Precast Concrete Countertops


Sealing is especially important for a kitchen countertop. Acidic foods like vinegar, wine, mustard, etc. will etch the surface of the concrete and many other things will stain unsealed concrete. Even everyday wear and tear, like dragging pots and pans across the surface, will take its toll on the concrete.

Follow these step-by-step instructions and learn how to seal a concrete countertop using CHENG Hybrid Concrete Countertop Sealer.

Video – How to Seal Concrete Countertops

Step 1 – The Right Environment

  • Always indoors or in the shade when possible.
  • Away from moving air.
  • In a dust-free location.
  • Avoid anything that will cause the sealer to dry too quickly. If the sealer dries too quickly, this can cause streaking when it’s being wiped off.

Step 2 – Dilution

  • 30% sealer : 70% water
  • 100% sealer is difficult to work with, so we apply a lot of thin coats.
  • The amount of sealer you need will depend on the size of your project. CHENG Sealer comes in two sizes, 4 Liter (200-400 square feet coverage) and 500 mL (30-50 square feet coverage).

Step 3 – Soak With Water

  • Rinse the concrete thoroughly with clean water, using a 100% cotton cloth that won’t scratch the surface.
  • If the concrete you want to seal has been sealed and waxed before, remove the wax with mineral spirits.
  • Use a fresh rag and wipe down the surface and edges of the countertop with water until the whole countertop darkens.

Step 4 – Apply Sealer

  • Sealer is best applied with a lot of thin coats, like spray-painting. It is difficult to work with a 100% sealer concentration. Diluting it with tap water will make it easier to apply with less chance of the sealer streaking as it dries.

    •    Soak the rag in the sealer dilution (30% sealer to 70% water) and wipe down the countertop, starting with the edges.
    •    Liberally apply sealer to the whole piece, and agitate it with the rag for about 5 minutes.
    •    Let the sealer soak into the concrete, applying it uniformly and methodically, making sure you don’t miss a section. If the piece is big, work quickly before the sealer starts to gel. At that point, you’ll be smearing the sealer and causing streaks.

Step 5 – Wipe Up Sealer

  • Wipe up the sealer with the same rag, and wring it out back into the bucket of sealer dilution.
  • The idea here is to leave a very thin and uniform layer of sealer on the surface, not to dry the countertop completely.
  • Avoid streaking by working quickly and methodically and in a shady, cool place.
  • For “new” concrete, you’ll apply sealer like this anywhere from 3 to 6+ times until the concrete doesn’t darken anymore when water is dripped on the surface.

Step 6 – Water Drop Test

  • After the concrete has been sealed and allowed to dry overnight, you can perform a water-drop test to check the sealer.
  • Pour water on the countertop and let it sit 10 minutes.
  • Soak up the water, and if the surface has darkened, it isn’t fully sealed. Repeat Steps 2-4 until it passes the water-drop test and the surface doesn’t darken.
  • When the countertop is fully sealed, the sealer can be burnished with diamond infused hurricane pads to remove any streaks or to adjust the surface sheen.
Previous: Polishing

Wet-polish with coarse diamond polishing pads that expose aggregate by cutting deep into the concrete, or use a finer pad for a more uniform finish.

Next: Waxing

Waxing a concrete countertop protects the sealer from the wear and abrasion of daily use. Pots and pans can take a toll, so wax regularly.