There are three methods of installing plank decking.

The first method, called controlled random, is the most economical because random length material is used. The controlled random pattern is shown in the figure below and consists of the following:

  • Each deck must consist of at least 3 spans.
  • End joints are not permitted in the outer half of end spans.
  • End joints in adjacent courses must be staggered at least 600mm (2′).
  • Where end joints occur in the same general line, they must be separated by at least two intervening courses.
  • In floors and roofs, planks which do not span more than one support must be flanked by courses resting on both supports of that span. They must be separated from the next unsupported plank by at least six courses extending over at least one support (this is only permitted for double tongue and groove planks at least 64mm (2-1/2″) thick).



The second method is called Simple Span. All pieces rest on two supports and are the same length. The third method is Two Span Continuous. All pieces rest on three supports and are the same length. Both the latter methods require planks of predetermined length and a consequent cost premium.