[Greenbuilding] flooring underlayment

[Bruce Donelson]

My favorite underlayment is a 1/4" birch plywood with no voids in the
interior layers. I get it from flooring supply houses. It costs about $25
per 4x8 sheet.

Bruce Donelson

I was curious to know what product is preferred for flooring underlayment.
The building is designed for 3" concrete floors.  But some of the floors
will be wood, cork, or marmoleum.  I was going to put in sleepers (2x4's) to
build the floor up even with the concrete, then an underlayment, then the
finished product.   What should I use for the underlayment?