Copyright Goodheart-Willcox Co., Inc. 394 Section 5 Concrete Geometric Patterns A variety of geometric patterns can be stamped, sawed, or scored into a concrete surface to enhance the beauty of walks, drives, or patios. See Figure 18-30. Random flagstone or ashlar patterns are popular. They may be produced using a piece of 1/2″ or 3/4″ copper pipe bent into a flat S-shape to score the surface. Scoring must be done before the concrete becomes too hard to push the coarse aggregate aside. The best time is just after darbying or bull floating. After hand floating, a second scoring is required to smooth the joints. Patterns such as stone, brick, or tile can be cut into partially set concrete with special stamping tools, Figure 18-31. Color can also be added to create varying effects. See Figure 18-32. Other patterns can be created using divider strips of wood, plastic, metal, or masonry units. These divider strips help to create interest. They also aid in the placement of concrete, provide for combinations of various surface finishes, and greatly reduce random cracking. Wood divider strips should be made from pressure-treated lumber, redwood, or cypress. Stamping of concrete usually begins after screeding and finishing have been completed. The following procedure provides the general steps for stamping concrete. Consult the stamping equip- ment manufacturer’s specifications for detailed instructions. PROCEDURE Stamping Concrete 1. Apply color hardener on the concrete surface, fol- lowing the manufacturer’s procedures for coloring. 2. Apply the release agent on the concrete surface, following the manufacturer’s specifications. 3. Check the surface to determine if the concrete is ready for stamping. 4. Begin stamping in a corner, then work around the perimeter of the slab. The starting point is usually where the concrete was first placed in the forms. 5. Once the perimeter is completed, go back to the corner to begin the first row of stamping. Bomanite Corporation Figure 18-30. These colored concrete slabs have been scored to give the appearance of terra cotta tile. Stanley Goldblatt Figure 18-31. An imprint roller is creating a simulated stone pattern in concrete. Keith Muratori/Shutterstock.com Figure 18-32. A stamped concrete pool patio.