A single-ply membrane is a factory-manufactured sheet of polymeric material, such as EPDM, PVC, or TPO, designed to waterproof a roof in one layer. Unlike traditional built-up roofs that rely on multiple layers of asphalt and felt, single-ply systems are installed in a single thickness and joined at the seams using heat welding, adhesives, or specialized tapes.
We're tearing off the old built-up tar roof and putting down a white TPO single-ply membrane to reflect the heat.
Related terms
Single-ply roof
A roofing system that relies on a single layer of flexible synthetic membrane to provide waterproofing.
Field seam
A joint between two overlapping membrane sheets created on the job site.
Sheet membrane
Waterproofing supplied in rolls of factory-made sheet with a controlled thickness, joined at overlapping laps.