Finger Jointed Material
Question:
Is finger-jointed material allowed in the manufacturing of trusses?
Answer:
Finger-jointed lumber seems to come with a lot of questions. Can you use it in structural chords and webs? Can you use it in tension? Isn’t it for vertical use only, like gable end studs? Can you make your own? Can the plates grip in a finger joint?
Section 3.4.6 of the Truss Plate Institute's ANSI/TPI 1 addresses the use of finger-jointed lumber in trusses:
Structural finger-jointed lumber shall be permitted to be used interchangeably with solid-sawn members of the same grade and species if the finger joints are manufactured with an adhesive meeting the requirements of ASTM D2559 and also meeting, for trusses to be used in fire-resistive construction, the high temperature performance requirements of the American Lumber Standard Committee. Structural finger-jointed lumber shall be identified by the grade mark of, or certificate of inspection from, a lumber grading or inspection agency that has been approved by an agency accredited by the Board of Review of the American Lumber Standard Committee. The grade mark and certification of inspection for structural finger-jointed lumber shall indicate that joint integrity is subject to qualification and quality control. Finger-jointed lumber marked “STUD USE ONLY” or “VERTICAL USE ONLY” shall not be used in metal-plate-connected wood Trusses. Finger-jointed lumber marked "Non-Heat-Resistant" or "NON-HRA" shall not be used in metal-plate-connected wood trusses to be used in fire-resistive construction.