Good questions, and observations. The building has two car bays on the left, and the larger shop bay on the right.

None of it is complete yet, but the plan is...
The family room/kid-cave/guest suite is above the unheated car bays, where the dormers are.

It's a larger, nicer space overall. So, on this section the floor is spray foamed. Upstairs we spray-foamed the gable ends and the knee wall. We had planned to then insulate the ceiling with fiberglass or rock wool. We've since reconsidered and are going to also spray the (cathedral) ceilings, but I didn't want the foam directly against the steel roofing. We've applied this thin foam/sheeting called "fan-fold" on the underside of the ribbing, and now it can be foamed. This way the steel could eventually be replaced (thought that won't be in my lifetime).


There are many factors that played into this... the spray foam is great, but very expensive, and we just couldn't do it all. Fiberglass is, or was, comparatively cheap, but prone to rodents nesting in it, especially with all the entry point that corrugated steel present. My plan had been to do 3/4" v-groove across the rafters (4' O.C) and thus avoid strapping. Rock wool is heavier and has gotten pricey.
The shop bay has higher a ceiling, so less space above. The shop ceiling is insulated, but the upstairs area above it is cold storage.
There will be a lot of times when the shop will be heated, but the family room not, so I added the site built, insulated sliding doors. This is the first winter I've really ever had a heated shop. I've kept it at 45 degF all winter this year.
We didn't have a garage for years, but I swore when I built one it would be big enough to use, store, etc... and not have the cars parked in the yard because they don't fit.