Engineered Beams Mixed with Conventional Framing

Recently a client came to us for a structural consultation concerning a noticeable gap in the floorboards of their home. Upon further inspection of the floor joists and beams below, the reason for the gap became evident. During the framing of the floor, the tops of the joists were installed level with the top of the LVL beam (Laminated Veneer Lumber). Over time the joists became significantly offset from the beam because conventional wood joists shrink more than LVL beams. Additionally, the plywood subfloor did not span over this beam and joist connection, allowing the flooring above to separate. LVL beams should be installed dropped ¾” below the top of the joists to account for the size change likely to occur over time, and the subfloor should also span over the connection a minimum of 12” in each direction. These small construction details cannot be overlooked and are important for a long-lasting, high-quality floor.

Team Engineering understands the importance of adding relevant and clearly displayed details to ensure designs are constructed in the intended way. This is just one way we at Team Engineering passionately serve our clients and deliver excellence.

Photo: Standard detail of typical flush LVL beam and conventional joists

Ali McNamara

Engineering Technician