Barnes Exterminating offers free inspections and estimates to detect any moisture, mold, mildew, and fungus in your home. Ground covers are placed on the soil in the crawl space to reduce the amount of moisture evaporating into the house. Excess moisture can lead to mildew and rot in the crawl space. Excess moisture can also cause heavy condensation on windows in the winter, mildew in the closets in the summer, and even allergy problems due to molds which grow in damp wood. We cover about 80 to 90% of the crawl space with a polyethylene plastic barrier. The purpose of the plastic is to reduce the surface area in which moisture evaporates. It is normal to see water beads collecting under the plastic this is a sign that the barrier is working.
We also use Timbor, a chemical that stops the growth of moisture, to spray in your basement or crawlspace as well as other wood destroying insects.
See our link for moisture control on our home page for more informantion on foundation vents.