Which roofing system involves only a single field-applied layer of membrane material?

The roofing system that involves only a single field-applied layer of membrane material is single-ply membranes. These systems consist of large sheets of flexible membrane, which are adhered, mechanically fastened, or ballasted to the roof deck. This single layer is designed to provide waterproofing and protect the underlying structure from weather and environmental conditions.

Single-ply membranes are available in various materials, including EPDM (ethylene propylene diene monomer), TPO (thermoplastic polyolefin), and PVC (polyvinyl chloride), all of which are widely used in modern roofing due to their ease of installation, durability, and effectiveness. Their single-layer format simplifies the installation process as well as maintenance and repair, making them a popular choice in both commercial and residential applications.

Other options like built-up roofing typically involve multiple layers of materials, such as felts and aggregates, to provide robust protection but are more complex in composition. Metal roofing and tile roofing are structural systems that often consist of multiple components and layers to ensure weather resistance and structural integrity, further differentiating them from the single-layer nature of single-ply membranes.