While working on my basement, I've been thinking about the challenge of putting a vapor barrier on insulation between the ceiling joists where they sit on the foundation wall. Most houses I've seen have batts jammed into those cavities but no vapor barrier. A few have 6 mil plastic that must have taken days to meticulously cut and staple. Here's a solution I've come up with. I welcome your feedback. I cut a batt to fill the cavity. I then made an "insulation pillow" by putting it into two small white plastic kitchen garbage bags. I rolled the bag flap closed and sealed it with red Tuck Tape. The pillows sit nicely in the cavities, resting on the top of the conventional stud wall I built for the wall batts. I know the garbage bags are well below the 6 mil standard, but I figure this standard was aimed at preventing the vapor barrier from getting punctured -- an unlikely occurrence high up on an unfinished wall. For larger areas, I made the pillow by wrapping 6 mil around the cut batt and sealing it with red Tuck Tape. Again, any feedback would be appreciated. Thanks

I have very liitle loos insulation under the planks in my attic, if i were to lay rolls of insultation over existing floor would this work, or would i need to pull the floor up and lay insulation underneath the floor boards. thanks JC