Question: An interesting situation has come up where some engineers are being told that the International Building Code (IBC) no longer allows horizontal diaphragms where sheathing panels are applied with the long axis parallel to framing as is the case with panelized roof assemblies.
The APA Publications Index, Form B300 NN, has been updated. The revised 2008 index provides a complete listing of APA design and construction guides, product guides, builder tips, case histories, industrial publications and other materials available from the Association.
APA just issued the 2007 Engineered Wood Construction Guide, the major reference manual for using engineered wood products in residential and commercial construction.
The standard APA panel diaphragm table contains a variety of diaphragm configurations that provide workable solutions for most designs. For some large commercial buildings, however, the maximum blocked diaphragm capacity of 820 plf can be a significant limitation. In the case when shear demand exceeds 820 plf, one can utilize the high load diaphragm table.
ICC ES Legacy Report ER-1952 mentions, “minimum spacing between lines [of nails] is 3/8 inch.”
The purpose of spacing a line of nails every 3/8 inch is to help minimize the potential of wood splitting. We’ve heard some inspectors are interpreting this 3/8 inch distance as the space needed between nail heads. We believe this interpretation is incorrect. The splitting of the framing caused by nails has very little to do with the size of the nail head, but is strongly influenced by the shank diameter of the nail.
