Upgrade a plain cement slab or walkway with a flagstone-style finish using paint and homemade stone stamps. Upholstery foam or thick shipping foam cut into somewhat random flagstone-sized shapes serves as the stamp material. Mix and match several paint colors to recreate the natural shade variations found in a real flagstone floor or pathway.
Before painting the cement, clean it thoroughly to remove grease, grime and gunk the material has absorbed over the years. Use a special cement and concrete degreasing product and a long-handled scrub brush to get into all the nooks, cracks and crevices in the cement. If the flooring or walkway is made from a smooth troweled concrete, it must be etched as well or the paint won't stick. Use an all-in-one cement degreaser and etcher to save time. Rinse the area thoroughly afterward and allow it to dry for at least 24 hours before painting.
Cover the corners of adjacent structures such as porch posts or a garage wall with painter's tape to protect surfaces that should not be painted.
Pour the base-color shade of the latex floor and patio enamel into a paint tray after stirring it with a stir stick. If unsure which shade to use for the base coat, select a light gray or tan tone that will also serve as the grout color.
Dip a paint roller into the paint, rolling the excess off into the shallow area of the paint tray. Paint the entire cement area with the base color and allow it to dry for at least 24 hours.
Tear four or five pieces of upholstery foam or snap hunks of shipping foam into relatively straight, slightly jagged flagstone shapes by hand. If it is difficult to start the tearing or breaking process, score a rough line on one side of the foam with a utility knife, then tear or snap the foam along the line. Each piece should be between 2 and 10 inches wide and as long as you'd like, depending upon the size of the project area. The pieces should be different from one another to add variety.
Place a plastic tarp next to the project area.
Open and stir the remaining paint colors. Pour a pool of each color onto the tarp so the pools touch one another. Swirl the paints just a little with a stir stick.
Dip a flat side of one of the foam flagstone stamps into one of the paint shades, picking up a bit of one of the other colors. Line the stamp up along an edge of the project area, then press the stamp down onto the cement.
Dip a different foam stamp into the paint, wiggling it back and forth gently through the paint colors. Stamp it along the cement next to the first stamped area, leaving 1/2 inch or so of the base coat showing so it resembles grout. Continue dipping and stamping the cement, working your way along the project area stone by stone, as you would if laying out actual flagstone pieces.
Allow the paint to cure for 24 hours or longer before setting furniture atop it. Check the paint container for manufacturer's recommended curing times.