One More Flooring Question (Vabor Barrier)

Alright, thanks to all of you that have responded to my posts so far I've gotten a lot of helpful tips and advice. I went to LL today and they actually told me that it was OK to use this liquid moisture barrier and the MVP glue to glue down 3/4 in. I told them they were full of crap and no installer would every do this. So I've decided to go with a subfloor.
When I ripped up the old flooring I found that the concrete wasn't tension concrete so I can nail the wood into the concrete to create the subfloor! woohoo. I had the guy put down 6mil vapor barrier then cabinet grade 3/4 in plywood on top. When he put the vapor barrier down he didn't overlap all of the seams he just taped them together. I need to have him overlap all of the seams right ? Sorry for all of these rediculous questions, I feel that I know more about flooring know then the guy who's installing them! This guy also thought he could buy a moisture meter at home depot for 20 bucks....its amazing how little you have to know to be a liscence and bonded contracter.
Does anyone have any experience with the felt pad that has a plastic moisture barrier on top of it ? LL told me i could use this instead of using the moisture barrier beaneath the subfloor. I decided to go with both so the layers will go.
cement moisture barrier plywood felt moisture barrier wood
Thanks Again!
J.
P.S. I'll post pictures of the finished project (if anyone cares). Should look nice with the new base boards too.
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Leave 1/8" gaps between plywood sheets.
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Yao -
Yeah i have gaps between the plywood but does the moisture barrier need over lap ?
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JTurner wrote:

Yes, the vapor barrier seams need to overlap by about 6 inches and you should then seal the seams with builders (tyvek) tape. It takes care of moisture and soil gases that can migrate upwards. M.
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For moisture it it must read something like 15%, im not sure on the exact % you must have, you need to research that before you install. Humidity is not the same as wood moisture. I would test the concrete also, one meter will do both, that will let you know what treatment is needed. A 20$ meter, maybe, On E bay they are alot more than 20. I have a Delmhorst or delmhurst? 250$
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I'm no expert, but I'm under the impression that two moisture barriers is a bad idea, because any moisture that ever makes it in between them will never dissipate. Of course, since you are nailing the plywood to the concrete, you'll be puncturing the lower moisture barrier alot.
Wayne
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