Concrete Floors, Penetrating Concrete Sealers & Densifiers

In a perfect world, moisture intrusion wouldn’t be a problem for any concrete floor. Unfortunately, even when all the proper steps are taken before the concrete is poured, moisture issues can come up. If moisture is the only challenge you’re facing, there are many products you can choose to combat it, such as topical sealers and crystalline waterproofing products. But if you’re trying to achieve multiple objectives — including moisture management — with just one product, a densifier may be just the thing you’re looking for.

When talking about densifiers, it is important to be clear about what a densifier is, and what it is not. It is not a moisture-proofer or a waterproofer or a water repellant.

Steve Erickson, president of DynaCrete USA, reports that waterproofing materials are often confused with densifiers. They are also confused with wear coats, he adds.

Rather than being products that plug off the naturally occurring capillaries in the surface of concrete, densifiers penetrate and become part of the concrete matrix. They are more than a membrane or topical sealer.

As Phil Smith, vice president and technical director of L&M Construction Chemicals Inc., explains, 15 percent to 20 percent of portland cement forms calcium hydroxide as a by-product of the hydration process. This by-product is soft and does not contribute to the structural integrity of the concrete, so the idea behind densifiers “is to take this material that has no structural value and marry it to a chemical substance that can convert it into a material that has structural value.”

Densifiers penetrate into concrete, then chemically react with the calcium hydroxide within the surface of the concrete. This chemical interaction creates yet another by-product that fills and closes the pores in the concrete, thereby producing a denser surface.

It’s this reduced porosity in the concrete that slows moisture penetration, says Jim Sist, president of ChemTec International Inc. It also does much more, but we’ll get to that shortly.