The subject of vapor barriers or retarders beneath concrete slabs on grade has long been controversial. Some justifiably argue that slabs placed in direct contact with a vapor barrier or retarder are more susceptible to curling and other slab problems than those cast on a granular base. They consider a vapor barrier or retarder a downright nuisance.
Others have experienced or witnessed the devastating effect of moisture on modern floor coverings, adhesives, coatings, and a building's environment. They will justifiably argue that a vapor barrier or retarder beneath the slab can be an absolute necessity.