Understanding lumber grades will help ensure you meet design expectations. Lumber grades are divided into three basic categories: structural framing products, appearance products and industrial products.

Structural framing products are graded for their strength and other physical properties, as opposed to appearance products, which are graded for their aesthetic properties. Industrial products include a combination of both structural and non-structural properties.

The American Lumber Standard Committee lumber program, operating under the Board of Review, currently has 31 accredited independent third-party agencies headquartered throughout the United States and Canada. Each of these agencies operates under one or more of the seven sets of grading rules certified by the Board of Review as conforming to the American Softwood Lumber Standard PS 20.

Learn more about structural lumber grades with these resources.

Douglas Fir

Western Wood Products Association:

Grading

Products Graded for Structural Applications

Moisture Content & Seasoning

Eastern White Pine

Northeastern Lumber Manufacturers Association: Standard Grading Rules for Northeastern Lumber

Hem Fir

Western Wood Products Association:

Grading

Characteristics & Best Uses

Framing Products

Ponderosa Pine

Western Wood Products Association:

Grading

Characteristics

Southern Pine

Southern Pine Inspection Bureau:

Southern Pine eLearning Course

Lumber Grading Rules

Southern Forest Products Association: Southern Pine Grade Descriptions

Spruce-Pine-Fir

Species & Characteristics

Design Values

West Coast Lumber Inspection Bureau

Grading Rule PDFs by Section

Interpretations for the National Grading Rules for Dimension Lumber 

WCLIB Standard No. 17 Grading Rules for West Coast Lumber 2004 

Western Wood Products Association

Grade Categories: Structural

Structural Framing Products

Interpreting the Grade Stamp

Specifying Framing Grades

Supplement No. 1 – Western Lumber Grading Rules 2017