structural lumber

structural lumber

Lumber consisting of the following classifications: 1.Beams and stringers : Lumber of rectangular cross section, 5 in. or more thick and 8 in. or more wide; graded with respect to its strength in bending when loaded on the narrow face. 2.Joists and planks : Lumber of rectangular cross section, 2 in. to (but not including) 5 in. thick, and 4 in. or more wide; graded with respect to its strength in bending when loaded either on the narrow face as a joist or on the wide face as a plank. 3.Posts and timbers: Lumber of square or approximately square cross section 5 in. by 5 in. and larger; graded primarily for use as posts or columns carrying longitudinal load but adapted for miscellaneous uses in which strength in bending is not especially important.