Plywood Diaphragms

[8911]

In diaphragm calculations what figure does one use for the depth of the diaphragm? the upper chord length from eave to peak? or the length from eave to eave over the peak? Say in a roof with a 5:12 pitch

 

[seattlemike]

I recommend using the exterior-wall-to-exterior-wall distance: the distance between your chords.

Check Donald Breyer's Wood Design book for additional information.