We built our home 10 years ago. My wife started getting sick a few years into our living there, and it took us a while but we figured out that it was likely mold that was causing her grief. We've since moved out of the house and she's much, much better now. So we're at the point now where we're fixing the house. We had our crawlspace flooded before we moved in 10 years ago, so that's one source of mold as there was a good deal of debris there that molded and counts were very high there. Also we had a few other water intrusions that we have addressed as well.
So, first question: we live on the coast of California, and as such, outside humidity can range from 90+% to 25% depending on the day. During the summer, like today, it ranged from 90% this morning, to 50% right now (mid-day) and will probably drop a bit more before the fog comes in again tonight. I'm wondering what is the best thing to do in the crawlspace to keep the mold to a minimum - seal the vents, or add fans to keep air moving through. I can seemingly argue both ways, but I'm not sure if moving humid air is better than stale, more dry air.
Our IH is recommending against a vapor barrier on the floor of the crawlspace, however, due to it trapping moisture below it and contributing to more growth. He's suggesting fans to keep air moving through the crawlspace.
Any thoughts? I apologize if this is an elementary question, I can see why one would seal crawlspaces when humidity is always high, and leave them open when humidity is always low, but we fluctuate so much I'm not sure what is better in this case...
I have many more questions including whole house dehumidification, vapor barriers in attics, and air purification...but I'll research them a bit more before asking. Thanks!