Follow the water
Overflow can start with pitch, outlets, downspouts, or a roof valley.
Overflow isn't always a cleaning problem. Poor pitch, too few outlets, undersized downspouts, loose hangers, leaking corners, and concentrated water from a roof valley can all be involved.
When gutters are replaced with a roof or siding project, we plan the sequence around drip edge, fascia, and downspout locations. That avoids taking new work back apart later.
