Which framing method is required for the installation of gypsum board products in horizontal diaphragm ceilings?

The requirement for installing gypsum board products in horizontal diaphragm ceilings is based on ensuring proper support and load distribution for the boards. When framing is done perpendicularly to the orientation of the gypsum board, it allows for optimal structural integrity. This perpendicular framing method provides a more robust surface for the boards to attach to, minimizing the risk of sagging and ensuring that the load is evenly distributed across the ceiling structure.

By framing perpendicularly, it also facilitates better fastening of the gypsum boards, which improves the overall rigidity and helps in preventing cracking or dislodging. Additionally, this technique can enhance the acoustic properties of the ceiling assembly and provide better fire resistance, as the installation creates a more unified and solid surface.

The other framing methods, while they may have their own applications, do not provide the same level of structural benefit when it comes to horizontal diaphragm ceilings where gypsum board products are used. This specific requirement emphasizes the importance of following best practices in construction for long-lasting and effective building performance.