I've looked at hundreds of postings and cannot find anyone who asked this. I'm putting a new floor in a room built over an existing carport concrete slab. (Termites ate the whole thing, walls and all!) The new joists are approx 8" above the slab. Before insulating I feel a vapor barrier is needed between the concrete and the joists since the grade of the property allows water to run under the floor. I've installed a sump pump to remove the water. Any ideas?