At REA JET, we provide marking and coding solutions for the wood industry, and thought readers may find it interesting to learn more about the letters/symbols often found on framing lumber. Because lumber is derived from trees, there is a chance that any piece of framing lumber may have a defect (such as a split or knot that can affect its strength). Sawmills have trained inspectors who give each piece of lumber a “grade” stamp, which tells contractors or others using the lumber much about its stiffness, strength, moisture content, and more.
Softwoods used in framing have certain words or letters that indicate the wood’s origin, and thereby its strength. For example, Douglas Fir is one of the strongest framing-grade softwood, the lumber containing letters including Doug Fir, D Fir-L. The types of lumber considered to be the weakest include Spruce, pine, or fir, which will be indicated by a stamp of S, P, or F depending which species it is. Southern pine is often used in framing, and is indicated by SYP.
When it comes to grade (best in visual appearance and strength), framing lumber is ranked from “Select Structural” (top grade, the highest ranking) to No.3, the lowest in terms of strength and a nice appearance. Lumber is graded and given a ranking of “Select Structural” to No.1, No.2, and No.3. Essentially, the higher the number, the lower the quality – and the cheaper the price. Any lumber graded as “stud” lumber is good for use in framing out exterior walls, or those walls considered load-bearing.
Moisture content is indicated by markings that include S-GRN (surface green), AD (air dried), KD (kiln dried), S-DRY (surface dry), or KD-HT (kiln dried and heat treated, a process used to kill pests in lumber that’s imported).
There are also certification and mill marks used to identify the agency that oversees grading accuracy, and provide the number or trademark of the mill where the lumber was produced.
Manufacturers of lumber or wood products can rely on REA JET for all of your wood marking needs. Our High Resolution Printer is exceptional for marking construction and profiled lumber, wooden boards, planed blued wood, and more. Reliable, legible printing even under the harshest conditions, you can count on REA JET for cost-effective solutions.