Have been using both here for forty years and near as I can tell have had zero mold which can be an issue.
I have read this is a no-no ,,,here ,,,for many years. Going to go hang some rock here,,,Northern Nebraska where 20 to 30 below is common,,,, and 100 plus not unusual summer times.
There would be R-49 over the top of this,,,r-13 faced batts in ceiling rafter cavity. r-25 unfaced cross hatched with first across top of ceiling joists 90* to 13,,,,then r-11 on top of that same direction but split the seams.
have an odd corner on outside of the 25 where nothing else fits I am using shake and rake to fill void. roof is low slung and cant fit all clear to outside as I wish I could.
But back to question in hand,,,if you have introduced wetness/water I can see not drying well BUT do I continue doing what has always worked for 40 years or slit facing today??
AND related question,,,we have NO tuck tape anywhere around these parts,,,I have looked and looked. I have typar/tyvek tape and seems closest ...What is BEST TYPE OF TAPE TO FASTEN plastic to whatever???
Whatever you do, air seal religiously. You may have gotten by w/ the VB because of air leaks to dry things out; dunno. Many, many places are avoiding vapor barriers, instead going with serious air sealing and vapor RETARDER. I have a VB in my house, too, and no issues. Will one be in the new house? No way. Roll the dice there, I guess, but I will not use a VB. As for your insulation, are you aware that FG batts are the worst insulation on the market, and leaving them open in an attic is the worst way to use them? If you must use them, and you may have a good reason to do so, blow cellulose over them to "seal" them. Air blows through them like mad, robbing heat. Better yet, can you just blow in cellulose and forget all the fiddling w/ an inferior insulation? You'll have a far better job w/ cellulose. Either way, have fun. As for tape, duct tape is a poor choice. They make special tapes (I forget the names, but they are called "the red stuff" or "the blue stuff" around here) for polyethlyene sheeting, if you decide you just gotta have poly. Google will find the tape quickly.