Moisture and shade increase the chance of mold and mildew. SPPI exterior painters would never suggest for you to paint over it, because it will not do the trick. This pesky problem will just come through that fresh coat of paint. Deal with the problem before repainting. You can use a fungicide like chlorine bleach or opt for a commercial solution to kill these fungi. Know more about other painting tips from our expert interior and exterior painters by contacting SPPI.