Abstract: A particleboard web member interconnects a pair of wood chord members by means of glued tongue and groove joints to form an I-beam or roof truss. A pair of grooves in each chord member receives a pair of parallel tongues on the web member. The grooves are inclined from top to bottom to bend the tongues out of parallelism and form self-locking dovetail-type joints which hold the members together in assembled relation without the use of external clamps while the glue is setting.