> Since so many people have asked about what happens when it rains, here is Shera's response: "Baldassare actually put drainage systems in place! Many of the rooms are built on a grade and sump pits are placed in strategic areas throughout the Underground Gardens where the water is directed to collect and reuse. While it does get muddy underground, we do not deal with any serious flooding."
My whole childhood I dreamed of digging secret tunnels and chambers all throughout my future house and yard etc. Imagine my dismay when I found out about water table and ventilation :-(
Presumably this wouldn't work in areas that flood, but Fresno isn't one of them. I also wondered about earthquakes, which are a risk in some parts of CA.
Yes. Because it can be semi-insulating (straw bales) or it can be externally insulated. Mass isn't just mass ... it needs controls and energy input. A hole in the ground is attached to the ground and that's the end of the story. No control. No thermal inputs.
You can accomplish better insulation and thermal mass above the ground, while having better ventilation and less humidity.