The Hobbit Home
(two walls underground)

This is the home we had built in Pinson, Alabama, a little bit North and East of Birmingham.

It has 3 bedrooms and 3 bathrooms and a huge attic.  The downstairs living area is 2100 square feet and it has plenty of energy efficient features like spray foam in roofs/walls and a highly efficient and clean wood stove. 

There are 10" thick concrete walls where dirt contacts the house and standard 2x4 walls are built inside the concrete walls.  Obviously, we're not too keen on dirt roofs like the Hobbits, opting for a conventional metal roof.

Our 10½-acre lot is at 1200' elevation on Pine Mountain, and we own both sides of a small gorge.  We are planning to construct a small dam on this gorge and impound water to ensure we have plenty of water in the ground near the well.

Because the lot is heavily forested, we wanted the home to be as fireproof as possible.  Roofs are metal, exposed siding and soffits have Hardiplank (concrete siding), and our patio is concrete.  (Originally, we were going to install ironwood [Ipe] decking, but costs demand that we install a concrete deck instead.)
 

Here is a GIF of our progress so far:
 

It's getting long, so I broke it down

PART 1

PART 2

PART 3

PART 4

PART 5

A walkthrough https://youtu.be/AOdKPhDpi4s

A drive up https://youtu.be/GBmEtQ_wQL4

May 3 - House has been insulated with foam. Short YouTube video

May 13 - Sheetrock is hung and mostly mudded.  All exterior doors installed.  Roof rafters have been hung over the Sunken Patio.  Waiting for siding to be installed above and below the roof line, then the greenhouse panels will be installed over Sunken Patio.  With the foam installed, the house stays cool even during 80+ temps... as much as 15° cooler (usually 7-10 degree F cooler).  This house is sealed... no roof vents, no soffit vents and we have installed fans to introduce and exhaust air after flowing through the house.  (We are installing dehumidifiers as foam houses tend to be humid.)   

June 8th - Cabinets came yesterday... well, most of 'em.  We got enough cabinets to get our countertops measured today.  Countertops can take as long as a month!  The Pantry cabinets are not ready.  Septic to be installed tomorrow... we'll see...
 

June 26 - Painters almost done, electricians about 2/3 done, Plumbers hooked the house to the well and have most fixtures installed.  Septic system installed, so we have operational toilets (hate the portable toilet).  Carpenters pretty much finished the ceilings over the patio on Saturday while we split a face-cord of wood... hot!  Waiting on countertop granite and some cabinet doors and A/C guys...

The buried 100' Air Pipe is 6" in diameter and conditions outside air to the constant 63°F ground temp prior to entering the home.  It supplies warmer than outside air to the wood stove and the home in the winter and cooler than outside air to the home in the summer.  The home must be very air-tight for it to work efficiently and our home will meet that requirement as foam insulation is sprayed on the inside surfaces of all exterior walls and roofs, sealing the home tightly.