A grade mark is the most common way of identifying important structural properties and quality of sawn lumber in accordance with US DOC PS 20 American Lumber Standard.

Occasionally, state legislation is proposed that would create an exception to grading and grade marking of sawn lumber, allowing the use of locally-sourced, sawn lumber in residential construction or an associated accessory structure. The law seldom goes into detail on how the lumber grade is to be assigned or how to ensure that the material is locally-sourced, leaving it to the building official to deal with the challenges of permitting use of unmarked lumber of potentially unknown origin to meet intent of the code in terms of quality and safety. 

Often, the laws are unnecessary, since the International Residential Code (IRC) has provisions for use of sawn lumber that has no grade mark. Section R502.1.1 of the 2021 IRC allows the use of a certificate of inspection issued by a recognized lumber grading or inspection agency in lieu of a grade mark:

“R502.1.1 Sawn lumber. Sawn lumber shall be identified by a grade mark of an accredited lumber grading or inspection agency and have design values certified by an accreditation body that complies with DOC PS 20. In lieu of a grade mark, a certificate of inspection issued by a lumber grading or inspection agency meeting the requirements of this section shall be accepted.”

Identification of sawn lumber conformance to requirements of US DOC PS 20 American Lumber Standard, either by grade mark on each individual piece or through a certificate of inspection, is fundamental to safe use in accordance with the code. Without knowing the grade of sawn lumber, the IRC prescriptive designs, including the span tables based on structural properties of graded sawn lumber, cannot be used and engineered designs cannot be performed due to lack of design values.

The American Lumber Standards Committee (www.alsc.org) has contact information of recognized lumber grading and inspection agencies throughout the country. These agencies can help identify local grading services that are able to issue a certificate of inspection for sawn lumber that is not grade marked.