Engineered wood rimboard is a structural component that works with floor or roof framing members. EWP rimboard is manufactured to match the depth of wood I-Joists and LVL. A rim joist is a structural member that runs perpendicular to and is connected to the ends of floor or roof joists. The terms rimboard and rim joist are often used interchangeably.
Engineered wood rimboard products should be used with engineered wood joists. Solid sawn rim boards may shrink at a different rate than engineered wood products resulting in dimensional incompatibility. See WIJMA Rimboard position statement.