Concrete – Basement concrete leveling issue for click lock hardwood flooring installation

There is no reason to glue down engineered hardwood floor to an underlayment. This is just for initial aesthetics. The glue will NEVER last (in a residential setting). The only thing the glue will do is give you fits and make your install seem tighter. Within weeks or months the glue will come loose and you will have a floating floor.

Nothing wrong with a floating floor. But the fact is you should be gluing the pieces together, not under them. The big boxes sell the generic engineered wood flooring glue. Buy that and glue your pieces together, not under them. The only time I have seen gluing to the floor to be an option is thin flooring onto concrete for commercial purposes. The only thing I would glue down in someone home is vinyl sheets/squares.

I have had 3/4" hardwood floors placed on Dricore on 2 different jobs. One below grade with a foundation drain system the company I worked for installed. Top of the line, no holds barred water control system. The floor went down a is still performing beautifully. 1 1/2" staples were used so they did not go through the plywood so far to poke holes in the dimple mat. This was tested on a piece to insure this would not happen before the flooring was laid. The other floor was done with wide plank flooring, 5 years ago still working great to this day too. So you would not be going wrong if you went with Dricore. I placed this on the concrete without a vapor barrier in either case, but the floor was sealed.

You may need to check what the staples will do with your thinner engineered flooring. Also, you MAY be able to direct glue the flooring to the concrete slab since it is above grade. Since it is a newer home there should be a below slab vapor barrier. Two good conditions to have, so you don't get moisture rising through the slab.