I have completed the framing of my riser and put it over 4 mil plastic as a vapor barrier. As the riser is 6" and I am using R19, the insulation would be touching the concrete floor directly without it.

I have been having second thoughts...should I rip it out so I don't trap mositure and create a mold issue? I ended up removing the plastic vapor barrier in my walls but I had a 1" airspace. The insultation was not in direct contact with the concrete walls. I do not have a moisture problem in my basement...if I tape plastic to the floor and leave it, I do not get any moisture. I have noticed most people use the vapor barrier under their risers on this forum. If I were to leave out the vapor barrier would the vapor eventually rise through the plywood and carpet on top? I don't think so. Is it better to trap vapors under the plastic or in the riser itself. Hopefully...I don't get either since I have never had a problem!

What do you think?

Thanks,
Dave

http://i397.photobucket.com/albums/pp55/dbaiano/Cnv0563.jpg

Come to think of it...when you install a wood floor, don't you put in a vapor barrier under the floor. Doesn't that create the same issue???

I put 30lb roofing felt under mine, as it is code here. I did not use PT lumber either

1) A floating wood floor laminate typically has a vapor barrier installed underneath.

2) A ceramic tile floor is kind of like a vapor barrier,

3) Many people seal there basement floors with a paint or penetrating sealer that becomes a vapor barrier

4) Many homes have carpet installed over a pad with a vapor barrier,

5) A glued down linoleum floor is a vapor barrier

6) Many homes have their concrete floor poured over a vapor barrier.

I just don't understand the phobia that has been expressed in other threads about a little riser or stage sitting on top of a vapor barrier.

My personal feeling is if you have enough moisture in your floor for that to be a problem you really shouldn't be building in the basement until your moisture problem is remedied or you build a suitable sub floor to keep everything up off the concrete.

I agree 100% with everything Bigs has mentioned above. First and foremost if you have a moisture problem deal with it first or install something like dri-core.

Since I know I do not have a problem (with moisture that is, ha,ha) I am not going to worry about it. It is so easy to second guess everything you do before you are going to make it final by closing it up.

Thanks,
Dave

I used the 30# roofing felt also, but I also fused PT lumber to white lumber although I still used U-boats. It is most likely overkill but didn't want to take any chances or violate code.

Thanks for your reply tradewinds.

In my area, it is code to use P.T. anywhere wood touches concrete. Not sure if the vapor barrier would have changed that...I didn't do it to try to meet code. I just did not want the R19 to directly touch the concrete.