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

https://www.blaze-bookmarks.win/single-ply-roof-guarantees-usually-cover-15-20-years-but-the-actual-roof-can-1

Single ply roof guarantees usually cover 15-20 years but the actual service life can stretch to 25-40 years with proper care. The warranty protects against manufacturing faults, not wear and tear or poor maintenance