[rnln]

umm... how do I know if my floor has moisture or not? It had the old laminate floor. When I pulled them off, there was a layer of very thin foam. The concrete has the black stuff like asphalt. While working on repairing drywall and such, I made the floor really dirty now. I know for sure I can't clean that black stuff any more. What is the best way of removing that black asphalt like thing? Paint thinner?

RWebb,
there are lot of stores and I already visit several. I ask here because I know there are many people here do things much better than the usual installer out there. All stores are telling me to simply glue wood down to concrete, and float technique on laminate.