"Seal The Deal" - Sealers For Concrete Countertops
What are the available choices for a concrete sealer for concrete countertops, and why do you even have to think about it? Concrete is naturally porous, any liquid spilling on it will be sucked right in unless a sealer blocks it.
Water isn’t much of a problem. It will temporarily darken the area and the concrete will revert to its original state when it dries. The problem is when other liquids like vinegar, lemon juice, oils, or wine are spilled on an unsealed surface. With some of the acidic liquids such as lemons these can actually “etch” the surface of the concrete and damage it. Oils can penetrate deeply into the concrete and not “dry out”, leaving a permanent stain. Depending on what type of sealer you choose, we can reduce or prevent these issues.
A concrete sealer for concrete countertops can be broken down into two basic camps: water based and solvent based. They’re pretty easy to tell apart just from appearance and smell. Water based sealers tend to be milky white and have a low odor. Solvent based concrete sealers are almost always completely clear and have a strong odor.
To make things even more confusing, sealers can also be categorized as topical or penetrating. Topical sealers form a “skin” on top of the concrete, preventing liquids from actually reaching the surface of the concrete. Penetrating sealers are wicked into the concrete and try to do the same by sealing the small concrete pores internally and from below the surface.
So which one is better? It really depends on your expectations. If stain resistance is your number one priority, the best concrete sealer for concrete countertops is a topical sealer. As these are applied onto the concrete, they tend to prevent liquids from penetrating into it. Keep in mind that different types of sealers offer different levels of protection (more on that later).
Depending on the type you select (epoxy, polyurethane, or acrylic), it can change the final appearance of the countertop. The same if you choose between a water or solvent based sealer. Water based tend to have a more matte, satin finish while solvent generally have a high gloss finish that darkens the concrete color (think of it like pouring water on a concrete floor; it gets a glossy, darker look).
If staining isn’t as big a deal for you then a good sealer choice for concrete countertops is going to be a penetrating sealer. These do not create a barrier on the surface of the concrete, instead these sealers penetrate deeply in it and seal off the capillaries and pores to prevent liquids from seeping in. The biggest advantage of these sealers is that placing super hot pans, cutting with knives, etc. won’t damage the sealer. It’s not on top of the surface (that doesn’t mean you can’t scratch the concrete itself, but that does take some trying).
Penetrating sealers have almost no effect on color or appearance, you get concrete as close to natural as possible but they are not as effective at stain resistance as the topical sealers, particularly against acidic liquids. Wine, lemon juice, oil, and other foods can etch or stain the countertops fairly quickly if you are not diligent in wiping them up. Why is this?
Topical sealers prevent contact with the concrete, no contact – no staining/etching as long as the sealer is not physically damaged. While a penetrating sealer also seals, it does so from below so liquids will work on the top of the concrete and though slowed by the closed off pores, eventually “chew” their way into it.
Just as an FYI, this black concrete tabletop was sealed with a matte polyurethane which is a topical sealer. It offers the best of both worlds – good to excellent stain resistance (again dependent on the type chosen) and good resistance to heat / wear and tear found in kitchen or bathroom environments while still maintaining the more “natural” look of concrete.
Also keep in mind, in spite of what the salesman promises, no granite, marble, stainless steel, Corian, Silestone, or Formica countertop is 100% stain / heat / scratch proof, they all will, just to differing degrees. We do offer high gloss versions of topical sealers as you’ll see in the next “Best of” project.