Comparison to Typical Gutter Guard Covers
Typical gutter guard with needles
Most styles of full gutter protection (whether covers, caps or guards) do a fine job of keeping deciduous leaves out of the gutter. Their deficiency arises when seeds, pods, small debris and evergreen needles fall onto them. Since these products depend on surface tension to slide the rainwater around the front edge of the cover, small items such as needles, seeds, pods and debris often cling with the water and follow it right into the gutter. Snap-in style gutter screens will always allow debris through.
Typical gutter guard with overflow
Similarly, most brands of full gutter protection covers do a fine job of collecting rainwater when rainfall is light to moderate. The problems occur when heavier amounts of rain fall. Since they depend on surface tension to slide the rainwater around the front edge of the cover, when the water volume is more than the surface tension can hold, water simply flows over the front edge of the gutter. This defeats the whole purpose for having gutters in the first place.