What roofing term describes layers applied directly to a prepared substrate?

The term that describes layers applied directly to a prepared substrate is single-ply membranes. These systems consist of a single layer of roofing material that is often made from thermoplastic or thermoset materials. They are designed to be installed directly on a clean and prepared substrate, typically including insulation boards or a deck. This method of application helps in achieving a water-resistant barrier with fewer seams, thus minimizing potential leaks.

Single-ply membranes also offer advantages like weight savings, flexibility, and ease of installation, which make them a popular choice in modern roofing. They can be mechanically attached, fully adhered, or ballasted, allowing for versatility in application based on specific project requirements. This versatility and ease of installation are key features that characterize single-ply systems compared to the other roofing types mentioned.

Other options such as shingle roofing and built-up roofing involve different methodologies and materials. Shingle roofing consists of overlapping pieces typically made from asphalt or other materials, while built-up roofing involves multiple layers (or plies) of roofing material that are installed in a more complex manner over a substrate. Metal roofing involves panels or tiles made from metal, which require different installation techniques as well. Thus, single-ply membranes specifically refer to that unique application process directly onto