Solid Hardwood, Engineered and Laminate Flooring - vapor barrier

I am installing a laminate floor and currently I have a vinyl/linoleum floor attached to a gypcrete subfloor. I live in a second floor condo in Denver, Colorado. So, do I really need a 6-mil vapor barrier or will the vinyl/linoleam floor act as a vapor barrier. Also, there is a part of the floor that I will be replacing with laminate that is carpet. I pulled up the carpet, so now I have one part of my floor that is vinyl/linoleam and another part that is just gypcrete. Anyways, can just layout a linoleum sheet (without glueing it down) and use this as a vapor barrier or do I have to use 6-mil plastic. Will it matter that it is not glued to the floor? This way I figure I will have an even floor and the vinyl/linoleam shouldn't make the crumpling noise that the 6-mil plastic will make.

I would like to know this as well. My floor will have a portion of just vinyl and another portion wood.

Use the vinyl as a vapour barrier. When you have a gypcrete or lightweight concrete floor, it's considered an above grade floor since the concrete is poured on a wooden sub floor.

Where the confusion lies is with solid concrete structures, that type of floor requires a vapour barrier since concrete will wick in moisture.