I too am curious what became of the need for the cheese cave that started this
thread.
Just my opinion here, so many variables, including the builder/cheesemaker's priorities, but I've been "researching" as in, struggling, with this question for awhile now.
I think if I can achieve the cooling without the high tech refrigeration units, I bypass the condensation problem AND the cost of running the compressors that run the refrigeration units.
I have very low humidity where I am, and when I am running in the 60s, I am very happy. I tried running a small humidifier for awhile but then I had trouble keeping the temperature low enough. And so when it is 8 percent humidity and 95 degrees outside and I hade temps in the 60s and humidity in the 60s, I considered that a success. I figure that people began making cheese in the pre-industrial era, and it is our high tech state of culture that even makes us try for the narrow parameters of 88-90% humidity and 55 degree F temperatures.
My cheese is not as moist after 8 months in my cave, as my friend who seals each of her cheeses in plastic, before putting it in her small "wine" cooler. But her cheese and my cheese are both delicious.
I think the different cheeses developed in their various regions because of the conditions in the aging spaces, including the endemic microbiome. The book "Natural Cheesemaking" <<
http://www.theblacksheepschool.com/david-asher>>is a great resource in encouraging interested folk to try living with the conditions they have, modifying them if they want, but accepting the cheese that develops as their perfect farmstead cheese. And you can name it whatever you want.
My stereotype of South Carolina is that it is humid, very humid, so that the highest priority would be to bring the temperature down. In humid conditions, evaproative cooling won't work, and if you put the cooling coils from your refrigeration unit into your cheese space, then you'll dehumidify in a hurry.
If you can dig underground til you get deep enough for the ambient temperature to be close to 55, that would solve everything, natural humidity and natural cooling.
If you can imagine or find out how people in your climate made root cellars, you will be on the "low tech inexpensive to operate" track.
One thing I might try would be to dig down deep enough to partially bury a shipping container, do the structural stuff around it to keep it from caving in, and above it adequate to support the load of earth above it, then back fill around and over it.
I think if you look at Paul's designs for
wofati rooves, they include dry layers of soil and moisture barriers. Dry soil does not weigh as much and I think is a better insulator. Alos worth considering would be a light clay "roof". though how you would get it to dry in the high humidity I am imagining in South Carolina is beyond me.
My ramblings have brought me to the idea that the building forum is the place to find ideas and expertise on low cost natural building. Clay and granite sound like materials with great potential. And since it is not for humans to live in, many rules that apply to living structures might not apply. But humans will be going in there and what ever you decide to do, make the structural support for the roof adequate to the load and then some. (I am overly cautious, I'm not sure I wold feel safe until I had 4 times the required strength for the load I was putting on top.