A horizontal structural member used to support and stabilize I-joists along their length. Girders used to support I-joist floor assemblies are typically made from glued-laminated lumber, parallel strand lumber, or multiple pieces of laminated veneer lumber (LVL).
Laminated veneer lumber - is an engineered wood product created by layering dried and graded wood veneers with waterproof adhesive into blocks of material known as billets. Cured in a heated press, LVL is typically available in various thicknesses and widths and is easily worked in the field using conventional construction tools. LVL is also known as structural composite lumber (SCL).
Parallel strand lumber (PSL) - is a high strength structural composite lumber product manufactured by gluing strands of wood together under pressure. It is a proprietary product marketed under the trade name ParaIlam®.
Glu-lam - is a stress-rated engineered wood product comprised of wood laminations, or "lams," that are bonded together with strong, waterproof adhesives. Glulam components can be a variety of species, and individual "lams" are typically two inches or less in thickness. ANSI/AITC A190.1 includes requirements for sizes, grade combinations, adhesives, inspection, testing and certification of structural glued laminated timber products.