Single ply roof guarantees usually cover 15-20 years, but in reality, these...

https://tessatopmaid.com/approved-contractor-schemes-do-they-actually-matter-for-guarantees/

Single ply roof guarantees usually cover 15-20 years, but in reality, these roofs can last 25-40 years if looked after properly. Guarantees focus on materials and installation, not daily wear and tear