I just finished installation of Harmonics laminate floors (actually, "Quick Step", resold by Harmonics at Costco). In a couple of places the floor surface was pretty bad, and the installer had to add an additional layer of underlament. These places now feel like slightly "floating". I was wondering, how badly this will affect their durability ?
Don't know but you should be concerned. If it does adversely affect durability, it certainly won't be covered by the manufacturer's guarantee. Adding another layer in places is not approved, in fact, the instructions say not to overlap the underlayment. The floor needs to be out of level no more than 1/8" in 2 feet. The way to achieve that if the floor doesn't meet that specification is to use a cement type of floor leveler.
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