Someone who calls himself “Earthbag Hero” made this comment on my blog post several days ago where I outlined a discussion I led about underground building:
5 years ago I was researching all these issues and finding solutions for the bermed earthbag dwelling I’ve been working on for the last 4 years. Now the building is watertight and held a 43⁰f advantage (no heat yet) against the recent winter storms and zero temps.
It’s interesting that you mention burrowing animals as a disadvantage, as I considered this as well even though I couldn’t find anyone else discussing that aspect. I used 3″ of crushed limestone gravel to protect my waterproof membrane. Then about 3″ of soil on that. The gravel has an extra benefit of allowing rain to flow off the building without digging valleys and taking the soil with it.
Before I started construction I actually got Owen’s stamp of approval since it’s fairly unique. I wrote more about it here in a recent reddit post, including a few pictures and sketches lower in the comment section.
I’m currently working on the floor and plastering walls. Likely a year left to go, but I gave up serious estimations a long time ago. I can say that all of the trees for the posts/beams/rafters came from my place, mostly from a few hundred foot radius. Also, I plan to finish around 20k$, as I’ve done most of the work myself and reclaimed what I could, including all the free windows.