Double and cantilever scaffolding

Double scaffolding

This is also called a mason's scaffold. Two rows of standards are put up, the first close to the wall (about 20-30 cm) and the second at 1.2-1.5 m from it. Ledgers join the standards, putlogs rest on both rows of ledgers (not in the wall), and braces make the frame rigid. It is used for stone masonry and heavy work where holes in the wall are not allowed.

  wall |std  ledger  std
  wall |  |=putlog====|
  wall |  |  boards   |
  wall |  | /brace    |
  wall |__|/__________|__ sole plate

Use: stone masonry, tall buildings, heavy work.

Cantilever scaffolding

Cantilever scaffolding is a scaffold in which the platform is carried on needles (projecting beams) that cantilever out from the wall, instead of on standards resting on the ground. It is used when the ground cannot support standards (e.g. beside a basement, or on soft or sloping ground), or when the building is on a street where the pavement must remain free.

Parts: needles (steel/timber beams), struts or braces, standards on the needles, ledgers, putlogs, boards and guard rails.

Types:

1. Needle (built-up) type: needles pass through holes in the wall and are anchored inside by a counterweight or by tying to the floor.
2. Truss-out type: needles are supported by inclined struts fixed to the wall.

              guard rail |
    wall |== boards ======|
    wall |==== needle ====|
    wall |           /
    wall |         /
    wall |       /  strut
    wall |     /
    wall |   /
    wall | /

Use: where the ground cannot support standards, or in busy streets.