Single ply roof guarantees usually last 15-20 years, but the roof’s real...

https://alpha-wiki.win/index.php/Years_0_to_10_%E2%80%93_What_Design_Mistakes_Show_Up_First_on_Single_Ply_Roofs%3F

Single ply roof guarantees usually last 15-20 years, but the roof’s real service life can stretch to 25-40 years. Guarantees cover materials and workmanship, but don’t always factor in weathering or maintenance