The foundation is the supporting structure on which a scaffold is erected. To ensure scaffold stability, the scaffolder must first ensure a sound foundation. Scaffold foundations must be adequate to carry and distribute the loads imposed at each standard and of the whole loaded scaffold. An inadequate foundation can cause a scaffold to collapse.
To ensure an adequate foundation, consideration should be given to the intended use of the scaffold and the environment in which it is to be erected.
To work out whether the supporting surface or foundation is adequate, consideration should be given to the load the foundation will be required to bear.
The purpose of a good foundation is to spread the leg load over a wide area. Consideration should be given to the ground or structure on which the scaffold is to be erected as well as the live and dead loads to be carried. The use of baseplates and soleplates are necessary to stabilise scaffolds and their foundations.
A sole plate is a member used to distribute the load through a base plate to the ground or other supporting structure. A base plate is a plate that is able to distribute the load from a load bearing member to a supporting structure. The foundation conditions will determine the requirement for base plates and soleplates and the dimensions and specifications of each.
The total load and the conditions of the supporting soil or floor determine the size of the foundation. When soil conditions are poor or frozen, it may be necessary to dig down to an adequate base material. If this is not practical, then the leg load must be spread over a much larger area using larger soleplates or continuous decking under the scaffold legs. To support scaffolds, backfilled soils must be well compacted and leveled. Mud or soft soil must be replaced with gravel or crushed stone that has been well compacted.