Hi, Curious. Not the answer you want to hear, but "it depends". We install wood flooring in the North East. We have tremendous problems with climate here. Humid summers, cold dry winters.
And that doesn't even get into ground conditions, which are the biggest headache. We have an entire area of town that is all slab construction, no vapor retarders, and so much moisture coming through the concrete that attempting a glued down wood floor is not something we'll do. Had one client tell me with glee that "so and so" put down a wood floor and there were "no problems". That was for the first few months. Then spring came and . . .
Now he wants help suing the people who put the floor in. How about suing yourself? You were told we couldn't put wood on that slab and you did it anyway. That sure sounds like negligence.
The issue is not just one of ground-water levels. In fact, it is rarely ground-water that causes the problems. It is vapor. (Humidity in the ground, if you will). New England is fun.
There are numerous vapor retarders that can be used, and each of them will work up to a point. Read and understand what the limits are. I prefer avoiding extreme moisture situations. For clients that really want it and know the risks, floating is our next preferred method. We'll use a vapor barrier that creates a "bowl" under the wood, pushing excess vapor to the edges.
Common question we are asked: Can't you just glue that vapor barrier down and then glue the wood to that? No. If moisture is an issue, then vapor pressure will pop the glue (if it's strong enough) and you have a floating floor anyway. But a floating floor with problems now.
But aren't there glues that will withstand higher vapor pressures? Yes. But once you cover it with a barrier, that vapor pressure will just build up and build up. You can have pockets of moisture. When it builds enough pressure, it will burst through the vapor retarder. Or pop the glue. And that bubble of "water" under the retarder? It's also quite caustic. Very alkaline. Pop it, and you may find a high pressure stream of alkaline material can take out an eye.
Had a town with a gym floor that was blown. They want help. Moisture is the problem, and the original contractor is gone, gone, gone. You tell them what can and can not be done. They think that replacing the wood floor with a rubber floor is the solution. Wrong. But they don't want to hear it. More money wasted. (We were too expensive, you see). Ahhhh. So frustrating.
