Installation Guidelines
Question:
What are the requirements on the permanent bracing of bottom chords? Can gypsum board diaphragms be used?
Answer:
Yes, gypsum board diaphragms can be used to brace the bottom chord of the truss in most cases. However, in high wind or seismic areas, the gypsum board may not be sufficient. Therefore, continuous lateral reinforcement may also be required. The building designer must review the requirements applicable to your project and adjust the design accordingly.
Bottom chord bracing recommendations are outlined in appendix A of the Truss Plate Institute's ANSI/TPI 1. This issue is also covered in SBCA’s BCSI-B3 Summary Sheet.