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

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

Single ply roof guarantees often cover 15-20 years, but in reality, these roofs can last 25-40 years with the right care. Guarantees focus on materials, not wear and tear or poor maintenance, which shortens life