1. I live on the 14th floor of a 60 year old building. Would I need a moisture barrier?2. I want to glue hardwood to cork underlayment and float the cork underlayment over the concrete. Is this possible or advisable?
Most engineered flooring doesn't require a glue down, if you do want to glue it down, you'll have to do it directly to the concrete. You can a concrete sealer as a vapor barrier. I've installed most of these systems using a foam vapor barrier with no fastening, as a floating floor. Good Luck!
If your apartment is over another living space and not something like a mechanical or pool floor (the latter unlikely so high up), then you will not need a separate vapor-barrier. As to the latter question, if the floor requires the substrate to have structural integrity, it will not be a good idea to float the cork as it has very little lateral structural integrity - sideways forces may cause it to fail. If you want to float the floor, you might consider a locking-style material - one designed for exactly that sort of application.
I would use cork underlayment which works really good for sound deading purposes. If you go with the cork underlayment then you need to go with a floating floor. Locking hardwoods provide this option as well as using a regular engineered tongue and groove hardwood. If you go with the tongue and groove engineered you'll need to make sure it is at least 4 wide and use must glue the boards together with tongue and grove adhesive. So you float the floors but they are glued together. This option or going with an engineered lockign hardwood are your best options.
No moisture barrier is needed since your a little bit above grade. What you want to do in question # 2 won t work sorry . Your best off just gluing the engineered flooring directly to the concrete. If your looking for a sound deadening procedure, get a floating engineered wood flooring and up grade the underlayment to a quiet walk or what ever they ll call it for that particular product. Any questions you can e mail me through my avatar.. GL
