Insulating Detached Garage with Shared Wall

[czechm8]

We just moved into a new place this winter and I'd like to finish the garage before next winter. It's a typical inner-city duplex (semi-detached) with a detached garage that shares a wall with our neighbours garage. The only garage wall that's insulated is the one shared with the neighbour, the other 3 walls and the ceiling are uninsulated. I'm in the process of insulating and finishing the rest and have 2 questions:

1) From what I can tell, the insulated shared wall (fiberglass bats) does not have a vapour barrier on either side (I can't see one). If I will be partially heating my side of the garage, and the neighbours is unheated, should I install vapour barrier on my side of the shared wall? Or is there any reason not to do this? I know it's always supposed to go on the warm side, but I only plan to temporarily & partially heat it (1-2 days a week when in use, and only to 5°C or so). It's Calgary so we're very dry here - summer there would be no issue without the vapour barrier, winter is the only question really. Anybody else have experience doing this same thing? I think there is a similar duplex down the street that is brand new, and was finished with a fully insulated and finished garage - I might check to see what that builder did as well (if I can track them down). Either way, it would be easy enough to do if so, the drywall isn't taped or mudded so I can easily take it down and reuse the pieces, but still more work than leaving as is.

2) We don't have NG in our garage, so I was just planning to use a 4.8 kW 240v construction heater and only heat it when I'm going to work out there, which would likely only be a couple times a week. This would only be to take the edge off the -20°C outside, ideally I would still wear a couple layers and only heat it to 2-5°C. Are there any potential problems with temporarily heating the space like this, and the resulting temperature swings? I know that if I go warmer, I could see condensation on tolls & metal surfaces as they take longer to warm up, which is why I only plan to partially heat it.

Thanks!

[CaberTosser]

Jackhammer up the floor, excavate down a few more inches, install 3" polystyrene, lay some oxygen barrier pex lines in the floor and then pour a new slab. Then trench insulated pex supply and return lines to your boiler and tie them in. And spray foam that dividing wall

[czechm8]

Originally Posted by CaberTosser

Jackhammer up the floor, excavate down a few more inches, install 3" polystyrene, lay some oxygen barrier pex lines in the floor and then pour a new slab. Then trench insulated pex supply and return lines to your boiler and tie them in. And spray foam that dividing wall

Haha , now you're talking my language! Start fresh, overbuild, and do it right the first time! If I did that though, I would also want to bring one of the walls out another 6', which may jeopardize the yard and my marriage

I think I know a guy down the street that could do the hydronic and boiler tie-in too...

[CaberTosser]

While you have that trench through the yard, might as well run sewer and water out there as well...... The breaking of the floor and slicing through the basement carpet, drywall and finishing trim is inconsequential compared to having running water in the garage