We were retained to investigate the cause of flooring distress to a retail center. The investigation included visible documentation of the observed distress, and moisture vapor transmission rate testing on the concrete slab. It was determined that the slab had an abnormally high vapor transmission rate that caused reversion of the adhesives, and the reverted adhesive was causing a loss of adhesion between the tile and substrate. The moisture also caused physical damage to the floor tile because concrete has a very high pH, which leached into the adhesive. We concluded that the floor was likely constructed without the required vapor barrier.