What is mildew: Mildew is a fungus that thrives in warm, damp or moist environments with little or no air circulation and direct sunlight and feeds on the organic materials found in most paints. Mildew appears as a black, gray or brown discoloration and can be mistaken for dirt. To determine if it is mildew, apply a few drops of household bleach on the affected area. If it is mildew, the discoloration will lighten or disappear after a few minutes.
The best way to control mildew is to prevent it from forming in the first place. A clean, dry, light-filled area will not allow mildew to grow. Always clean and sanitize before painting an area. Do not paint over mildew, as it will grow through the newly painted surface and be even harder to control.
For interior painting, take preventative steps such as installing ceiling fans, exhaust fans, or dehumidifiers in rooms that are susceptible to mildew growth such as bathrooms, laundry rooms and kitchens.
Once you have taken care of the mildew prime the area and paint with a high quality latex paint. In bathrooms and laundry rooms, which are mildew rich environments, use Aura Bath & Spa paint which contains additives to inhibit mildew growth on the paints surface.