Ponderosa Pine
Pinus ponderosa

Grading & Quality Control

Grading

Timber grading rules assure consistent standards of quality, regardless of which mill produces the timber. In the 12 Western states, the primary growth area for Ponderosa Pine, the largest percentage of pine production is graded under the supervision of Certified Inspectors from the Western Wood Products Association (WWPA), a grading and quality control agency accredited by the American Lumber Standard Committee, Inc., under the U.S. Department of Commerce. The most widely produced grades are SELECTS, COMMONS and Factory & Shop products intended for remanufacturing. Special grades are available through buyer/seller agreements.

Appearance Grades

Ponderosa Pine products are graded primarily on appearance for a multitude of applications. Under the WWPA Western Lumber Grading Rules, there are three grades of SELECTS (for clear and nearly clear products) and five grades of COMMONS (for general-purpose products where a variety of knots and other characteristics are allowed). Many WWPA Member mills also produce products according rules published by the West Coast Lumber Inspection Bureau (WCLIB). These Standard Grading Rules provide for five grades under the BOARD rules, each with specific limitations on the number, size and type of knots as well as other characteristics.

Structural Grades

Ponderosa Pine structural grades are used where light to moderate strength levels are required. The 2X4 and 2X6 sizes are especially popular as a decking material, once the timber has been pressure treated with preservatives for outdoor in-ground or above-ground applications.

Factory & Shop Grades

Factory & Shop grade timber products are intended specifically for remanufacturing into furniture, doors, windows and shutters. Such wood is selected to be almost completely free from pitch and resin pockets, has an even grain, and is dimensionally stable. The grades have evolved on the basis of millwork cutting sizes and are defined in the grading rules by the number of clear, standard-size cuttings that can be obtained by ripping and cross cutting the various products. These grades are often referred to the “economical clears” of the timber industry. They are used throughout the world for an endless array of products that require various sized pieces of clear wood. 

COURTESY OF MARVIN MANUFACTURING CO.

© 2001 WWPA/SEC