Single ply roof guarantees, usually 15-20 years, cover specific materials and...

https://jasperotbu571.iamarrows.com/single-ply-roof-on-an-industrial-estate-with-metal-roofs-too-who-coordinates-it

Single ply roof guarantees, usually 15-20 years, cover specific materials and workmanship but don’t always reflect the full service life, which can stretch to 25-40 years with proper care