"Dave C" wrote in message
...
This is a thin layer of lightweight concrete on second floor of a light
industrial building. No moisture will be coming up through the concrete
unless sea level comes up by about 100 feet.

Well, youjust never know. If it come sup 99' 11" you want protection. If
it comes up 100' 2", it will not matter anyway.


Installers didn't mention a
moisture barrier; they seem to be pretty careful company. Glue directly
on
the lightweight concrete.

Most installations on concrete are a slab on the ground, but your case is
different, of course. It will be interesting to see if Mannington has
anything to say about it. As I said, the glue seal in the t&g is good in my
case, but in yours, they may not have to glue the joint since it is glued to
the floor. . There is a little potential for water to soak in that way.
Ed

http://pages.cthome.net/edhome