Debris and Drainage Conditions That Affect Flow
Drainage troughs and outlets collect whatever materials land on the roof surface or wash down the valleys. Depending on what surrounds a specific parcel, buildup can vary significantly from one property to the next:
- Fallen leaves, small twigs, and airborne organic matter settling along horizontal runs.
- Windblown dust, roof grit, and seed pods accumulating near drainage drops.
- Denser sludge forming in low-slope troughs where standing moisture remains after storms.
- Physical obstructions lodging directly over downspout openings and restricting flow.