I just attended a Junkers hardwood seminar. They will stand behind this product a 1/2 " solid, when glued direct using Bostik, glue and the MVP. The thought sends chills down my spine. There is no long term precedent, to judge this by. But yet, there are those on this board that use this system to glue down the plywood, on concrete, that they nail 3/4 inch solid to. Why would that work, and not this?

Let's put it this way. Solid on-grade has never been recommended. If a manufacturer/s want to recommend it, who's gonna stop them. If they say they will "stand behind it", what does that mean? Stand behind you and ream you? I don't trust too many manufacturers claims about "this and that" if it is outside of industry standards. They usually duck and cover when the s*** hits the fan. I've seen it way too many times. Can it be done? Yeh, you can do anything you want. The question really is, "Should it be done?" I'll bet you five that in their tiny, little print escape clause somewhere, there's an exclusion that every "failed" job will have so they can say," Aha, installer error!" Ask the guys that do inspections for hardwood floor manufacturers the percent of claims the manufacterers actually replace or refund. Very low. IMO, that recommendation is just a sales tool to sell more wood.
BTW, plywood is ENGINEERED WOOD: Junckers is solid. Apples and oranges again.

Most of the claims guys I have seen act like they have been trained to debunk your claim. I have had them say they wouldnt replace jack because there warrenty clearly states that the homeowner/installer makes the final judgement to install any given plank and by commiting the installation it constitutes aceptance. Which imo just makes an easy out for the manufacture to hide behind.

[quote=DO NOT PUT A SOLID OVER CONCRETE!!![/quote]

Unless you aint skeered