In a condo, and just discovered that the floor is actually gyp-crete, presumably over wood. Is a moisture bnarrier necesary? This is above grade.
The answer is :
- It depends
Above grade doesn't mean above ground, necessarily.
If you are referring to concrete that rises out of the ground - then yes, you should put down a moisture barrier. Concrete is porous and moisture will (slowly) permeate the concrete if there's enough moisture around.
However, if the concrete is suspended - a concrete floor above ground with air below it - then no you won't need a moisture barrier.
It further depends on the kind of floor you're installing. Greebo is right about the barrier, but a "just in case" application if you're not sure might still be redundant. Vinyl flooring will be far less adversely affected by water than, say, hardwood. You mightn't need a moisture barrier, but if you're going with hardwood, you'll need to be nailing the floor down. That will mean you need a subfloor of some sort, since gypcrete doesn't hold nails well at all.