How to Make Multiple-Colored Concrete Countertops

Add 3/4-inch plywood cut to fit with a circular saw over the base cabinets to provide support. Attach the plywood with screws driven into the cabinet walls.

Cover the plywood base with 1/4-inch cement backer board. Attach the backer board with screws.

Add concrete edge molding around the perimeter of the countertop area. Different edge molds are available to give a variety of finished profiles. Secure the edge molding with screws.

Cut two pieces of glass fiber reinforcement screen to fit into the countertop mold. Place one of the pieces into the form. Smooth it out flat on the bottom of the mold. Set the other screen aside.

Pour the concrete countertop mix into a bucket or mixing container. Stir the integral coloring agent you chose into the dry mix until it’s a uniform color. Add water according to package directions, and stir it with a mixing paddle attached to a drill for at least 10 minutes. Do not stir at a high speed, or the concrete may have bubbles that are hard to work out.

Add concrete to the form to within 1/4 inch of the top edge. Use a trowel to work the concrete into all corners and along the edge. Work out as many air bubbles as possible.

Set the second piece of reinforcement screen on top of the concrete in the form. Lightly press it into the concrete.

Finish filling the form with concrete, and smooth it with a float. Scatter colored stones or tumbled glass aggregate across the concrete top to add more color to the countertop. Press these items into the concrete so they are below the surface.

Remove the forms at the end of the 15-day waiting period.

Polish the countertop beginning with a 100-grit pad attached to a sander. After each pass, change the pad to a higher grit, finishing the project with a 3000-grit pad. Wipe off any dust that remains.

Apply a coat of concrete sealer to the polished countertop with a soft cloth. Wipe the excess sealer off after it sets for an hour. Apply two additional coats of sealer in a similar manner.