Just to confirm, Tyvek is NOT a vapor barrier! It is a house wrap that stops air infiltration but allows water vapor to pass through. There are a lot of reasons for this, but that is a whole other story. There is no way that tyvek is what you want. Besides it is expensive. I don't have any direct experience with the plastic on the ground (floor) but I have seen it enough on this board so it probably is the right thing. All of the other comments make sense that Jim and Jay J submitted. Get rid of the water. Pump it out if you need to. If it is still humid then get a good dehumidifyer. Water is death to wood.