Single ply roof guarantees usually cover 15-20 years, but the actual service...

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

Single ply roof guarantees usually cover 15-20 years, but the actual service life can stretch 25-40 years with the right care. These guarantees focus on materials and installation, not wear and tear from weather or neglect