Hi. I hope you don't mind a few questions. Where are you located? What is the plastic material? Is it reflective? What are you using for ventilation? What are the floors made of? How do you water? It looks nice and there is plenty of room for shelves so you could double or triple the amount of usable space.
OK here goes. I am located in the U.K. This grow room is under a new addition to the house. The walls are concrete block and the ceiling and floor are poured reinforced concrete. There is a drain in the floor.
The material on the walls is mylar to reflect the light. In the last photo
you can see two green water butts and the RO unit above them which keeps them topped up. You can also see in that photo a Flo Jet water pump which draws water from the tanks at 60 psi. I use a garden hose attached to the pump and a garden watering wand to water the plants. The floor drain takes care of the run off.
I have two other 'subterranean' grow rooms and do not have a problem with them heating up. The maximum temperature I have recorded in the other rooms is 29 C even during the hottest weather.
It is easy to wet down the floor and walls and the humidity never falls below 70%
There are two large fans running 24/7 and an intake and exhaust fan which come on during the night to cool the room down and lower the humidity a tad. You can see the exhaust fan in the block wall in the last photo on the top right. The intake fan is on the opposite wall at the same height and has alumninum tubing to take the cool air from outside to the bottom of the grow room.
That looks great! I'm blind now, as my retinas are burned out, but it looks very bright in there. What are you growing in your two other plant rooms? I've got some of that reflective fabric(quite a lot actually) that I got in a package deal when I bought a bunch of flow tables. You've reminded me I have to do something with it. Maybe ebay.
If I ever have a grow room, I'm going to be a basement dweller, too.