The strength of a gutter system largely depends on the materials used and the design. However, when it comes to durability and longevity, Yankee gutters and K-style gutters are among the strongest. Yankee gutters are built into the structure of the house, making them less vulnerable to damage from storms or wind. They can be lined with durable materials like EPDM liquid rubber or a liquid membrane to increase their lifespan. On the other hand, K-style gutters, named for their shape that resembles the letter ‘K’, are made from heavy-duty materials like copper or galvanized steel, and their design offers high water carrying capacity and resistance to damage.