Q: One visitor asked, "Should a water vapor barrier be put down if the hardwood flooring is to be installed over OSB over a full unfinished basement? How should the flooring be laid? Parallel or perpendicular to the floor joists? Why?"

A: I will give my opinion here. When one talks about installing hardwood in a basement, it can be a scarry thing. Moisture is an enemy of hardwood. My first point is this: I know of no solid hardwood flooring manufacturer who will warranty solid wood installed below grade. You have not told me what you are installing, so I want you to be aware of this. There are laminates on the market designed to be better adapted to this environment. By OSB, do you mean chip board? I would never install a nail down product to chip board. An easy test for moisture from a basement floor would be to tape plastic squares to various areas of the concrete and left for a day or so to see if condensation develops on the plastic. Even if it doesn't, a vapor barrier is not a bad idea. One thing I would recommend in the construction of the subfloor is this: Build it in such a way that air can flow up and down between the joists. You may wish to include a couple or several vents in the floor surface to accommodate this. I say this because, if you ever get moisture under the subfloor, it can linger a long time without proper venting. More often than not, it is best to run your finished floor across the floor joists, since this will increase structural stability, the floor joists bearing most of the weight of the finished floor, rather than the plywood or OSB subfloor.