Structural Lumber Buyer Best Practices

Component manufacturers (CMs) do not simply purchase lumber for use in their products, but rather, they purchase and rely on the design values attributed to that lumber. In North America design values are determined and verified by six grading agencies certified by the American Lumber Standards Committee (ALSC), operating under the U.S. Department of Commerce Voluntary Product Standard for lumber, PS 20.  

PS 20 requires that every piece of structurally graded lumber be marked with a grade stamp containing five pieces of information: species or species group, grading agency trademark, mill identification, grade, and moisture content. The grade stamp serves as both an effective method for tracing each piece of lumber back to the mill it was manufactured at, as well as an immediate reference to the lumber’s published design values. 

For CMs and others who use structurally graded lumber, there are a few best practices to follow to ensure the lumber you receive matches your expectation at the time of purchase. 

1. Specify specific species/species groups and grades at the point of purchase. Whether the buyer contacts the mill directly, or works through a broker, wholesaler, or buying co-op, the buyer should be very clear in their requirement for specific grades and species/species groups. Species groups in the U.S. and Canada may have similar names, such as SPF and SPF(S), or DF-L and DF-L(N), but because they are grown in different regions they have different published design values. Don’t assume the seller fully understands the difference in design values.
2. Inspect all lumber bunks upon delivery. Transporting lumber from the manufacturing mill to its end destination is not always quick or straightforward. While most lumber bunks are wrapped in poly before they leave the mill, this does not mean the lumber is fully protected from the elements. Further, damage may occur during the loading, transport, and unloading process. Random pieces from each lumber bunk should be visually inspected to verify the correct species and grade on the grade stamp. Finally, it is a good practice to test the moisture content of the lumber to ensure it isn’t significantly different than what is marked on the grade stamp.
3. Clearly communicate lumber quality issues with the seller. Your customers never hesitate to inform you when there is an issue with your product in the field. Hold your lumber seller to the same standard. Communicate clearly and often when the lumber product you purchase does not meet your expectations with regard to species, grades, moisture content, or lumber quality issues like wane, check, bow, etc.  

Incorrect species, grades, moisture content, and/or quality can have a significant impact on the efficiency of a CMs production process. More importantly, they can affect the long-term performance of a CM’s products. Following these lumber purchasing best practices can help reduce headaches in the manufacture, installation, and performance of structural building components.