A two-piece gutter system is not seamless, which can cause leaks to frequently occur. A two-piece system usually consists of a seamless open gutter bottom that channels the water and a separate gutter cover that is attached to the roof and hangs over the gutter.
Debris and leaves that do not slide over the gutter cover can become trapped, causing build-up and clogs. Plus, two-piece gutter guards can detach in high winds, and their design makes them vulnerable to damage from ladders and tree limbs.