For the last 30 years the process of roof washing has been proven to extend the life of the shingles. Many homeowners realize their roof is dirty or needs cleaning when they start to notice black streaks that are visible from the ground floor on either shingles or clay tiles. But what are these black streaks on the roof? These black stains are algae-like bacteria, called gloeocapsa magma. If not addressed, the algae can cause premature aging of the roof. These types of algae can have negative health effects, especially for individuals prone to allergy flare-ups. Algae particles give off airborne toxins around your property that can be harmful when inhaled, especially for a person who’s already sick.