What characteristic defines a water shedding roof system?

A water shedding roof system is characterized by its reliance on gravity to facilitate efficient drainage of water. This means that the design and slope of the roof are intentionally structured to direct water away from the roof surface and towards roof edges or gutters. The use of gravity is essential for ensuring that water flows off the roof rather than pooling or penetrating the roofing materials, which could lead to leaks and water damage.

Non-porous materials, while important for preventing water absorption in certain roofing systems, do not solely define a water shedding roof. Absorption of water is actually counterproductive to the principle of water shedding, as it can lead to leaks and deterioration of the roof over time. Panel interlocks may contribute to waterproofing in some roof designs, but they do not define the fundamental concept of shedding water. Thus, the correct answer focuses on the essential mechanism of drainage in a water shedding roof system, which is its dependence on gravity.