Hard to tell without knowing what glue he used or what the slab conditions are. They make adhesives today guaranteed to block moisture from coming up and damaging the wood. If he used one of those and applied it correctly you might not have anything to worry about. They also make moisture blocking coating that are applied first, then the adhesive. How long has it been in place? Is there anything about the wood that looks questionable? Cupping or warping? Are you sure it's solid and not engineered? Good engineered floors have a pretty thick top layer. Engineered wood floors may only expand 10% as much of solid hardwood, lessening your concerns. Is the slab on grade? How old is the home? It's possible if the home is newer there may be a vapor barrier under the slab. Is the home on top of a hill or does rainwater flow down towards the home, like being near the bottom of a hill. Where is the home located?

Thanks for the reply. I think it?s been in place for a couple of years. It?s solid and not engineered. The wood looks fine, I didn?t see any signs of any issues. The slab is on grade and the house was built in 2005. Water will not flow towards the house. We are in central NC. Thanks!!