I’m not a soils or geotec engineer, but I pay them to make sure that my buildings will not sink, tilt, or fall over… Its worth a few $$$ to hire one to tell you whether there are any subjacent, lateral support, or water issues if you excavate.
If your excavation disturbs the neighbors, including not just their structures, but also flora, topography, drainage, or earthquake risk, expect both lawsuits and insurance problems.
Andrew M, I did exactly what you described on the N side of my home in the PNW and have a great passive cellar that cycles nicely thru about 10 degrees around 55 . My big mistake was not putting in a moisture barrier in the floor. The high humidity is good for the wine but bad for the labels. Another piece of advice- no matter how big you build it, you will overfill it so don’t go crazy.
Anything above 3ft in height counts as living space here on Los Angeles. So very quickly you run into regulatory problems, how much sq.ft you can build on your land, slope analysis, geo etc. It’s just cost prohibitive in most cases. My geological survey was $9K alone here in Los Angeles. Add building permit costs, analysis, shoring, contractor, you’re looking at $50K easy for a simple dug out. My personal suggestion - do it without permits and work around the foundation.
I had a crawl space excavated out for my cellar and tasting room. It is totally worth it to have a structural engineer with all the credentials oversee this phase. Digging, tying it to your house’s footing, rebar, cinder blocks, sealant, tying together to the overall foundation, its all one logical unit of work IMO that needs to be well thought out in advance. We did hit some rather large boulders. Construction was what put me through school, I drew up the architecture and overall design and while I could handle it, its just more convenient [and faster] to farm out the heavy lifting through to the sheet rock. Also planned for an arced ceiling to give more of a cave feel throughout. Plan for your cooling system accordingly, vapor barriers, lights. Went with a WhisperCool Platinum ducted split system, all hidden.
After the heavy lifting, I reserved the more fun work for myself, the detail work. Painting, moldings, electrical fixtures, building and installing the racks, fabricating the base for the racks custom to hide the HVAC supply and accent the room.
And while not pictured, I did coat the floor with a sealant. As someone else noted prior, it does makes a difference. Left to its own, it would sit at 64 to 65 degrees. I keep it upper 50s. Humidity holds nicely.
A friend in London has one of these and he loves it. I don’t know if they sell them here and if they could be fitted with a cooler.
But their footprint is small.
All digging is dangerous [in terms of potential cave-ins], but digging around soil which is supporting a load is EXTREMELY DANGEROUS.
Also, many of those pseudo-soils in California always struck me as having effectively no structural stability whatsoever: The moment a big rainstorm comes to town, the soils super-saturate with water and the entire hillside goes sliding down to the ocean.
And, of course, in California, whatever basement structure you end up with will have to have been earthquake-proofed, which adds another huge burden to the successful completion of the project.
I’m not saying that it can’t be done, but if you do it [and do it right, and survive to tell the story of having done it], then it’s gonna be a BIG PROJECT.
fabulous.
This is a wise man…
FYI, This is a 5 years old thread! I moved on already 
Thanks for the input though!
Cheers!
JF
Blame me. I dug it up
I assume pun intended ![[cheers.gif]](/uploads/db3686/original/2X/0/0ff9bfcdb0964982cd3240b6159868fbdf215b1a.gif "cheers"){kind=small}