Have it your way...
In the early '80's I did some contract work for a guy in southern Oregon,(Grant's pass area) that carved a similar house out of a decomposed granite hillside.
The wall/roof construction was very similar to the PASH, but was insulated on all sides with expanded poly styrene foam and sealed outside (dirt side) with 40 mill plastic/ vinyl? sheet and roofing tar. (hot mopped) with a granite look stucco inside. Total sq. ft. was ~4500. The south wall was fixed lite double insulated glass covered by sliding perforated metal screens to regulate the heat gain. Several poly bubble "sky domes" in the high sloping roof gave the interior an airy feel, not at all "cave like". Each bedroom had it's own emergency egress via a long horizontal 60 inch dia. concrete culvert pipe with an access door on each end. In the hottest part of the summer, filtered outside air was drawn in thru them with a 6 foot dia. slow turning 8 blade fan, to provide natural A/C. Several small "boxwood" stoves provided suplimental heat in the winter. the average year round interior temp was around 68/69 *F thanks to the 2 ft. minium dirt depth on the roof and full coverage on the outside walls. As far as I know, he never pulled a permit or had the plans inspected, (he was a retired civil engineer) he just paid cash for materials and labor, hid the most visible parts with creative landscaping and lived happily ever after I guess. RED
