Which type of roofing system typically involves individual pieces for flashing?

The correct answer is steep slope roofing, as this type of roofing system generally makes extensive use of flashing, which is typically installed in individual pieces. Steep slope roofs are designed with a pitch that promotes water drainage, making it essential to have effective flashing at the joints, protrusions, and transitions to prevent water infiltration. This flashing is often custom-fitted and installed in discrete sections to ensure seams are adequately sealed and protect vulnerable areas.

In contrast, flat roofing systems usually utilize continuous materials that can cover larger areas without the need for numerous sections of flashing. Single-ply roofing incorporates large sheets or membranes that are sealed together, which can reduce the number of individual flashing pieces required. Metal roofing can also utilize larger panels that interlock and overlap, similarly minimizing the requirement for separate flashing elements. Thus, steep slope roofing stands out for its reliance on individual flashing pieces, making it unique among the options provided.