I have mold/mildew under the flooring in my bathroom. I don't know what to do for a new floor, to prevent staining. There is some sort of water coming up in my bathroom, I think from a slight crack in the slab. Could I just lay another layer of sheet vinyl over this to keep the stain from coming through the top layer? I've heard of that being done here in the south. We have so much moisture! I have 3 layers of flooring in the kitchen one laid over the other and 2 in one of my bathrooms. This is what many floor people have told me was one way to solve the problem. Is it? If not, what type of flooring would take the moisture without turning colors from mold under the flooring?
Sounds like you have a time consuming and probably expensive job ahead. You may even have a water leak that could be causing your water bill to be higher than normal.
The main point that I would like to make is that where there is water/moisture there is most likely mold (maybe even in the "fixed" bathroom or kitchen) and this is a big health problem. I live in Florida and I know that I am constantly fighting mold in many inside places. Have you checked your closets lately? Sometimes the baseboards will have mildew/mold and even clothes can be damp and leather will mildew.
I do not believe any Florida home should be without at least one dehumidifier. i keep a 40 watt light bulb burning in one closet 24 hours and my house is considered "over" insulated.
It would be nice if it were a simple job but most of us have run into similar problems at one time or other. I hope the leak is easily found and you can get your life back to normal.
I'm glad you plan to buy a dehumidifier as I really believe you will be shocked at the amount of moisture collected even in 2 or 3 hours. It would be best to do a good search of different models of dehumidifiers as there is a big, big difference in price and I have found (over time) that it does not take an expensive model to do the job.
You need to fix the source of the leak, or you will have floor damage, wood rot, and bugs.
Agree with Pariser-the damp is coming from pipes, the ground etc., and the locus of the water must be fixed or the problem will only continue and most probably worsen. If you own the house, try to find a way to fix the problem. If renting, the owner has the responsibility to address the condition.