Now that I have laid my engineered wood floor throughout the den, kitchen, foyer and hallway... I'm now beginning to wonder if I did the right thing. My question is, "Should I have not reused the foam underlayment (a material called hush step) that was already there from a previous laminate floor install?” I even purchased and laid down additional square footage of this material for the areas that were not previously covered in order to have a uniform thickness and levelness. I reasoned at the time that if this material was good enough for a laminate install, then it should be sufficient for an engineered wood install. Well I'm now beginning to wonder if this material may be to thick and may have too much give for an engineered wood install. The floor feels wonderful underneath your feet as it has some give but occasionally I hear some popping sounds so I'm wondering if the floor is flexing too much and the sounds may be joint/seam movement. And yes I did remove the laminate. So what we have now is the floating tongue and groove engineered wood, and underneath that is the aforementioned hush step foam underlayment pad, and underneath the foam is a layer of plastic (as a vapor barrier), which in turn is over a concrete slab. Any insight would be greatly appreciated and may or may not ease my mind. At this point I just want to make it right.