Concrete effluence coming up through tile grout

[rosecan]

Have 360 sf sunken living room located in the center of the house, no exterior walls....concrete slab 4 inches below main entrance, 4 inches above outdoor screened in Florida room. All floors are porcelain/ceramic tiled. Two years ago installed porcelain tile that looks like wood in living room, and porcelain tile on entry level. Florida room has ceramic tile installed over 20 years ago. Living room was carpeted for 20 years; never saw any evidence of moisture until we replaced it.

Problem...white effluence coming up through the grout from concrete slab., only in living room; not in entry or Florida room. Have been researching solution to this for 2 years...contacted experts in tile, concrete, grout, plumbers, geologists, hydrologists..you name it, I've talked to them. General consensus is the water barrier below the slab is comprised thus allowing moisture to ooze up through the concrete. Hydrostatic pressure?
No firm advice on what to do.

So, we have decided to remove the tile in the living room, treat the concrete with a waterproof substance and replace it with carpet thus allowing it to evaporate as it probably was doing before when it was carpeted before.

What would be the best waterproofing material to use?
Or, can anyone advise how to fix this without removing the tile?
Tried to attach some photos..

Removing the tile in 4 days...

Thanks,
Rosemarie

 

[havasu]

Is this floor below grade, where moisture is a continual problem?

 

[rosecan]

No, all floors are on concrete slab on top of soil. The water table is high in Florida so building below grade is not possible. I really think the vapor barrier under the slab is broken, dissolved or maybe not ever put there. House is 30 years old. We think we always had this problem but didn't notice it because for the first 20 years it evaporated through the carpet. That's why we want to put carpet back down. Can't seem to find anyway to fix the problem without removing the tile. Do you know of anyway we can do that? If not, can you recommend a waterproofing/or mildew proofing for the concrete that we can use before we install the carpet?