Wood I-joists are a structural engineered wood product often used for joists and rafters in residential and commercial construction.

I-joists are made by gluing solid sawn lumber or laminated veneer lumber (LVL) flanges to a web made of plywood or oriented strand board (OSB). I-joists exhibit uniform stiffness, strength and are lightweight.

The availability of wood I-joists used as floor joists and as deep, roof joists that allow for extra insulation has made them popular.  They are also an economical alternative to open web steel joists.