Article No: 22
Caring for concrete countertops
By: KARIN MARIE
Every unique feature in a home, like fine wood or a backyard pond, needs special care. And concrete countertops are no exception.
"Like any surface, concrete requires maintenance," says Bert Adams of sealer and cleaner manufacturer Glaze 'N Seal.
Concrete's characteristics and the ways it interacts with other substances determine how to care for it. With concrete, like all kitchen countertops, the primary goal is to protect the surface from damage by food and cooking equipment.
There are two basic types of care for concrete countertops — general cleaning and the periodic application of a protective sealer.
Characteristics of concrete counters
Concrete is a porous material that absorbs liquid. Citrus juices, vinegar, oils, red wine and berry juice can stain or damage the surface. Acidic substances, which include citrus and vinegar, create light spots and etch concrete. Cooking oils, red wine and berries leave dark stains.
Homeowners should be careful about setting unglazed ceramics on their counters, says Jennifer Mair of Oakland, Calif.-based Concrete Works Studio. "Ceramics, like terra cotta, compete with the concrete for minerals. It leaches minerals out of the concrete, leaving a residue and eventually lightening the concrete."
Since most problems are caused by concrete coming in contact with a damaging substance, it's important to keep a barrier between the two. This involves applying a sealer to the concrete to make it more resistant to such substances.
Regardless of how careful a homeowner is with concrete counters, over time they acquire a patina. Some homeowners, anxious to "patina-ize" their counters, try to help it along. "Sometimes people leave stuff on their counters on purpose," Mair says.
"If you want to create a patina, then stains contribute to the aging and beauty," says Kelly Carr of Silver Spring, Md.-based Concrete Jungle. "People who want their countertops to have the look of an old European bar should understand that those surfaces have had stuff spilled on them for hundreds of years."
Mair, whose own concrete counters sport a few spots, looks forward to the day when her counters acquire a patina. "I'm open to the fact that concrete is a porous material and live with that," she says. "I expect a patina over time."
Sealers are used to protect concrete countertops from kitchen culprits like acids and oils. Two types of sealers are commonly used on concrete counters. The first is a penetrating sealer that flows into the concrete's pores and seals them. The other type leaves a coating or film on top of the concrete, creating a physical barrier between the concrete and contaminants.
A penetrating sealer is often applied by the manufacturer, but is sometimes applied by the homeowner. Coating sealers, such as a wax, are usually applied by the homeowner on a regular basis. While these supply a high level of protection, they are not impermeable.
"Sealers make the concrete stain-resistant, but not stain-proof," Carr says.
There is no rule about how often to apply sealer. This is determined instead by factors such as the amount of use a counter receives or the level of protection homeowners want. Counters can be given a coat of surface sealer once a month for more protection, or just once every few months.
"The penetrating sealer protects the counter and the wax protects the sealer," Mair says. "Keeping the countertops waxed will go a long way to protect the sealer."
Before applying a surface sealer, the counter should be clean, dry and free of old contaminants. "Be sure to read the label and follow the manufacturer's instructions," Adams says. "I suggest doing a test patch in an out-of-the-way spot so you can see what the sealer will look like. Let it cure for a couple of days, then test it with a variety of contaminants."
Sealers that coat the surface of counters repel liquids, causing them to bead up. "When liquids don't bead up anymore, it's time to reseal," Mair says.
Another way to tell counters need resealing, Adams says, is to watch for worn spots. "You'll see that the sealer is wearing down, similar to worn spots on the finish of a wood floor."
Concrete countertops commonly develop hairline cracks. While these tiny cracks don't signal structural damage nor create a void, they are more susceptible to absorbing liquid and should be sealed more often.
Sealers come in a variety of types and finishes — liquid, paste wax and spray on, semi-gloss, natural and wet-look. Experts also recommend products not specifically designed for concrete use, like Butchers Wax. Carr recommends a grout and tile sealer and a cleaner that contains a small amount of sealer. "It's good to use because it doesn't remove any sealer," he says.
With concrete countertops, it's important to stay on top of the spills. "Clean spills as soon as possible," Adams says. "The sealer is buying you time. It provides protection, but doesn't make the counter indestructible."
Also avoid setting hot pans and dishes on counters as they can damage the sealer. And counters should not be used as a cutting board. Knives can cut through the sealer, creating weak spots. "It won't damage the concrete, but it will dull your knives," Mair says.
Mild soap in warm water makes a good cleaner for concrete counters. Use a dishrag or sponge and avoid scouring pads. Cleaners containing abrasives, bleach and ammonia should not be used since they can damage the sealers.
"A neutral pH cleaner can be used since it won't damage the sealer," Adams says. "You can usually find these in a tile store."
Caring for concrete counters is easy when you know what to expect. "Something for people to understand is that they are buying concrete, not something made in a lab. It's a commonplace substance used in an artistic way," Carr says.
Giving concrete countertops the appropriate care ensures they stay beautiful for years.