Engineered Hardwood on sleepers on slab?
Installing 1/2″ engineered white oak flooring on plywood that is attached to 4×4 sleepers on a concrete slab. Room is a converted garage space that was raised with sleepers. My question is should any additional vapor barrier be installed? The slab in the 1960s house has the original vapor barrier below it. It is effectively an unventilated ( very shallow ) crawl space between the redwood sleepers. Plan is to staple/nail the planks to the plywood subfloor with a 1/4″ cork layer sandwiched between. I assume some moisture will need to escape through the flooring and a vapor barrier on top of the plywood will trap moisture in the subfloor/framing. I realize this assembly isn’t ideal but wondering what the best installation would be?