poly under thin radiant slabs?

[Deleted User]

For the past twenty years I have installed polyethylene sheeting under the concrete in radiant slab heating installations that I have facilitated. For the first time I have been instructed by both the builder and plumbing inspector that the home that I am currently installing does not require poly under the thin slabs on the main and upper floors. The grade slab received poly as usual. Your comments please.

hot_rod

thin concrete slabs?

should have a bond breaker or slip sheet over a wood subfloor. It also keeps the wood from drawing the "waters of convenience" from the mix., which leads to cracking and too quick of a set. At least that is what the concrete experts at RPA seminars have always told us.

Now with gyp products you want to spray a bonding agent, looks and smells like Elmers glue.

hr