Colorado Building Wood floating basement floors

My son is looking to purchase a home in Castle Rock, Colorado.
A 1993 home with basement. Expansive soil conditions are present. Existing basement floor is a floating wood floor. What are the pros and cons of this vs a slab construction. Now interject radon over [FONT=Times New Roman]*4 pCi/L. * Accepting advise suggestions and comments? [/FONT]

Hi Milton,
The reason for the structural floor which is probably steal joists with a wood deck over a crawlspace is due to the expansive soils as you stated. The bentinite clay soil will expand quite a bit when wet/moist. Concrete floors will not survive. So depending on the soil conditions and reports some areas are built like that. He won’t have to worry about the floor cracking, settling or heaving.
There is usually a crawlspace underneath. Space will vary from about 6" below the framing to a couple of feet. There is also usually a vapor barrier.
There should also be a powered ventilation system with a supply and exhaust at opposite ends.
As far as the Radon. Most of Colorado is in Zone 1. If the results recommend mitigation the piping should be below the subfloor and vapor barrier, standard installation.
Let me know if you have any other questions.

And some builders here will tell you that the moisture ventilation system under that floor (but above the vapor barrier) is a Radon mitigation system. No dice.

I have also had realtors say the same thing.