I bought laminate floor from Costco. The kind that has thin insulated padding underneath. My contractor recommended to put plastic sheet over the concrete and lay the laminate floor over the sheet directly. He said the floor will easily fell apart if we use the underlayment the guy from home depot recommended (the soft grey material about 1/4" thick.) I agreed and he just finished laying the floor today. It turns out the floor creaks all over! Is this normal? When I stepped on a few spots, I can actually feel a gap between the floor and the concrete.
I would appreciate it if some one here could recommend how to correct this problem? Would it help if we use the underlayment (which mean we will have to re-do the floor...).
Thank you in advance. pax