I have about 160 sq. ft. of the Shaw glueless laminate to install on a
bare concrete slab. I also got the 2-in-1 underlayment that they sell
to prevent moisture and heat loss (I think that is its function).
Question is I had someone make a strong suggestion to me that before
installing the laminate, to install 1/4" (5.2 millimeter) exterior
grade plywood over the concrete. This is supposed to soak up some of
the variation in the floor (not much if any as far as I can tell) and
help prevent moisture from affecting the laminate? Said to use liquid
nails or some such adhesive to hold it down to the concrete.
But reading the manufacturer's instructions it says to not use the
2-in-1 underlayment over organic surfaces (i.e., wood subfloor?), and
if there is any "wood flooring" on concrete to remove it before
installing the laminate. Not sure if that statement was meant to
include "wood subflooring" (which is not really "wood flooring", like
I am going to call Shaw for clarification but just wanted to know if
anyone had any practical experience they could share.