Quick Overview

Block and strap bridging is installed to prevent joist rotation and lateral movement. Solid blocking, a field-cut track or joist section, is welded or screw-attached between the first and last two outer joist bays and at a maximum of 8' O.C. along the strap, over all interior supports and adjacent to floor openings. Two-inch wide corrosion resistant strapping is also screw-attached or welded to the bottom of every joist flange. Lateral support on the top flanges is usually provided by sub floor or deck material. Spacing of bridging must be calculated based on the required strength. In general, bridging is installed at a maximum of 8' O.C. spacing pendicular to the joists. For example, an 18' joist span would require two bridging runs at 6' O.C. spacing. Where the sub-floor or decking does not provide lateral support, strap must also be installed on the top flange of the joist.