We have a mobile home and live in a very humid area. The insulation under our home was sagging and ripped beyond repair. We removed it all and replaced it with the normal rolled insulation you would use on homes. We tucked it in between the floor joists with the paper side up against the floor. I've noticed our floor starting to buckle (our air conditioning truck lines are all totally insulated). Would stapeling some type of vapor barrier up against the joists help? If so, what kind of vapor barrier. Would plastic sheeting work?