For supported scaffolds, the poles, legs, posts, frames, and uprights must bear on base plates and mud sills or another adequate firm foundation 5, 11. The footings should be level, sound, rigid, and able to support the loaded scaffold without settling or displacement 5, 11. Unstable objects should not be used to support scaffolds or platform units 5, 11.

Additionally, a scaffold built from the ground or another surface should be supported by a foundation of sufficient area, stability, and strength to ensure the scaffold's stability [1]. It should be set level on a stable sill that is at least 38 x 240 millimeters and continuous under at least 2 consecutive supports [1], and have a base plate installed in any upright that could penetrate the sill [1].