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Base Section
It is impossible for a stable structure to be built upon a foundation that does not start out square and level. OSHA has standards that apply specifically to the steps that must be taken to assure a stable scaffold base. Note: Except where indicated, these requirements also apply to manually propelled, pump jack, ladder jack, tube and coupler, and pole scaffolds, as well as the specialty scaffolds described in the Supported Scaffolds module.
Firm Foundation
  • In order to assure stability, supported scaffolds must be set on:
  • Footings must be capable of supporting the loaded scaffold without settling or displacement. [1926.451(c)(2)(i)]

  • Unstable objects may not be used to support scaffolds or platform units (Figure 1). [1926.451(c)(2)(ii)]

  • Front-end loaders and similar pieces of equipment shall not be used to support scaffold platforms unless they have been specifically designed by the manufacturer for such use. [1926.451(c)(2)(iv)]

  • Forklifts shall not be used to support scaffold platforms unless:

    • the entire platform is attached to the fork, and

    • the forklift is not moved horizontally while the platform is occupied. [1926.451(c)(2)(v)]

Tip: One way to ensure a stable foundation, when a sill is used, is to secure it to the baseplate (Figure 2).

Figure 1. Poor foundation: Scaffold end frames, which have no base plates, erected on top of scrap wood and unstable cement blocks. [1926.451(c)(2)(ii)]

Figure 1.
Poor foundation: Scaffold end frames, which have no base plates, erected on top of scrap wood and unstable cement blocks. [1926.451(c)(2)(ii)].


Figure 2. Proper foundation on wood sills: Scaffold end frames equipped with adjustable screw legs and with base plates set on mud (wood) sills.

Figure 2.
Proper foundation on wood sills: Scaffold end frames equipped with adjustable screw legs and with base plates set on mud (wood) sills.



Plumb
  • Supported scaffold poles, frames, uprights, etc. must be plumb and braced to prevent swaying and displacement. In general, a level is the easiest way to achieve the desired right angles. [1926.451(c)(3)]

Figure 3. Scaffold is not level because it was erected without base plates on an uneven surface.

Figure 3.
Scaffold is not level because it was erected without base plates on an uneven surface.

 
 
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