Colorbond is a popular building material because of its durability and low maintenance. Commonly used for sheds and roofs, Colorbond simply needs the occasional rainfall or hosing down in order to stay clean. However, as with almost any other material, Colorbond can be susceptible to fungi if the right conditions exist. If you suspect that a fungus, such as mold or mildew, lives on your Colorbond, do not panic. A simple solution to test and to treat the area exists.
Put on protective eyewear and gloves.
Test the area by placing a drop of undiluted bleach on the suspected fungus. Wait a few moments to see how the area dries. A clean, dry spot indicates the likelihood that the substance is indeed a fungus.
Dilute the bleach so that the hypochlorite content is only 2 percent of the new cleaning solution. As most household bleaches contain approximately 6 percent hypochlorite, mix one part bleach with two parts water.
Add a small amount of household detergent such as dish soap to the diluted bleach solution to improve wetting. This step is optional.
Apply the bleach solution by using a soft-bristle broom to scrub the solution onto the entire area affected by the fungus. Saturated the area well, and allow the solution to sit at least three to five minutes.
Rinse the entire area thoroughly with water.