Where is the best place to install a vapor barrier? I've read that a person can put it between the poured foundation and the studs or between the studs/insulation and the drywall. What thickness would you recommend? I assume that the best way to install the barrier is to run it vertically. Correct? What kind of tape should a person use to seal the seams? Should a person paint a type of waterproofing to the poured concrete walls before starting a basement finishing project? What about applying the waterproofing to the floor? Thanks for your help.

I framed a 2x4 wall that runs perpendicular to the ceiling joists in my basement. Since walls in the basement are not load bearing walls, I used single (rather than double) top plate which was nailed directly to the parallel ceiling joists. The outer side of the framed wall is spaced from 1/2 inch to 1 inch from the cement wall surface. I'm thinking about a way to install fire blocks to meet Codes in Virginia where I live. So far, I cannot think of any good way. I think I can nail 2x4 pieces extending between adjacent vertical studs to the bottom surface of the top plate and extending outwardly into contact with the cement wall surface. But there are still a lot of small gaps formed between adjacent ends of adjacent 2x4 pieces, the outer surface of the associated stud and the cement wall surface. According to Codes, I can use wool insulation to block these gaps, but I cannot find any wool insulation in my area. Please help me if you can think of a way to do it. Thanks in advance.