Charlie,

In my 20+ years of crawling foundations, I could count on my hand the number of homes I've seen with a vapor barrier.

Those that did have them were not installed properly. Large puddles of water is seen on top of the vapor barriers that I've seen or pictures of.

Here in our area, most HI's recommend leaving the foundation vents off all year to allow ventilation of the crawlspace.

I've seen many homes that were soaking wet and condensation dripping off the floor joists due to having no ventilation. You take the vents off, place a fan under the house and the crawlspace would dry out in just a couple of days.

We used to do this all the time doing termite treatments. Some houses would have water ponding along the inside walls of the foundation. Most were due to improper drainage. Regardless, we could not termite treat or inject chemical into standing water so we had to take measures to get the soil dried out. AIR MOVEMENT worked great with any moisture problem.

There is some homes I've seen that actually had some type of fan system that was designed to fit in the foundation vent opening to push the air. We used to see them advertised in a PC magazine all the time. Some PC companies installed them in the slow times of the year.

Rick