Symptom
Tiger striping
Black vertical streaks on gutter faces. Oxidized aluminum + airborne dirt. Standard cleaning doesn't remove it.
Vertical black streaks on the face of aluminum gutters, caused by oxidized aluminum particles mixed with airborne dirt running down the gutter face during rain. The streaks are on the gutter paint or unpainted aluminum, not the house.
Standard gutter cleaning doesn’t remove tiger striping — requires a dedicated wash with a gutter-specific cleaner (typically a mild acid or oxalic-acid-based product) and soft cloths. We can quote tiger-stripe removal as an add-on after gutter cleaning.