What type of roofing system is created by covering 17" with mineral and using a 19" selvage edge?

The roofing system created by covering 17 inches with mineral surfacing and using a 19-inch selvage edge is accurately identified as a two-ply roofing system. A two-ply system consists of two layers of roofing materials, which enhances durability and waterproofing capabilities. The first layer typically serves as a base, while the second layer provides added protection against the elements and improves the overall structural integrity of the roof.

In this scenario, the specifications of 17 inches for coverage and a 19-inch selvage edge indicate a method of overlapping, which is a hallmark of a two-ply application. This overlap helps to create a weather-tight seal that prevents water infiltration, characteristic of effective roofing systems.

Using a single layer would not provide the same level of protection or durability, while fully adhered roofing involves a different application technique that is not specified here. Tin roofing systems also represent a distinct material and application method, differing significantly from the details provided in the question. Therefore, the combination of the measurements and the use of the selvage edge points directly to a two-ply roofing system as the correct classification.