You know you have algae, mold, and fungi growing on your roof if your roof has discolored to a dark brownish color, has a greenish tint, or has dark streaks running down the pitch. Leaving it alone is not only unsightly, but it can damage your roof, especially if you have cedar, wood, or asphalt shingles. There are several methods for cleaning this organic material from your roof that are simple and easy to accomplish.
The best way to kill the organic material is to have your roof cleaned by a professional roof cleaner. A wet roof is dangerous, and is best left to a professional with experience. Also, inexperience can easily damage your roof, so let a professional use his expertise to get the job done without damaging your property.
Usually the professional roof cleaner will use a cleaning agent to kill the algae. mold, and fungi growing on your roof. A bleach solution is sometimes used, but this has its disadvantages. For one thing, bleach can ruin your landscaping with water run off. When used improperly, it can even cause irreversible staining to your roof. Instead of a bleach solution, the professional should use a special cleaning solution made specifically to treat and kill your particular infestation. While there are several fungicides and mold killers on the market that you can buy from your local hardware store, the professional roof cleaner should have a tried and true solution that is proven to work in your climate zone. Different climates can create different algae, mold, and fungi infestations, and knowing which to treat is key.
Zinc and copper have been shown to significantly reduce the amount of algae, mold, and fungi that can build up on your roof. Once the infestations have been killed and cleaned away, look into getting copper flashing installed around your chimneys or installing zinc or copper panels on your roof. Something as simple as installing a copper panel on the underside of the top most line of roof shingles so that it peaks out just slightly, is enough to allow rainwater to move the copper molecules down the pitch of the roof and help prevent and slow unwanted algae, mold, and fungi growth. If this is something that you would be interested in, talk to a professional roofer or roof cleaner.