cant deciding what to do about sleeper floor on slab
I have a 2 story house on slab-on-grade foundation. First floor is garage, second floor is main living space. I recently purchased this house and am remodeling. Previous owners built living space on half of the downstairs garage. There is no concrete treatment or cover at all on the slab. They put pressure treated lumber on its flat side as girders about 3ft apart, then 2x4 joists shimmed to level at 16"OC, and 3/4" OSB subfloor.
Since I purchased the house, I've been doing a LOT of research on properly creating living space on concrete and all the moisture problems: how to seal the concrete, the vapor membrane products that are available, the types of flooring the avoid due to risk of moisture damage, etc.
But at this point, for me to do it properly will require me to basically rip out and re-do the entire lower floor. The interior walls (non load bearing) were build on top of the sleeper floor, so that's gonna go too. Con: it will add a tremendous amount of time and money to the project. Pro: it'll be done right, and it'll give me an extra inches of height in the rooms where it is now just barely enough to meet the 7'6" requirement.
As it is, I do not see any mold/mildew, but there definitely is dampness on the concrete. I suppose if I choose the right flooring (breathable) and keep the rooms ventilated, I can get away with it. If it was a basement below grade, I wouldn't even consider it, but on grade, I dont know, maybe i can get away with it?
So I can't decide what to do? What would you guys do?