Ereil writes from somewhere in the world: "I removed the ceiling and previous insulation in my garage. Now I have the above floor and joists. I've seen batt insulation in between the joists with a vapour barrier (plastic sheet) on the lower side of the joists. But the vapor barrier should be on the warm side. Would it be recommended to put batt insulation with Kraft paper installed on flooring side?"

Answer: If the garage is heated you do not need a vapor barrier. If the garage is not heated you can install a vapor barrier on underside of subfloor sheathing or paint it with an oil-based paint, then install batt insulation between joists so vapor barrier (poly or paint) is on the warm-in-winter side. Because your note did not include your postal code I don't know where you live, but be advised that Owens Corning does not sell insulation with a Kraft-paper facing in Canada.