Michael, The drywaller is indifferent about whether I put up the plastic or not. this is my call, and while I've tried to find a definitive answer, it seems one does not exist. Your points are good and having no moisture source (per se) in the shop is why I was searching for the pros/cons. Right now the place is to stay with the VB paint, by the time I get to the purchase point that may change. What I have learned that no matter what I choose to do, there will those who agree and those who disagree....split about 50/50; hence the dilemma. But the plastic is out, it will be the VB paint or nothing.

All this time I thought your barrier was to keep moisture out of the shop. Shows what I know.

I don't understand this part of construction all that well, but one of the more interesting columns published in the air conditioning journal is "Building Sciences", which attempts to fill our AC heads with an understanding of moisture control.  Every time the guy mentions moisture barriers, it comes down to "no plastic or other impervious barrier".  Turns out, some moisture migration through the structure is desired, so you use materials that allow slow movement, such as OSB.  It rejects water, but will allow moisture.  Here is their website, with a lot of articles available on the topic:  https://buildingscience.com/document-search?term=&field_doc_topic_tid=All&type[]=5

There are a lot of old homes out there built without vapor barriers and still standing.

Housing went through a period during the late 80's and 90's of being built too tight where there was no moisture escaping from cooking odors. from aresol cans from other sources, and they also had mold problems.

Herb

On 6/13/2017 at 5:27 AM, Fred W. Hargis Jr said:

Michael, The drywaller is indifferent about whether I put up the plastic or not. this is my call, and while I've tried to find a definitive answer, it seems one does not exist. Your points are good and having no moisture source (per se) in the shop is why I was searching for the pros/cons. Right now the place is to stay with the VB paint, by the time I get to the purchase point that may change. What I have learned that no matter what I choose to do, there will those who agree and those who disagree....split about 50/50; hence the dilemma. But the plastic is out, it will be the VB paint or nothing.

 

 

How is progress on the shop Fred?  I had a thought on the moisture barrier the other day. You might consider putting the insulation ,at least part of the required thickness in before the drywall, or get foil roll moisture barrier and staple it to the joist before drywall, then in either case blow more as needed after drywall.

Just saying,

Herb

I agree Herb, that was something I had considered...putting in some Kraft faced R13 glass just for the vapor barrier, then blowing loose fill in over it to get the R30 or so that i want. In the end, I just got lazy.....I've decided to just go with vapor barrier paint on the ceiling. But the drywallers are supposed to be here the last 1/2 of this month. Here's hoping they do as they say (contractors around me are known to not show up at all). this guy was recommended by a couple of builders so I'm hoping for the best. This wait is killing me....I'm eager to get on with the rest of the finishing work.

Man, if this keeps up, we won't be able to have a shop-warming picnic, it's going to have to be around the fire.

 

Bet you're getting anxious to  be making sawdust.

I am, besides that it's getting to be a real battle to keep rust off the big tools stored in the garage.