For maximizing exposure of wood shingles installed on a wall, the maximum exposure for a double-course application is:

In double-course applications of wood shingles, maximizing exposure means allowing the shingles to cover as much wall area as possible while still providing weather protection. The maximum exposure for a double-course application is typically around 7 1/2 inches. This measurement ensures that there is sufficient overlap between the courses to maintain water resistance and avoid leaks.

If the exposure exceeds this measurement, it can compromise the shingles' effectiveness against weather elements, allowing water to penetrate through the joints where the shingles overlap. This height also aligns with standard practices in carpentry and siding installation, providing not just aesthetics but also functional durability. Thus, for ensuring proper installation while maximizing exposure, 7 1/2 inches is the accepted limit.