Hey guys I wanted to pull your coats, and get some help with this grow room I’d like to frame out in an uninsulated garage. This will be my first departure from tents to rooms. My main question is how to properly ventilate it but any other feedback would be killer.
Top space is 5x5 flower area. Bottom right is 2.5x5 veg space. Bottom left is entry room with utility sink and ac unit.
Looks tight to work and move in…
Instead of framed walls would blackout curtains work? The door swinging into a 2.5 foot room would make it real tough to work around.
For the doors- use pocket doors or barn-style doors to maximize floor space
Framing- try to find structural foam panels if you can, used is just fine. My ex’s parents built a superinsulated chicken coop out of those in a 8” thickness and the birds did just fine out there through 0F winters and kept laying with just a pair of heat bulbs going, which is pretty unusual. Failing finding that at a good price I’d sheathe the walls internally with garage door foam paneling, it already has a shiny alumnized face that is waterproof and pretty reflective. Framing could be pallets if you can find a bunch of clean and matchy ones for free, a double stack on the long way with the rails acting as vertical studs is just the right height for a garage, just sister them together with more scrap wood. Pile some fiberglass batting on the roof when you’re done for more insulation.
Ventilation- if it’s in an unheated garage you probably want to run it recirculating internally with scheduled exchanges from the garage air, which will be then need to be heated. If you could pull your fresh air, if possible, from the foundation or cellar of your house instead of the garage? That air will be way warmer and moister than raw winter garage air and save you on heating costs. Exhaust could just be through a window register or one in the wall, or really whatever.
I agree with @GCBudz that the design looks really tight to work in
I would read a bunch of @ReikoX ’s posts about his grow room build and how it works, it seems like that’s what you’re going for in a simpler form and he’s got it dialed and documented. This isn’t his current log but it starts with a good overview of the system:
I’d be inclined to do this instead 
though I’m not an expert. Usually you want the veg room more humid than the flower, so it seems to me you could economize on your heating and humidifying sending it through the flower room into veg then out. 
Thanks, looking at a similar situation myself. Much appreciated 
Happy to help as I can!
How many lights do you plan on running and what kind? What about a humidifier and dehumidifier? If you are going to install mini splits then you should make both rooms completely sealed which means you will need to supplement co2 a monitor, controller, and a tank. You could run a couple scrubbers and only worry about fresh when you dump your co2 at lights off. I’ve heard anywhere from 3-5 btu per watt of hps. So I imagine with LED you could do 3-4 btu per watt and be able to keep it cool. Not to mention everything else that is electric and running in the room causing heat. Do you plan on hand watering or installing an irrigation system? If you run hps and sealed hoods you could mitigate a lot of heat pulling fresh cool air from the garage through all the hoods and outside or in the attic /crawl space. I wouldn’t advise pulling from your crawl space though imo I think that would introduce a lot of pathogens dependent on how old the house is. I’m currently building a room and these are all things I’ve had to learn and think about. What about environmental controllers will you be running any of those?
