Got the sheathing up this morning, next will be the sturdi-floor plywood decking up top.
and from inside the room
To answer the questions - with the sheathing up, the studs are quite sturdy. After we get the flooring up (that 3/4" stuff is heavy) we'll see how it looks. DH can always add cats in between the studs if needed.
As to insulating and heating the entire building, that would not be practice for the intended use. Our place once was part of a much larger farm, and we got the homestead and outbuildings plus 40 acres. We've been converting the buildings over to ones more usable to us. The old grainery is now the chicken coop, and the pig shed got converted to boat storage. One of the storage sheds will be converted to my green house (some day!!!) and we're dividing the shop into garage space and a heated work room.
The shop is not what DH would call "quality built" and would take a ton of work to tighten it up to make it heatable, not counting insulation and other materials. However, the cement slab is in very good condition. The bad part is there is no vapor barrier underneath, so it weeps. But when you buy existing buildings, you get what you get.
DH and I enjoy woodworking, so we wanted a room we could keep the dirt and dust out of (that takes some work here in dry, windy SD). Some day, I may have an attached garage, but for now the shop is where I keep my car. It's not so bad in the summer, but I hate having to clean snow and ice off the car most mornings in the winter.
I'd like have to kill someone if I had a freshly varnished piece of furniture in the room and then have someone hit the garage door opener and have dust blow through the place. We also hope to seal the room up enough to cut down on the hordes of flies that get in there. They all die in the winter - so I'm still sweeping dead flies off the floor.
And the room is also big enough for DH to do mechanic work in the winter, when he does not want to be out in -10F temps (not to mention wind chill).
We had a really nice workshop in WI (that we built) DH would occasionally heat the place up, and it rarely even dropped below freezing inside. I agree, you don't want it too hot, about 50 is good in the winter.
We rationalize the cost of this in that once it is done, we'll be able to make the cabinets for the kitchen and bathroom. We're using the pine flooring we pulled out of the house (really old, tight grain, no knots).