The market for concrete sealers is crowded with products all professing the same level of protection, quality, and benefits. For consumers well versed in concrete, as well as for homeowners who just want to protect their homes, the plenitude of information is overwhelming. To make matters worse, there aren’t really any websites unconnected to companies that sell concrete sealers that give reliable information. Instead, most websites only offer information that directly supports their product, which may or may not be the best actual advice.
Before you can begin to search for the appropriate concrete sealer, you must have a good understanding of your project. Maybe your last house was musty and all-around gross, and you want to protect the basement in your new home. Maybe you bought a home and paved the driveway, only to have cracks appear after a few months. Or maybe you’re recovering from a massive lawsuit after one of your children’s friends tripped over a crack in your pool deck, sliding on the slippery concrete and breaking an arm – wouldn’t you want to know how to prevent this at your new home (which, of course, also has a pool because you just can’t help yourself)? Whatever the project, there is always a better, and a worse, choice in concrete sealer.
Concrete sealers can be, for our basic purposes, divided into two rough categories: surface and penetrating sealers. Surface sealers are solutions whose chemical particles pool on the surface, rather than penetrating past the small pores on the surface of concrete. The particles are too large to fit through those holes (as opposed to penetrating sealers, which we’ll get to later), remaining on the surface to be brushed or sprayed out.
There are a few different types of surface sealers. The most common are acrylic-based sealers, which are frequently used for more decorative concrete, like driveways or patios made up of pavers. For the homeowner who needs to seal his/her pool deck, an acrylic sealer is the best choice, as many of the higher quality products offer slip resistance in addition to the water and UV resistance that are the product’s primary task. Acrylic sealers themselves come in two forms: water-based and solvent-based. The water-based sealers are safer for the environment and safer for the person applying the substance. They have low to nonexistent VOC (Volatile Organic Compound) contents, which basically just means they are safer for the environment. The solvent-based acrylic sealers are potentially more harmful with higher VOC contents, though they have the benefits of lasting longer with a high gloss shine (compared to the matte appearance of water-based sealers). If you opt to use a solvent-based sealer, you have to make sure it is legal in your state while taking all necessary precautions (e.g. proper ventilation mask, nothing flammable nearby, proper clothing, etc.). Some sealers are so dangerous that their fumes can harm your skin, introducing dangerous chemicals into your nervous system that could result in severe health problems.
If you have a rough concrete surface that is not necessarily as delicate as decorative concrete, you can use epoxies. Epoxy sealers are another type of surface sealer, better suited to rough surfaces. They are also the best choice if you want to add color to your concrete. While you can certainly use an epoxy on its own as a standalone product, they work best when they are part of an epoxy system.
Epoxy systems are made up of one or two epoxy coats, covered by a urethane or polyaspartic topcoat. Urethanes and polyaspartics are two other types of surface sealers, similar to epoxies. A typical epoxy system will consist of an epoxy coating directly on the substrate (which is just fancy industry-speak for the concrete), which functions much like an acrylic sealer: large particles pool on the surface to be spread out for maximum protection. Then, another epoxy is often used. This layer will be applied after the previous layer has dried, giving extra protection to the concrete. It is at this stage that you can add color chips to make your floors more visually appealing, which is one of the biggest benefits to epoxy systems. Finally, after the epoxy base coats, there is a polyurethane/urethane topcoat, which seals the floor to enhance resistance to water, spillage, and abrasion.
The biggest difference between traditional polyurethanes and polyaspartics is that the latter dry far more quickly than polyurethanes. Large retail stores will often opt to use epoxy floor systems with polyaspartic topcoats to protect their floors because the installation can be done overnight, ensuring that they can go back to business the next day without a hitch. Epoxy floor systems are also commonly found in airports: frequent flyers will surely recall oddly smooth floors connecting terminals, filled with chips of paint and quartz.
The second broad type of concrete sealers is the penetrating sealer. Penetrating sealers are one of the most effective methods of protecting concrete basements, driveways, and garage floors. Instead of pooling on the surface of the concrete like surface sealers, penetrating sealers consist of particles of chemical small enough to pass through the tiny pores on the surface of the concrete.
Concrete itself is filled with tiny pores and air bubbles, which is a direct and natural result of its creation – the binding of Portland cement and water occurs through a process called hydration, which results in innumerable tiny pores. Penetrating sealers take advantage of these pores and air pockets to react chemically within the material, leading to a fundamental and permanent change in the concrete. The particles – most commonly silicates, siliconates, or silicate/siliconate blends, depending on the concrete sealer – react with the free lime and calcium that remain unbonded within the concrete. The reactions result in the formation of calcium silicate hydrate (CSH), which helps fill cracks, capillaries, and pores within the concrete. This, in turn, densifies the concrete, making it stronger and more resistant to the passage of water and vapors through the concrete (and, subsequently, into your home). It is important to note, however, that concrete treated with a quality penetrating sealer will still retain its ability to breathe, allowing moisture and vapor to exit the slab, which is crucial to its strength and durability.
Penetrating sealers typically consist of chemicals, made up of particles of silicates, siliconates, silicate/siliconate blends, and silane/siloxanes, which are housed in a sodium or lithium carrier and suspended in a water- or solvent-based liquid. The discussion about water- or solvent-based sealers is more or less the same for penetrating sealers as it is, above, for surface sealers. The bigger difference with penetrating sealers is whether to use silicates, siliconates, or any of the other types of particles.
Sodium carriers are far more common than lithium carriers, but they are not as effective methods of transportation. If you live in a colder climate marked by harsh winters, the plow trucks will all lay down salt to help clear the roads of ice. If you live in a location like this, it is much better to use a lithium silicate product. If you opt to use a sodium silicate, you risk the introduction of too much sodium (because of the excess salt your car picks up on the road and brings back to your garage/driveway in the winter) into your concrete, which can lead to disastrous harm. To avoid this costly scenario, it is much more advisable to use a lithium sealer, which even offers a slightly better level of protection.
As for the particles, silicates are by far the most common, and the differences between all of them are mostly academic and don’t have too much effect at a basic level. Silane/siloxane sealers, however, differ the most from the others. Instead of reacting within the concrete to form CSH, they deposit a hardened form of silane/siloxane into the material, performing more or less the same function as the other penetrating sealers. Both types of penetrating sealers are effective, but silane/siloxanes are often easier to apply, making them better for those who lack technical experience.
Ultimately, concrete sealers are a crucial addition to every concrete project. Nobody should buy a house, build a foundation, or install a pool/driveway/garage/etc. without treating the concrete immediately after it is ready. The problems that can arise from poorly protected concrete can cost incredible amounts of money, which seems silly when most concrete sealers are not exorbitantly expensive for the lifetime protection they offer. While the research may seem daunting, hopefully articles like this one, as well as various other forums and resources, will serve to help you determine the proper choice of concrete sealer for your specific process. As always, feel free to visit concretesealerreviews.com, posting questions and comments to help yourself and others like you, all wanting to protect our concrete.