ABSTRACT
Specifiers and grading agencies compensate for sawn lumber's heterogeneity and unique organic characteristics by categorizing it by size, species, and grade. Hence, specifying a 2x4 tells a structural designer little about the member. To be complete, a structural designer must note the size, species, and grade of a member, for example, a Douglas-Fir, Select Structural, 2x4. Many lumber yards are not so precise in defining species and grade in the yard or on the bill. However, someone at the lumber yard will know exactly what they are selling; it is the structural designer's responsibility to find out the species and grade of the lumber they are purchasing.
