Reinforcing bar assemblies, known as standees, are normally required for support of top mats of reinforcing bars in thick concrete members, such as footings and slabs. Standees are readily available as a standardized product up to 18 in. (457 mm) in height, but various sizes and configurations of standees have also been used in thick mat footings. Four common types of standees are illustrated. Safety is of paramount importance when designing a bar support system for heavy top mats of reinforcing bars. Standee spacing must be carefully determined to support the dead loads, and bracing must be adequate to handle all lateral forces.