New Workshop

I'm building a 16'x16' workshop and planning on using metal panels for the roof. I'm planning on heating and cooling it sometime down the road, and want to make sure I won't have condensation problems. The roof will be a 6/12 pitch spanning 16 feet. From my research my plan is (from inside out) ceiling, vapor barrier, insulation, vented attic (soffit, ridge, and gable vents), roof deck, underlayment, metal roofing.
Does that sound right? This isn't a living space, so is there an easier/cheaper way of doing this? Do I need decking, or can I lay out some sort of sheeting between the rafters and roof?

Sounds like a well thought out plan. Insulation and vapor barrier aren't that expensive so there aren't many ways to thin the budget more than that. You don't want the vapor even getting into the attic so this would be minimum spec.

Solid sheathing on the roof is very much preferred here and even in applications where the roof is vented properly and everything else is done right, you can still get condensation on an open roof deck as a result of moisture in the outside air.

Keep that in mind when you see condensation on the outside of a car windshield in the AM. Same phenomenon in this case.

If you want it to never sweat, I highly recommend putting down plywood and be done with it.

That analogy is great, I'm glad that my original plan sounds good.
Thanks