How to Marbleize and Seal a Basement Concrete Floor

Sweep up all dust and debris. Mix a solution of TSP and water, then mop the concrete, scrubbing to remove all stains, grease spots and ground-in dirt. Rinse with clean water and wipe up with old rags. Allow to dry completely.

Mask around the baseboards with 3-inch-wide painter's tape.

Apply two thin coats of concrete primer, using the 3/8-inch roller on a pole. Allow to dry between coats according to the manufacturer's directions.

Paint the entire floor with the base coat, which is the primary color in your faux marble floor. For example, if you've chosen a carrara marble finish, paint the entire floor with an eggshell finish, off-white latex paint. Allow the floor to dry overnight or at least eight hours.

Tape a small paintbrush or foam brush to a bamboo pole. This allows you to stand while painting the marble veins onto the floor.

Mix equal parts of raw umber and dark brown acrylic paint. Moisten the tip of the paintbrush in water, then draw it through the paint mixture. Begin in one corner of the room and draw long, irregular lines diagonally onto the floor. Roll the brush as you work so the lines are randomly thinner and wider.

Add crisscrossing thin lines across the larger veins until the floor is covered with gray-black lines.

Remove the small brush from the pole and replace with a 2-inch-wide paintbrush. Mix equal parts of glaze and yellow umber. Quickly brush streaks of the thinned paint across the veins. If the color seems too dark, add more glaze.

Brush a 4-inch-wide dry brush across the moist paint. Lightly brush the golden streaks in the same direction as the original diagonal pattern of veins.

Mix a glaze of 1 part white paint and 3 parts clear glaze. Dip a sponge mop into the white glaze and wipe across the entire floor, again in the direction of the diagonal veining. Use a rag to blot and remove excess glaze or add more glaze as needed. Once the finish is satisfactory, allow to dry completely according to the manufacturer's directions.

Apply four to six coats of satin-finish polyurethane sealer for floors. Allow the polyurethane to dry between coats according to the manufacturer's directions or at least eight hours.