What is the standard in North America for the orientation of the outer layer of plyform?

The standard for the orientation of the outer layer of plywood in North America dictates that the grain of the outer layer must be parallel to the long dimension. This alignment enhances the strength and stability of the plywood, making it more effective for construction purposes. When the grain runs parallel to the long dimension, it allows for greater load distribution along the length of the panel, providing increased resistance to bending and warping.

In contrast, options with diagonal grain orientation or horizontal grain running across the surface do not provide the same structural benefits. Diagonal grain can lead to uneven load distribution and may compromise the panel's strength. Similarly, a horizontal grain alignment does not align with the standard practices for maximizing structural integrity in plywood applications. The choice suggesting that the orientation does not affect strength fails to recognize the importance of proper grain alignment in plywood performance, which is crucial for durability and resistance to various external stresses.