Abstract: The invention provides a method for making a concrete floor slab using sub-grade waterproofing in a manner that favors the use of water-based adhesives for affixing floor covering materials. The method comprises casting a hydratable cementitious composition onto a flooring membrane, the composition having a shrinkage reduction admixture and a water:cementitious binder ratio sufficiently low that substantially all of the water moisture is retained in the hydration reaction, and achieving a fully adhered bond with the flooring membrane.