The goal of any sealer is to protect the concrete. Concrete is porous, just like a sponge. The purpose of a sealer is to fill all of the holes in the concrete and to build up a thin shell that will protect the surface. There are three types of sealer available: penetrating, topical, and hybrid sealers. A hybrid sealer will soak into the concrete, similar to a penetrating sealer, and leave a micro-topical shell that helps provide some abrasion resistance. Additionally, a sealed countertop should be waxed to minimize friction and help protect the sealer.
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, and without some maintenance, it could start to feel like you're preparing food on the garage floor.
Sealers usually come in two finish types: satin and gloss. A glossy sealer will have a wet look, while a satin sealer will have a more natural look and feel. The glossy sealers have a tendency to look unnatural, and here at CHENG we try to maintain the natural qualities of the concrete. All of our work is sealed and protected, but it's all very subtle.
CHENG Sealer is 100% food safe and contains no harmful VOCs. It's easy to apply, and the tips in this Instructable will help you achieve a finish that looks great and protects the countertop for a long time. CHENG Sealer is a water-based acrylic, this means it is full of acrylic particles suspended in water. The acrylic particles are what fill in the holes, and this is what actually seals the concrete.
- Rubber Gloves
- (2) 1-gallon buckets (1 empty, 1 filled with water)
- Terry Cloth Towel
- CHENG Concrete Sealer
Step 1: Mix Sealer Dilution
- 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.
- 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 2: Saturate Project With Water
- Clean the concrete thoroughly with soapy 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 3: Saturate Project With Sealer
- 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 4: Wipe Up Excess 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 5: 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 buffed with #0000 steel wool to remove any streaks or to give the surface a matte finish.
Step 6: Wax
Waxing a countertop can be a lot of work, but it's an important step in the sealing process because it will reduce friction, helping to preserve the sealer from damage by pots, pans, and everyday use. CHENG Concrete Countertop Wax is a premium carnauba wax designed for concrete countertops, drying extremely hard to provide a protective coating.
How to apply CHENG Wax:
- Use a 100% cotton towel or an applicator pad that won't scratch.
- Apply by hand or with an orbital buffer.
- Dampen the pad with water, wring it out, and apply the wax.
- Wax small areas at a time with tight circular motions.
- The wax dries extremely hard and needs to be buffed off while still soft.
- Apply up to 3 coats on a new countertop.
- Re-wax every few months or more for high traffic areas.
If you ever notice the sealer wearing thin and water soaking in, that's an indication that it's time to re-seal your countertop. This is done by first removing the old sealer with a Concrete Sealer Remover, and then by repeating the steps in this Instructable.
A hybrid sealer makes spot cleanup easy because it's not necessary to strip the entire countertop like you would with other sealers. Only the affected area needs to be stripped, renewed, and re-sealed.