After a tenant complained of carpet tiles coming undone, we were retained to figure out why. Our investigation included visible documentation of observed distress and moisture vapor transmission rate testing on the concrete slab. We determined that the slab had an abnormally high vapor transmission rate that caused reversion of the adhesives, resulting in loss of adhesion between the carpet tile and substrate. The moisture also caused physical damage to the carpet tile because concrete has a very high pH, and the leachate from moisture passing through the slab caused damage to the flooring. It was concluded that the carpet tile was apparently constructed without the required vapor barrier.