The Slide Path of Your Roof Means Everything, For Shedding. think about it: debris generally slides down your roof. The steeper the roof, the easier it is for stuff to fall off. We try to get that slope to be unbroken once it reaches your gutter. Why? So it doesn't get hung up on the gutter guard!
Debris will not shed if it's too shallow. Image standing on a steep roof. You're at the top looking down...wouldn't take much for you to strt falling, right? Now imagine you're on a flat roof. Different feeling! Same basic idea for the tree debris that falls on your roof. The steeper your gutter guard is installed, the easier it will shed debris. Now this probably sounds like plain old common sense, but it's important to distinguish between the "angle of repose" and "angled" as some of our competitors have noticed that our stuff works a lot better and are copying some of what we say.
If a guard is just angled or sloped, but not enough, it still collects debris like a shelf. It's got to be the same slope as the roof or more.
What is the angle of repose? It's the angle at which shedding will occur. For needles, seeds and roof grit that's about a 5/12 roof pitch.
As a great example one competitor boasts "LeafFilter is installed at the same 11-degree angle every time, which is the ideal angle for shedding debris."
Well it's half true. It is prebuilt with an 11 degree angle. That's a 2/12 pitch, which in roofing parlance is considered a "flat roof" because you shouldn't even apply a non membrane roof to it. Example here: