The changes to Clause 4 of the Standard reflect changes adopted in the 2005 NBCC, including the companion load action approach, the separation of live load and snow load, and the rationalization of importance factors for building types and loads. Clause 4 also provides minimum load criteria for calculating deflection in wood members.

Other revisions in the Supplement include increased specified shear values for sawn lumber; revised negative bending moment design values for glued-laminated timber; revisions to design values for structural sheathing OSB; and revisions to the clauses dealing with proprietary structural wood products. Additional information on compression perpendicular to grain capacity has been added in an appendix.