Anti-fracture or crack-isolation membranes. Our choices in this category run from simple one-step products and to liquid-applied formulations to sheet membranes (some of which require field-applied mastic, as well as others that have factory applied self-stick glue) and three-part systems. All of these product variations seem to perform satisfactorily.
Despite advice to the contrary, I’ve also seen continued use of building paper in on-grade installations. Doing so can lead to failures if moisture infiltrates the slab. Fortunately, the industry group that establishes related installation standards has finalized its work and submitted a revised set of proposed standards to the American National Standards Institute (ANSI) for acceptance. Unfortunately, in my opinion, the new rules include two standards -- one supposedly “standard” and one “premium.”