"Seal The Deal-Part 2" - Sealers for Concrete Countertops

Let’s continue our discussion about choosing concrete sealers for concrete countertops. Generally, we’ve found that the best sealer that is a happy medium between cost, appearance, and protection is either a water or solvent based polyurethane.

black island countertop with a high gloss finish

Polyurethanes offer good scratch and heat resistance and excellent stain resistance which is why we use them a lot. These are our favorite as they are very durable and resistant to virtually all food stains due to being completely impermeable, a characteristic they share with epoxy sealers.

By impermeable we mean that a liquid will not penetrate through the sealer no matter how long the liquid sits on it. This of course depends on the type of liquid.

Industrial solvents can sometimes soften and penetrate a polyurethane but you don’t normally have those in kitchens or bathrooms. It also depends on whether the sealer has been compromised — which means no cutting on it!

closeup of a black concrete countertop featuring a stone edge with a high gloss finish.

Polyurethane sealers come in two types, water or solvent based. The solvent based significantly deepen the color of the countertop surface and leave it with a very high gloss finish as you can see in these pictures.

Water based polyurethanes have a more matte, natural-looking finish, and generally only slightly darken the color of the concrete.

Polyurethane is easier and less expensive to apply than epoxy sealers and simpler to touchup if there’s any damage. They are actually more scratch resistant than epoxies – ironically, we often apply a protective polyurethane coat over epoxy to help protect it.

However, just like epoxy sealers, placing very hot pans or cutting directly on them can damage the finish. Overall, they are an excellent choice for the average home concrete countertop and we do use them often for commercial settings such as bars and restaurants.

inside concrete countertop

We do have other sealer types available depending on what our clients want. The project pictured above was done at a “Chuy’s” Mexican restaurant in Fort Worth, TX. We first poured a bar countertop and then sealed it with a clear epoxy.

These countertops are in a very tough environment. They have everything from spilled beer to searing hot fajita plates on them, so we used one of the toughest concrete sealers there is to protect them — an epoxy based sealer.

Epoxy sealers will deepen the color of the countertop and usually leave it with a high gloss finish. They are very tough and really protect the concrete from staining and general abuse but they’re the hardest to touchup of all the sealer options.

They normally have two components, a part A and part B, that are mixed together in a specific ratio and through a chemical reaction begin to harden. The trick is to get it all down, smoothed out, bubble free, and looking good before it hardens too much.

Epoxy sealers also have “build,” i.e., they go down much thicker than other types of sealers. It’s this thickness that gives them the really “wet look”. We often apply these in restaurants since they want that deep, spilled water look for their countertops.

A downside to this type of sealer is cost, the material is much more expensive than other options and requires a high level of expertise to put down properly. It can also take a long time to dry between coats.

another view of concrete countertop with epoxy sealer

The most economical sealer for concrete countertops is an acrylic. This type of sealer is very easy to apply and touchup if damaged, with the trade-off being that they are softer and less stain resistant than polyurethane or epoxy sealers.

In fact, acrylic sealers, whether solvent or water based, are semi permeable, i.e., they “breathe.” This means that if something spills on them, it won’t get through to the concrete immediately, but over time (usually less than 24 hours) it can etch or stain the concrete underneath.

While we’ve applied acrylic sealers to many countertops, we always advise our clients that they have to be vigilant about cleaning spills or some staining / etching can occur.

closeup view of countertop edge
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