Dressed vs Rough Sawn
nominal (stated) size vs dressed (actual) size
subtract 1/4" if < 2"
subtract 1/2" if 2"-6"
subtract 3/4" if >6"
Nominal Dressed 1" x 2" 3/4" x 1-1/2" 1" x 3" 3/4" x 2-1/2" 1" x 4" 3/4" x 3-1/2" 1" x 5" 3/4" x 4-1/2" 1" x 6" 3/4" x 5-1/2" 1" x 7" 3/4" x 6-1/4" 1" x 8" 3/4" x 7-1/4" 1" x 10" 3/4" x 9-1/4" 1" x 12" 3/4" x 11-1/4" 1-1/4" x 4" 1" x 3-1/2" 1-1/4" x 6" 1" x 5-1/2" 1-1/4" x 8" 1" x 7-1/4" 1-1/4" x 10" 1" x 9-1/4" 1-1/4" x 12" 1" x 11-1/4"
Nominal Dressed 1-1/2" x 4" 1-1/4" x 3-1/2" 1-1/2" x 6" 1-1/4" x 5-1/2" 1-1/2" x 8" 1-1/4" x 7-1/4" 1-1/2" x 10" 1-1/4" x 9-1/4" 1-1/2" x 12" 1-1/4" x 11-1/4" 2" x 4" 1-1/2" x 3-1/2" 2" x 6" 1-1/2" x 5-1/2" 2" x 8" 1-1/2" x 7-1/4" 2" x 10" 1-1/2" x 9-1/4" 2" x 12" 1-1/2" x 11-1/4" 3" x 6" 2-1/2" x 5-1/2" 4" x 4" 3-1/2" x 3-1/2" 4" x 6" 3-1/2" x 5-1/2" NDS Supplement table 1A & 1B
surfaced
RGH rough S1S surfaced one side S2S surfaced two sides S4S surfaced four sides S1S1E surfaced one side, one edge S1S2E surfaced one side, two edges rough sawn (approx. 1/8" larger) and full sawn (stated = actual size) are not in NDS
Width & Thickness of lumber vs Width & Depth of beam
beam - load applied to narrow face
decking - load applied to wide face