Lumber quality is designated by grades that are assigned at the mill during the manufacturing process. Certified graders look at each piece of lumber and assign a grade based on the criteria they have learned and are certified to assign. New technology is available that enables computer managed scanner to assign grades. Typical lumber grades are as follows:
Select Structural: This is the highest grade of framing lumber. Select Struc will have the least amount of imperfections, The knots will be small, tight and well spaced throughout the board.
1&Btr: Similar to Select Struc, a few more imperfections are allowed.
2&Btr: Most common grade of lumber, typically used for home framing. Imperfections are allowed. Knot’s of any condition are acceptable as long as they are well spaced.
2&Btr Premium:Same as above, but also graded for appearance. Typically will have 4 square edges.
Standard & Btr: Similar to 2&btr but only used in narrows (2×4, 2×6)
Stud Grade: Specifically graded for vertical/downward strength. There are varying levels of appearance within the grade.
MSR: Machine Stress Rated lumber- is stress rated at the mill to varying PSI (pound per square inch). This type of lumber is typically used in truss manufacturing.
Utility: Utility grade lumber is the lowest grade. Suitable for light framing and temporary bracing.