So I'm wondering if anyone here has done that and if there are any really special things involved. I'm thinking that all you need is to frame off a room, insulate it, and then do whatever you are going to do in terms of temp/humidity control. But I don't know whether doing the temp/humidity control puts any special requirements on the walls or ceiling?

My goal is to insulate and not have to provide additional cooling. The placement is on the North side of the home with 2 concrete basement walls providing cool mass. The framed walls are 2"X6" with 16" centers.

Initially the cellar will feature stained concrete w/ ample insulation and an exterior grade door sealing it off from the conditioned space. In the future, I envision an arched entryway leading to an arched cellar. 6 ft. tall racks lining 3/4 of the space and an island in the middle lit with task lighting for opening/tasting. I have already selected amber pendant lights for ambient lighting.

Flooring may evolve to cork. I will likely have a remote thermometor/humidity sensor such that I can keep an eye on conditions.

I have seen that with wine cellars the vapor barrier goes on the outside of the stud wall opposite the cellar side where the condensation would form if there were enough temperature differential and ample humidity.

Having lived 5 years in Sonoma County and seen many large collections the common complaint that I've heard is that it becomes a challenge to drink your wine before it passes it's prime. Note, this depends on how large your collection is and how much you consume. At a certain size, a wine collector may want to invest in a software application to track the inventory.

Long term, one of my goals for our 25 acres in the Pacific NW is to have wine grapes and a wine cave. Time will tell.

"someday" that will be my wine cellar :)
stucco walls, tile floors and all :)