Chapter 7 of 124% of exam
Wood, Plastics & Composites
Wood (5 of 115 items) covers framing lumber and its dimensions. This chapter reviews nominal versus actual sizing.
Nominal versus actual lumber dimensions
Framing lumber is called out by nominal size, but the actual dressed dimension is smaller: a nominal 2x4 actually measures 1-1/2 inches by 3-1/2 inches after surfacing. Framers and estimators must use the actual dimensions for layout, stud spacing, header sizing, and material takeoffs. Engineered wood products (LVL, I-joists) are sized to their published structural values.