In article , Phil
Addison wrote:
Does that mean if you have 7x2 joists the struts/herringbones are
only needed on pairs of joists 42" apart. i.e. the intermediate
joists do not need strutts? I hope so as only some of my first
floor ones are strutted.

No the spacing is along the length of the joist, but ...

by the code the depth/breadth ratio is 3.5 so the only requirement
is for the ends of the joist to be held in position and the members
held in line "by tie rods or binders". For floors the strutting
requirement effectively only comes in for D/B5 - so if you had
8x1.5" joists they would need rows of strutting every 48"

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