Crawl Space Issues and Solutions
A crawl space is an area of limited height underneath the floor of your house. It typically allows just enough room for someone to crawl underneath, hence the origin of its namesake.
Excess water often invades crawl spaces, which can lead to mold and other issues. If moisture is a problem, it is important to identify the source of water. If the moisture is the result of poor circulation, consider installing a plastic vapor barrier on the floor. This will help keep the space dry. If water is coming through the foundation, you'll need to repair the foundation, something that requires professional help. Once any cracks are fixed, consider installing a French drain around the perimeter of the house to direct water away from the foundation.
It is important to consistently maintain a crawl space. If the process of checking under your home every few months becomes arduous, then you may want to consult a professional who will provide routine maintenance.
See also: Preventing Basement Moisture