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

https://front-wiki.win/index.php/IKO_Group_Single_Ply_Lifespan_Claims_%E2%80%93_What_Do_They_Actually_Say%3F

Single ply roof guarantees usually cover 15-20 years, but the actual service life can stretch to 25-40 years with proper care. Guarantees focus on materials and workmanship, not wear and tear or maintenance issues