• continuously high humidity. As the humidity increases, mildew growth becomes more rapid.
• high average temperature. Optimum temperature for mildew growth is 77ºF.
• poor ventilation. Still air increases mildew growth.
• composition of surface. Mildew will grow on any surface that provides a nutrient, even dirt.
• light colors of paint film. Colors that do not absorb the sun’s heat provide a surface for mildew growth. Dark colors become hot and discourage mildew growth.

Wash mildewed areas with a solution of one part household bleach and three parts water.¹ This will destroy mildew and bleach stains caused by mildew growth. Apply solution by brush or a garden sprayer apparatus. Heavy mildew may require additional applications, and scrubbing may be required. Flush area with clean water to remove bleach solution. Allow to dry thoroughly.