was planning to lay down visqueen or similar, 6mil poly or so

Not good enough. Needs a trowel on vapor system and or roofing mastic plus 6mil minimum.

This site is an excellent source for moisture issues over concrete slabs. Check out what happed to this pooor soul.

http://www.wagnermeters.com/concretefor ... -t-66.html

Why not use Bostiks best. It is an adhesive and vapor barrier in one.

Bostiks Best is not sold as an adhesive and vapor barrier in one. Bostik does state that when cured as an adhesive, it is water proof. But its one function is as an adhesive, not a combo adhesive/vapor retarder. To use a vapor retarder with Best, you would use Bostik MVP4.

Bostik has come out with "Vapor Lock" and "Ultra Set". Both are combination Urethane adhesives and vapor retarder membrane.

so far I have not been able to find bostick products here. The Roberts 1408 is the best I have found so far.

my slab on grade already has a poly layer under it. i don't know if a cacl test can be done, but I could probably tape some plastic down and see how that fairs.

I am leaning towards leveling the slab, grinding down the highs and patching the lows, and applying roberts 1408 and the 5/16" bamboo over that...?

You can order cacl tests online. All you need to do to figure out the results is a gram scale and a calculator, and some places sell those as well. Lots cheaper than doing the floor over.

http://www.vaportest.com

I taped about a 2' x 2' piece of poly to the slab and after 24 hours it didn't have any moisture, I left for a vacation, and after 7 days it still didn't have any moisture. I'm thinking the Roberts 1408 or similar directly onto the slab? In leiu of not having the strap clamps, will lots of blue tape work?