - therefore look for a HIGH solid content. MS3 is 30% solid and the highest you can achieve in an acrylic sealer. Life span will vary on this type of sealer but most folks will see a need for reapplication in 3 to 6 years. Usually this sealer is applied with a roller, but many will use a sprayer and back roll only if necessary. When you think of an acrylic sealer think of it like a clear concrete acrylic paint. That is what they are, therefore you must allow adequate drying time, and since it is clear we cannot allow rain or dew to form on the surface during the early cure time. Usually you want at least 5 to 8 hrs before a rain or dew to cure... higher humidity levels will require longer drying times for acrylics. Use this one when you want a lower cost decorative, wet look, appearance on your concrete, pavers, stamped concrete or pool decks. If slip factor is a concern most will usually allow you to apply a light broadcast of sand or other aggregate just after the first coat - then follow up with a seal coat.

Polymer resin concrete sealer - see acrylic sealers above and epoxy/urethane sealers below for that is what is usually meant by a polymer resin sealers.

Epoxy and Urethane concrete sealers - sometimes when a polymer is mentioned what the person is trying to convey is an epoxy or urethane topical sealer. There are a huge number and variety of this kind of coating sealer. First generation and second generation epoxy compounds required a very thick surface build sometimes with aggregate thrown in for look or abrasion resistance. They are good when you need surface build or self leveling properties. However, that heavy of a product is prone to cracking and delamination and is notoriously expensive to put down.

Third and Fourth Generation Two part epoxy and urethanes were developed in answer to the complaints of the old, thick applications of years past. They provide high chemical and abrasion resistance without looking like a chunk of plastic on your concrete. It is now possible to get a very smooth look in a very long lasting product. Use these when your concerns are chemical resistance, abrasion resistance, and appearance. They tend to be higher priced but spread a lot farther than the older versions. Some today will go 400 sq ft per gallon! Mightyseal can help you select a system that will be perfect for your concrete countertop OR your heavy industrial floor. We can help you cover decorative concrete walkways or your garage service bay. How does resistance to sulfuric acid, brake fluid, gasoline, AND 400 degrees of heat sound? Take a closer look at our coatings section for more info here. ASTM test data varies on these type of products so always ask to look at the test data to see what you are really getting. Mightyseal only offers the strongest and longest in these products... for more info visit our coatings section and look at MSE and MSU products.

Linseed Oil concrete sealer - Many, many years ago folks would often "brew their own" concrete sealers from a mix of linseed oil and some solvent base such as kerosene or something else. Often these were a 25% mix of linseed oil with a 75% of kerosene or other solvents. This did "plug" the pores of cement fairly well, but because the linseed oil was more topical and subject to ultraviolet break down, the sealer would have to be reapplied each and every year. Some states would paint their bridge decks with this type of product up until as late as 2001. The EPA not only "frowns" on this highly flammable and dangerous approach to sealing, but if you contaminate the groundwater in your attempt to seal with this, they can fine you up to $10,000 for each occurrence. Linseed oil is very cheap, as is kerosene, however for this to be effective it must be reapplied each and every year. The downsides (besides being illegal) are: linseed oil will darken and permanently stain your concrete. It will become darker and more dirty looking with each application. As stated earlier the low cost is off set by the fact that you must redo this each and every year. After 2 or 3 years you usually would have invested as much as if you had done a proper concrete sealer. Migthyseal does not endorse this linseed oil approach to sealing in any way, it is VERY dangerous and you will be fined if someone calls the EPA.

Q: Which sealer is right for me?
A: It depends. We always suggest you start with the end in mind when picking a concrete sealer. Start by asking yourself, what do I need a concrete sealer to do for me? How long do I need it to last? Above we've listed all the basic formulas in use today, but if you need more help, check out the LEFT SIDE of our home page and click the picture that best describes your substrate.