Grading Rules

Mill workers learn about grading rules at an AFPA lumber grading course.

Lumber is graded to strict standards to ensure consistency and structural integrity. Grading rules are developed by the National Lumber Grades Authority using the latest research methods including strength testing machines.

The standards specify characteristics including maximum allowable splits and checks (cracks). You can see the rules for different grades using the lumber grading charts.

Click below to check out our first Lumber Grading 101 Video!