If you live in an area which experiences humidity during the summer seasons, chances are that you’ve seen stains or spots which appear to be mold on the roof. The mold on the roof is usually not mold at all, but rather a blue-green algae. This algae (Gloeocapsa Magma) might look rather ugly, but isn’t really harmful to your roof.
To Remove the Algae Stains
To remove the algae stains from your roof, you’ll want to get a sprayer which you will fill with a solution of 50 percent bleach and 50 percent water. While bleach does NOT completely take care of mold, it will take care of algae.
Before spraying anything down, you’ll want to protect your plants trees and landscaping around the foundation by hosing them down with water, which will help minimize damage from the bleach solution. Covering them with plastic can also help. Carefully spray down the roof and allow the bleach to kill the algae. If your roof also has a moss problem, scrub off as much moss as possible before applying the solution. Let it set for about 15 minutes before rinsing, and be sure to hose down your plants again when you’re finished.
Prevent Algae Growth
Installing a new roof laced with copper granules is optimal, but not usually the cheapest option, since copper is lethal to algae. The next best option is to install metal zinc strips
Always use common sense and safety equipment. If you suspect the spots on your roof are actually mold, contact a professional mold remediation company to perform an assessment before you begin your project.