Single ply roof guarantees usually cover 15-20 years, focusing on workmanship...

https://www.unitedbookmarkings.win/single-ply-roof-guarantees-usually-cover-15-20-years-but-the-actual-roof-can

Single ply roof guarantees usually cover 15-20 years, focusing on workmanship and materials, but the real service life often stretches to 25-40 years with proper care