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

https://oscar-wiki.win/index.php/Do_Certified_Installers_Really_Make_a_Roof_Last_Longer%3F

Single ply roof guarantees usually cover 15-20 years, but the actual service life often stretches to 25-40 years. Guarantees focus on materials and workmanship, not wear and tear or maintenance