Watching for any early sign of water intrusion and acting quickly to correct the issue will reduce risk of a major mold event. It only takes the presence of moisture for a few days to promote the growth of mold.
Mold spores are present everywhere, all of the time; add water, have mold. The use of a high quality acrylic house paint containing active biocides to prevent mold growth on the exterior of your house is important.
Mold remediation means removing any contaminated or wet building material or contents and then hand scrubbing all surfaces with detergent and a mold killing biocide to kill any mold spores still present.
There are several mold inhibitive clear coats available for decks, stairs, walkways and drives. The long term performance of these products does not eliminate the need for annual maintenance cleaning however.
The most effective approach for mold control is to keep it outside where it is more easily dealt with. An annual cleaning and maintenance procedure performed by John Grey Painting will limit the need for any mold remediation treatment.