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

https://knoxuqsk688.cavandoragh.org/do-certified-installers-really-make-a-roof-last-longer

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