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 ?

Ikon wrote:
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.