How do I actually 'seal' a sealed grow???

I'm going to be building a detached garage just after the 1st of the year. I understand just about everything with regards to a sealed grow (A/C, heat, humidity, water, lights, electrical, etc..). EXCEPT how to actually seal the room.

DO I need to install a heavy plastic 'vapor barrier' on top of the insulation but behind the sheet rock? What else should I do?

There will NOT be any windows and only 1 door that will be a commercial type heavy-duty metal door with car swipe access. I will use a split a/c system to heat/cool the room and I will recycle the air inside and filter for odor control. There will be very limited air coming from outside. I will also supplement with CO2.

I'll attach a screen capture of the plans for the garage...As a side note the plans currently show 2 doors and 1 window. These will be removed during the build phase. The shop will be for flowering and the area marked 'storage' will be the veg and mothers/clones. Obviously this doesn't show the electrical or mechanical that will be installed. I plan on using a combination of 120v & 240v in the room. I will also have a sub-panel located in the garage.

What are your thoughts?

Mine is double walled and insulated , the inside wrapped with mylar and the outside sealed with construction foam. All the 3 door seals I sprayed a ton of foam all around the edges, let it dry then cut the door free with a razor. Moving blankets cover each door too to help hold in anything that may trickle out. Basically foam and silicone will be your best friends. Lots of tricks out there to get the job done tho, hope it helps