A couple years ago I laid some water proof vinyl plank laminate over top of some tile floor in the kitchen and dining area and over parquet flooring in the living room of a condo rental I had. It recently buckled up and when then tenant was gone for a couple weeks. She said before she left she noticed it feeling spongy in areas. So I removed the laminate I found the parquet buckling underneath. When I installed the laminate, the parquet was in excellent shape and was very firmly glued to the concrete floor. I was told be the flooring store that the glue would act as a moisture barrier and I could lay the laminate directly over the parquet. The flooring over the tile had no issues. I'm getting conflicting advice. Some say the floor had to get wet somehow as the glue should act as the barrier. However, I found no signs of water much less a water leak. Others say The laminate buckled because the wood could not breathe. At first I was convinced that there was a water leak that my tenant failed to tell me about but now I feel as though this laminate should not have been put over top of parquet. Any thoughts?