There are three steps to drying out your crawl space:

1. Stop moisture intrusion - through the foundation and through the vents.
Correcting rainwater management issues is typically easy and inexpensive. Often times this is simply a matter of creating a "reverse grade" that slopes away from your foundation, and re-directing downspouts. Of course, your gutter system has to be clear and in good working order.

And about those vents...seal them tight, once and for all.

2. Install a permanent vapor barrier...On the floor, the walls, and the columns.
There are a number of excellent crawl space vapor barriers available today. They have been engineered and manufactured to provide a permanent barrier that isolates your home from the earth and the environment.

3. Dry the air and the structure - mold can't survive below 60% humidity.
There are two ways this can be accomplished, and each has its own merits.

Option 1: Condition the Air
Conditioning your crawl space means treating it as if it were a basement. This is accomplished simply by adding one or more supply and return vents in your crawl, so that your system includes the crawl space air with the air in the rest of your home. Most HVAC systems can easily handle the additional square footage of your crawl because the encapsulation process significantly lightens the system load by dramatically reducing moisture in the crawl, and subsequently, in your home.

Option 2: Install a Dehumidifier
We use Oscar Air Dri-Crawl Space™ dehumidifiers in all our encapsulation projects. They have been specifically designed to withstand the rigors a crawl space environment demands, and are simply the best quality units on the market. The advantage with installing a proper dehumidifier is that 10-15 days after the encapsulation is completed, your crawl space will be at 55% humidity, and it is R.I.P. Mold...case closed.