901- 643-9460
Algae Discoloration
of Roofs
Asphalt Roofing
Manufacturers Association
1156 15th St., NW, Ste. 900
Washington, DC 20005
Tel: (202) 207-0917 • Fax: (202) 223-9741
www.asphaltroofing.org
For many years, roof discoloration caused by algae has been observed throughout the United States and Canada. This is commonly referred to as “fungus growth.” The discoloration usually has a brown to black appearance, and may be mistaken for soot, dirt, moss, or tree droppings.
The primary species of algae being observed is Gloeocapsa Magma. This type of algae is contained in and transported through the air, and tends to collect and grow upon roofing structures. Natural pigments produced by this algae may cause a white or light colored roof to gradually turn dark brown or black. The algae discolorations should not be confused with moss or tree droppings, which typically produce only localized discolorations.
This type of roof discoloration has been most widespread in the Gulf States and along the Northwest and Eastern Seaboards. It is not, however, confined to only these regions. Algae growth occurs to varying degrees in all regions of the country, especially those subjected to warm, humid conditions. It should be noted that almost all types of roofing systems are susceptible to algae discoloration. It is, of course, most readily visible upon white or pastel
roofs, while it is not so visible upon darker shades of roofing.
Algae discolorations are difficult to remove from roofing surfaces, but can be removed with a
safe specialized roof treatment. This specialized process is not recommended for the average individual and you should seek out and search for a trained company that provides this specialized roof treatment and algae removal service.
Depending on the amount of roof algae discoloration and the age of the roof one application
may not completely remove the algae discoloration and completely eradicate its root system
from your asphalt roof. In some cases two to three applications may be necessary.
If you chose to attempt this specialized roof cleaning process on your own you must be very careful as to avoid damage to other parts of the building and its surrounding landscape
Avoid scrubbing the surface, as this friction may loosen and remove granules. If possible,
always work from a latter and/or walkboards to avoid direct contact with the roof surface. Observe all possible safety precautions when working on or near the roof.
After applying the proper cleaning solution you made need to rinse your roof.The rinse process will make the roof surface slippery and potentially hazardous to walk on during treatment.
This specialized roof cleaning process when performed by a trained roof treatment and
cleaning service provider should keep your roof looking great and prevent roof staining for
several years to come.
Caution!
High pressure washing systems for algae removal should not be used. High pressure washing systems should never be used on any roof or asphalt roofing.
Ref: ARMA
What You Need To Know About Algae Discoloration
