Single ply roof guarantees typically cover 15-20 years, focusing on material...

https://www.apu-bookmarks.win/single-ply-roof-guarantees-usually-cover-15-20-years-but-the-actual-roofing

Single ply roof guarantees typically cover 15-20 years, focusing on material defects or installation issues. But the actual service life can stretch 25-40 years if the roof is well maintained