Copyright Goodheart-Willcox Co., Inc. Chapter 3 Tools and Equipment 41 3.3 Concrete Masonry Tools and Equipment Most tools used in concrete masonry are designed for use in finishing horizontal concrete surfaces. These tools are known as flatwork finishing tools. 3.3.1 Screeds A screed is a straightedge or strike-off rod made of any straight piece of wood or metal that has sufficient rigid- ity (stiffness). It is the first finishing tool used by a cement mason after the concrete is placed. A screed is used to strike off the concrete surface to the proper level. Screeds come in many sizes and materials based on the application and size of the job. Most common metal screeds are made of either aluminum alloy or magne- sium alloy. They vary in size from 1″ × 4″ to 2″ × 5″ with lengths varying from 6′ to 24′, depending on the width of the concrete project being constructed. Aluminum and magnesium metal screeds will not rust or rot, and are warp-resistant. Metal screeds are lighter because they are hollow. Figure 3‑38 shows screeds with end- caps to keep concrete from entering the screed. A power screed, shown in Figure 3‑39, is used for most concrete work because it saves time. Through the vibration that it creates, the screed drives the surface rock into the mixture and brings a layer of liquid con- crete, sometimes called “cream,” to the surface of the concrete mixture. Safety Note When using metal equipment, such as a screed or bull float handle, it is important to keep the tool away from overhead electrical wires. Severe harm or death may occur if the tool comes in contact with overhead energized wires. 3.3.2 Tampers Concrete hand tampers are used to compact concrete into a dense mass. These tools are used on flatwork construction with low-slump concrete, which is usu- ally stiff and hard to work. A tamper also pushes large aggregate below the surface so it is not exposed, result- ing in a smooth finish. See Figure 3‑40. Marshalltown Company Figure 3‑38. Magnesium screeds come in different lengths, widths and thicknesses depending on the application and the size of the project. Marshalltown Company Figure 3‑39. A power screed is used to remove excess concrete and to vibrate the surface of freshly placed material. When screeding, the blade rides on top of the forms to level the concrete. Marshalltown Company Figure 3‑40. A hand tamper aids in driving aggregate down into the concrete to bring the liquid concrete to the surface.