Interior Vapor Barrier

[Yukon1962]

My new shop/garage is split into three 'rooms':

1. Shop
2. Utility Room
3. Garage

The building has in-floor heating, and is divided into two areas to control.

The Shop and Utility Room are on the same circuit and I expect to heat to 50-60F range. Originally I wasn't planning on heating the garage area, but now I've decided to at least keep it above freezing.

I've put Rockwool sound barrier between the shop and utility room since I plan to put the standup air compressorbin the utility room. Between the these rooms and the garage I plan on 2x4 R15 Rockwool.

My question is whether or not I need vapour barrier between the two areas. I assume so, but I just want to make sure. The temp difference is not that great. It's also dry here in Winnipeg in the winter anyway and Rockwool is more resistant to moisture than fiberglass.

Cathedral ceiling in Shop will be spray foam, and garage ceiling will be blow in cellulose probably.

Thoughts?

 

[The Cobbler]

There's ongoing discussions if vapour barrier is even needed in a garage setting.
in any event, just vapour barrier on the last heated wall before the outside.

 

[purediesel]

So I am sort of doing the same thing. I have a shop that will be split down the middle and one side will be cold storage but will be heated at sometime, while the other half is a fully functional shop that is getting heated hopefully this year. I am putting up a partition wall without vapor barrier, and my reasoning for this is that it will dry outward to the rest of the cold storage area. For this to work I will only finish the shop side of the wall until I get the cold storage finished and sealed up. I don't know your building but my cold storage is just a floor and walls for now.