How to Paint Concrete to Look Like Granite

Clean the concrete surface thoroughly with water and a concrete degreaser, following the manufacturer's instructions carefully. Scrape away solid particulate with a putty knife and scrub stubborn stains with a stiff broom.

Sand the surface of the concrete with a floor-buffing machine, using 80-grit sandpaper strips. This helps open the pores of the concrete so it will readily accept the paint. Sweep away excess dust, then wash the surface using the floor buffer equipped with strip pads. Remove any remaining suds with a wet-and-dry vacuum.

Apply a layer of concrete primer to the surface using a high-quality 1/2-inch-nap paint roller. Concrete is a very porous material, which makes it difficult for some paints to adhere to it properly. Concrete primer fills the pores so the paint can remain on the surface, where it looks best. Allow the concrete primer to dry for at least eight hours before applying the first coat of paint.

Select the colors of your faux granite in latex paint. You need a base coat and three complementary colors. The three colors should vary in darkness.

Paint on a coat of your base color using a high-quality paint roller. If the base coat is very thin, you may want to apply two layers, allowing it to dry in between applications. The base coat will have several other colors on top of it, so it needs to be readily visible before you begin covering it up. Allow the base coat to dry completely.

Sponge on the mid-range color of your paint, covering the concrete surface uniformly. Turn the sponge at random to achieve different patterns. The more variation you use when sponging the paint on, the more unique your faux granite will look. Clean the sponge thoroughly and allow the paint to dry for about two hours before continuing.

Apply the darkest of your three colors in the same manner with the sponge. Cover less of the surface with the darkest color than you did with the mid-range color. For the best results, you should still be able to see a good bit of the mid-range and base colors through the layer of the darkest color. Wash the paint out of the sponge and wait two hours before moving to the next step.

Add a layer of the lightest color that you chose. Sponge the paint on in the same manner, turning the sponge randomly to vary the pattern. This lightest color should be your dominant color, so apply it to most of the surface, leaving patches of the other colors showing through. Clean the sponge thoroughly and allow the paint to dry for two hours.

Combine four parts of latex glaze with one part of paint, chosen from the colors used in the faux granite process. Sponge this mixed glaze onto the concrete very sparsely, pressing very gently. This gives the concrete a slight shimmer. Allow the glaze to dry for two hours before proceeding.

Apply a coat of water-based clear coat to the concrete surface using a high-quality paint roller. This gives the faux granite a realistic polish and high-gloss finish, as well as provides a protective coating for your surface. Allow the gloss to dry for four to six hours before walking on it, and 24 hours before replacing furniture or heavy items.