Single ply roof guarantees, typically 15-20 years, cover defects but not the...

https://redditchstandard.co.uk/lifestyle/how-long-does-a-single-ply-membrane-roof-really-last-a-building-owners-guide/

Single ply roof guarantees, typically 15-20 years, cover defects but not the full life the roof can deliver, which often stretches to 25-40 years with good care