A putlog is a horizontal tube which is used when there is only one row of standards. A putlog is fixed to the scaffold like a transom, but with one end supported by the building or structure against which the scaffold is being erected.

Transoms or putlogs should be laid no more than 1.2m apart if used for supporting 38mm scaffold boards. If using 50mm scaffold boards then they should be laid no more than 2.6m apart. The actual length of the of the transoms or putlogs is determined by the width of the working platform, this width is determined by the by the intended use of the scaffold. Working platforms should have a minimum width of 600mm.