Caveat emptor:
Refinishing those concrete countertops in your kitchen won’t be cheap.
Q: We installed attractive concrete countertops in our kitchen 18 years ago. I admit I did not properly care for them, believing that kitchen counters would not require care. Especially next to the sink, the surface is pitted, which is unsightly and unhygienic. I promise to do better. But is there someone or some way to refinish them?
A: Your countertops are the “pressed” concrete type, said Bill Kulish, owner of Kulish Design Co. in Springfield, Va. Pressed concrete countertops are formed in a mold, upside down, using a stiff concrete mix. When the countertop is removed from the mold and flipped over, relatively big air gaps show on the surface. These are then filled with a concrete slurry that’s typically tinted a different color from the main mix. In your countertop, these gap fillers created the yellow accents.
Tim Seay, owner of Decorative Concrete of Virginia, said his company does do this work. But it’s not cheap. Even if a kitchen has relatively little countertop space, refinishing the counters usually runs about $2,000, Seay said. “It’s expensive because it’s a two- or threetrip deal,” he said.
It’s possible to resurface concrete without creating dust, by using water to turn the dust into a slurry. But spattering your kitchen with water and concrete slurry would make a mess. So, unless there is a way to remove the countertop and refinish it outside or in a shop, the crew would need to use dry grinders with vacuums. Even then, they would need to install plastic sheeting to confine any dust that the vacuum doesn’t trap. Your family probably wouldn’t be able to use the kitchen for several days.
The crew would start grinding with 50-grit abrasive, which is very coarse. Once they had ground down the concrete to the bottom of the pits, they would then go over it four more times with finer and finer abrasives, ending with 400-grit. (The larger the grit number, the finer the abrasive.)
Sometimes, the surface is smooth enough after grinding that it is ready for a penetrating sealer, and it’s then good to go. But often the concrete has air gaps, which can be filled with a slurry of cement, pigment and a liquid similar to white glue, or with epoxy. The filler might need a day to cure, and then the crew could lightly sand it and apply the sealer.
Some refinishing jobs are even more complicated. For example, if a countertop has an epoxy coating — which Seay said yours does not appear to have, based on the picture you sent — his crew would need to strip it off with chemicals, which would add a day’s work to the job.