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

https://www.random-bookmarks.win/single-ply-roof-guarantees-often-15-20-years-cover-materials-and

Single ply roof guarantees often cover 15-20 years, but the actual service life can reach 25-40 years when properly looked after. Guarantees focus on defects, not wear and tear