By what falls on the roof
| Debris | Types that handle it | Types that struggle |
|---|---|---|
| Pine and fir needles | Fine micro-mesh | Coarse screens, brush inserts |
| Broad leaves | Mesh, reverse-curve hoods, screens | Foam (leaves sit on top) |
| Seeds, catkins, flowers | Fine mesh | Screens with large openings |
| Roof grit and pollen | Fine mesh, brushed off now and then | Every type collects some |
How each type works
- Screens: perforated panels; simple and inexpensive, but small debris passes through.
- Mesh and micro-mesh: metal mesh in a rigid frame; the finer the mesh, the smaller the debris it stops.
- Reverse-curve hoods: water follows the curved nose into the gutter, debris slides off. In the hardest rain some water can run past the curve.
- Foam and brush inserts: fill the trough itself; easy to fit, and lifted out to clean.
Limits
A guard does not fix pitch, size or loose hangers, and it does not prevent ice. University of Minnesota Extension traces ice dams to heat escaping from the house, not to the gutter. Debris also builds up on top of guards and in the downspouts below them, so a guarded gutter still needs a look and, from time to time, a cleaning.
Before you buy
Guards are often sold during a visit to the house. The FTC's Cooling-Off Rule lets you cancel a purchase of $25 or more made at your home until midnight of the third business day, and the seller must give you a cancellation form. Get the warranty in writing: what it covers, for how long, whether it transfers when the house is sold, and how the guards fasten at the roof edge.