Grading Methods

Southern Pine

Lumber Grading Methods

Southern Pine lumber grading is more than just visually inspecting wood for knots. Training graders is a rigorous, time-consuming process, as they must consider many characteristics to assure the lumber meets American Lumber Standard Committee (ALSC) standards and buyers receive the proper grade. The task of grading requires training, supervision, experience, and control and auditing systems that take years to understand and master.

Simply put, do not assume you can simply read grade rules and apply them or grade lumber yourself.

With that said, there are three Southern Pine lumber grading methods for sorting dimension lumber and assigning design values:

Visually Graded Lumber

This is the oldest and most common of the three methods where qualified graders perform visual grading in the mill. These graders sort each piece of lumber into various grades based on visual characteristics known to affect lumber strength and stiffness, such as knot size and slope-of-grain.

Consistent visual grading is achieved through proper training, education, and supervision of lumber graders. Visually graded lumber will adequately meet the structural requirements for most traditional applications.

Machine Graded

Grade marks for Machine Stress Rated (MSR) lumber and Machine Evaluated Lumber (MEL can include “1W” or “2W” if visually graded to the wane restrictions for No. 1 or No.2 visual grades, respectively. While each machine grading technique reduces the variability associated with assigning stress grades to lumber, there are slight differences between the two:


The Standard Grading Rules for Southern Pine Lumber provide for numerous visual, MSR, and MEL grades. However, not all of those possible grade/size combinations are produced or used in the marketplace.

Available grades and sizes are subject to change, so check your supply sources at the time of your project.