Fig. 143
Platform boards to be safe from tilting, should not project more than 6 inches beyond the putlogs. At this distance the weight of the workman is most over the putlog, and even if he stood on the extreme edge, experiments have shown that his weight is more than counterbalanced by the weight and length of an ordinary board.
Where scaffold boards are used as a means of communication between one part of the scaffold and another they should be laid in pairs, so as to form ‘runs’ at least 18 inches wide. To prevent unequal sagging they should be strapped on the under side. It would be better to have properly constructed gangways and most decidedly safer.
‘Bridging runs’ for barrows are usually three boards wide. Five boards wide is better, and, as previously shown, they should be joined to prevent unequal sagging.
Centering should be carried on supports which rise from a solid foundation ([fig. 143]). The practice of trusting the supports to keep their position under pressure from the stay A ([fig. 144]), or by being spiked to the new work, is to be regretted, as the only reason for its use is to effect a very slight saving of timber.
Fig. 144
Fig. 145