Timber Products Inspection, Inc.
Timber Products Inspection, Inc.
The demand for wood products in construction and the need for
wise use of our renewable resource - wood, call for effective use
of the entire tree. To make structural finger jointed lumber,
short sections of lumber are bonded into long, strong lumber
needed for construction using code approved finger joints.
Structural finger jointed lumber means more lumber from each log.
The same agencies that assure the quality of unjointed lumber oversee the production of Structural Finger Jointed Lumber. In addition to visual grade rules, regular, in-plant testing assures strong, reliable joints. Manufacturers sample production several times each shift and test for bond strength and adhesive durability. Structural finger joints must exhibit strength values more than twice the design value for the grade. Grading agencies review testing monthly.
"Structural end-jointed or edge glued lumber shall be permitted to be used interchangeably with sawn lumber members of the same species and grade."
For builders and code officials, the use of structually finger jointed lumber is accepted for building design in the US. All major code organizations reference the NDS or use similar language in their model Building Codes used in the US.
STUD USE ONLY. A Stud Use Only joint serves perfectly when the primary long term load is compression parallel to the grain. Also labeled VERTICAL USE ONLY, these joints are usually 3/8" to 5/8" long. The fingers may have blunt tips. The adhesives used are water resistant, but must be used inside. Stud use only lumber is available up to 2" x 6" x 12'.
CERTIFIED EXTERIOR JOINTS. Lumber with Certified Exterior Joints is not restricted to any type of loading. These joints will usually have jointed fingers 7/8" to 1-1/8" long. The adhesives used in the joints are waterproof and will not creep. This joint can be used in any width or length of American Standard lumber.
Both joint types may qualify for dimension lumber grades of Stud, 3, 2, 1 or Select Structural. Identify them by the information on the grademark. Without an approved grademark, it is impossible to tell structurally finger jointed lumber from nonstructural jointed products. Each piece of approved lumber must have a grademark identifying its use approval, mill I.D., grade, and the quality control agency.
Grades for structural Finger Jointed lumber use the same rule as unjointed lumber. The wood in the joints actually meets stricter requirements. Design values are also the same as those for unjointed lumber. This allows Structural Finger Jointed Lumber to be used interchangeably with unjointed lumber.
Lumber for construction use in the US is graded under the Department of Commerce Voluntary Product Standard PS 20-94. The American Lumber Standard Committee (ALSC) initiated this standard and is the Accrediting body for agencies that supervise grademarking of Glued Structural Lumber. TP has approval from the ALSC to supervise all approved finger jointing Quality Control Programs including their own Stud Use End Jointed Lumber Program.
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