Feature Article: Concrete Sealers





Concrete Sealers
by Sue Marquette Poremba

When it comes to sealers, it seems there are no absolutes.

One of the questions most often asked by customers when buying a sealer is how long it will last. The answer will vary, says Chris Sullivan, vice president of sales and marketing at ChemSystems Inc. "It comes down to the environment you are in," he says. "One of the reason sealers wear down has to do with microscopic grit particles. Mats and throw rugs can extend the life of a sealer considerably."

The difference between a topical and penetrating sealer can also be a bit of a gray area, says Sullivan. A portion of the topical sealer will penetrate into the substrate, he says, but in general, the topical sealer acts as a membrane. "Most of what's left after the sealer is applied, the resin, forms a protective coating on the concrete," Sullivan says.

On the other hand, with a penetrating sealer, 100 percent of the product will be below the surface, he says. "It doesn't change the color or any of the characteristics of the concrete. Instead, it fills the (concrete) from the inside."

Topical sealers tend to fall into three categories: acrylics, polycompounds (such as polyurethanes and polyureas), and epoxies. Topicals are used for durability and aesthetics.

Acrylics are the most popular topical sealers. They are used for economical reasons as well as ease of application, maintenance and repair, says Todd Winters, president of Surface Koatings. "While they don't last as long as urethanes or epoxies, they can be used for interior or exterior, on regular slabs or on decorative concrete," he explains. "The polycompounds can be used interior or exterior, but they require more preparation to apply and are harder to maintain and repair. However, they have the best moisture resistance. Epoxies are used primarily on interior applications."

Penetrating sealers usually provide resistance to something, such as water, grease or other contamination. They are usually made up of silanes, silicates, or silicone products. Whereas silicates are often used to seal interior colored concrete, Winters says, silanes are used as both interior and exterior sealers. Penetrating sealers can be used on countertops to help repel water and oil.

Every application is different, adds Steve Kroo of Concrete Jungle Distribution, based in Northridge, Calif. Start with what the look is, he says, then consider the intended use. "We always ask if this is a dirty environment, like the kitchen where there is food or the bathroom where there is makeup, and in those cases we use an epoxy or a poly because we want to protect from stains. But if it is a fireplace mantle, you can use just about any sealer or not even use a sealer at all. With exterior rocks, like waterfalls, you use a thin penetrating sealer with no shine."

When customers ask about concrete sealers, Sullivan has come up with an acronym to help guide them: SAP, which stands for safety, appearance and performance. "This can lead to good questions for clients to ask," says Sullivan. "Such as safety. Do we need to make sure the building is unoccupied when we apply it, or is it water-based system with no odor at all? Is it flammable? Does it meet federal or state guidelines for friction?"

Customers should also want to know what the sealer will look like after it is applied. "Sealers range from pure matte to ultra-high gloss," says Sullivan. "There is a rating system from zero to one hundred that rates the level of gloss."

Finally, he says, consider the level of performance. Where the sealer is being used, how it is being used, and the amount of traffic that will cross the concrete are all things to take into consideration when determining what type of sealer to use.

Customers should know what they are trying to accomplish with the sealer before coming into the store, says Gary Henry, business communication specialist at Prosoco Inc. "Does he want the sealer just for protection or to offer both protection and color enhancement?"


Regulations and application
Because of environmental regulations, water-based sealers are becoming more standard around the country. California and the Northeast and Mid-Atlantic states regulate the volatile organic compound (VOC) levels in sealers and other products, and any products that exceed the legal limit aren't to be sold within those states.

However, while lowering VOC levels is good for the environment, it can decrease the effectiveness of concrete sealers. Water should bead on the concrete and not soak into it, Henry says. "The compounds in solvents have something to do with making the concrete water-repellent. So in some cases, the more you reduce the VOC, it impacts the effectiveness of the product."

Henry's company has developed a number of water-based sealers that protect concrete just fine, he says. "We also still sell solvent-based, just not to anyone in California." There are also solvent-based sealing products that are acceptable under even California's stringent restrictions. Kroo of Concrete Jungle observes that manufacturers are good about letting him know which products meet his state's VOC regulations.

Customers also want to know how much sealer they will need for each particular application. Water-based sealers usually deliver between 250 and 400 square feet of coat per gallon. An epoxy or another sealer that goes on thicker delivers about 200 to 250 square feet of coat per gallon. The experts agree that it is best to apply the sealer per the manufacturer's directions to get the most efficient use.

Henry recommends testing one small area of the surface to be sealed, letting it cure for 24 hours, and then dropping water on it. If the water beads, that layer is fine. If the water spreads or soaks in, more sealer will be needed. This test can help customers estimate how much sealer will be needed.

How a sealer is applied depends on the surface and the type of sealer. However, in general, acrylics are rolled on while anything water-based is sprayed. "Epoxies are always dumped on the floor and spread with a squeegee," says Kroo.

When applying penetrating sealers, Henry says, saturate the surface, wait a few minutes for the sealer to soak in, and then apply a second, lighter coat. "If you have any excess or pooling, broom it out or towel it up. As always, the best advice is to just follow the manufacturer's instructions."

High-tech tools or power equipment are rarely needed for sealer application. Sullivan says the only rental equipment anyone would need would be expensive, high-pressure sprayers, but the need for them is rare.

Instead, the accessories retailers should have on hand for sealer application include items such as lint-free rollers and roller covers, garden sprayers, brushes, tape, slip-on booties, and safety gear such as gloves and goggles.

Finally, back to the question of how long sealers last: Sullivan says exterior applications of topical sealers last on average one to three years, but interior applications can last as long as 10 years or more, depending on the environment. Penetrating sealers last only 12 to 16 months, he says, noting that most penetrating sealers have a chemical makeup that requires annual reapplication.