Algae-resistant Roofing System

3M Industrial Mineral Products Division, St. Paul, Minn., offers a technical solution to the roof algae problem. When Scotchgard Algae Resistant Roofing System is uniformly distributed across the surface of the shingle in combination with standard colored granules, it offers long-term algae and stain resistance. This allows a roof to retain its aesthetic appearance and lower overall cost by eliminating repeated cleanings. In addition, the Scotchgard is environmentally responsible — it won’t harm plants or shrubs. Brands with the Scotchgard AR system include PABCO and Malarkey.