Moisture in crawlspace; contractor bids are absurd, please advise

[Jack Gray]

Hello BP community,
I was wondering if I could get some help from some of the experts in the room.

A house I just purchased in central Virginia has a 900 sq ft crawl space with a poorly installed, torn vapor barrier. I noticed this during the inspection but didn't think it was a serious problem. Here's what the crawlspace looks like:

• White efflorescence on about half the concrete foundation blocks, indicating some water intrusion
• White mold in small patches in 1 or 2 spots on the floor joists
• A few droppings indicating a mouse or other pest is living there
• Condensation dripping off the AC duct work into a small puddle on the vapor barrier, plus one other small standing puddle with no visible source (not a leak, maybe recent heavy rain)

I obtained 3 bids from different companies to remove the existing vapor barrier and fully encapsulate the crawl space and install a dehumidifier (2 bids came in at $15k and $16k, one came in for $26k which also included mold remediation and a sump pump and trenching).
All 3 companies took air humidity readings and moisture readings of the wood joists and warned me about the long-term danger of my floor joists warping since they are made of composite wood.

To me, these 3 bids seem absurd, especially since as near as I can tell, I have a very normal crawlspace with just a tiny bit of water here and there and very little mold. I haven't noticed any issues with floors squeaking or doors out of alignment or foundation or drywall cracks.

4 Questions:

1. Is any of this even a problem? Should I be concerned?

2. What, if anything, should I do about this?

3. What is a fair price to for the work?

4. How should I find a reputable, and affordable repair company? I tried Angie's List already.  

Thank you for any help anyone can provide!