Does a manufacturer’s warranty cover algae growth on asphalt shingles?

Warranties vary, but there are some styles of asphalt shingles available with granules that have been treated to inhibit the growth of algae. Most warranties that offer this protection only cover blue green algae, or cyanobacteria, and normally just guarantee that no major discoloration will result from the algae. Whether the manufacturer will pay for replacement or just the cost of cleaning the shingles depends on the specific warranty.
