If the top of a window is 16" down from a 24" overhang, what should be installed?

In a situation where the top of a window is situated 16 inches below a 24-inch overhang, the appropriate installation is header flashing. Header flashing is specifically designed to be installed above windows and doors to prevent water infiltration. It directs water away from the window frame and protects the structure from potential water damage.

Given the significant overhang in this scenario, the header flashing will be critical to ensure that any rain or moisture that comes off the overhang does not seep into the window or the surrounding wall. Properly installed header flashing will create a barrier that shields the window while still allowing any potential water that may get past the overhang to drain away effectively.

The other types of flashing mentioned serve different purposes: standard flashing is more general and could be used at various points of the building envelope, base flashing is typically utilized at lower horizontal surfaces or where walls meet roofs, and starter flashing is generally used at the bottom of wall assemblies to help shed water away from the base. Therefore, for this specific situation with a focus on protecting the window under the overhang, header flashing is the correct choice.