It is a species of cyanobacteria. Cyanobacteria are an ancient line of photosynthesizing bacteria, which photolyze water generating oxygen gas. Ancient cyanobacteria were ancestral to the chloroplasts of all plants on earth. This has gained notoriety in the Southeastern United States, but, it is also spreading throughout the Midwest. This particular type of cyanobacteria is responsible for creating black stains and streaks on roofs. The bacteria accumulate over time as it feeds on moisture and calcium carbonate. This accumulation begins to show the black stains as the cyanobacteria develop their dark and hard UV-protective outer coating. The main reasons for the rapid spread and noticeability of these cyanobacteria are thought to be:
1. Rising humidity and temperatures combined with more and more bacteria spores promotes their spread with these favorable conditions. 2. Fiberglass shingles (the most commonly seen among today's residential homes) are made with limestone as a filler (in the asphalt). These shingles hold moisture and organic "bacteria food" material longer (especially on the North-side in the Midwest) than the paper/asphalt/ceramic shingles of 20+ years ago. Additionally, these particular bacteria enjoy the limestone as a food source. Once the bacteria have become noticeable, the stains will continue to worsen year to year. There is debate over the actual harmfulness of this particular bacteria to roofs, as there is little supportive scientific research. However, most "experts" within the subject area conclude the bacteria to be harmful, if left untreated, as the growth holds moisture within shingles causing premature aging, rotting, and/or granule loss.Let alone the roof damage it is just plain ugly and unhealthy.These micro-organisms continue to breed and then die off using the dead carcass as a food source.You can combat this with nano particles of titanium dioxide.These particles once on your roof will constantly react with sunlight to make hydrogen peroxide as long as there is sunlight on the treated area.It will prevent regrowth as well -
How can Tio2 help?Basically if you are applying hydrogen peroxide in nano particle sizes that will prevent this from happening.
If your roof is bad it will take two to three applications to remedy the problem.
ONCE IT IS CLEAN EVERY TWO YEARS APPLY TO ROOF