This is an earth-sheltered home in Armington, Illinois, built in 1977 by Andy “Caveman” Davis. It has more than 2,300 square feet of living space, a curved concrete exterior and a bermed roofline. The listing calls it a massive blank slate.
508 S Jefferson St, Armington, IL 61721 — $59,000
Built to Beat Rising Energy Costs
According to the listing, Davis built the house to combat rising energy costs. It was engineered for natural climate control long before modern eco-building trends. The roofline is bermed, so the house blends into the landscape.
The outside has an undulating concrete shell. The home is one story, and the construction material is listed as concrete.
Features:
- Built in 1977
- Earth-sheltered, one story
- Undulating concrete exterior and bermed roofline
- About 2,300 square feet
River Rock Ceilings and Arched Corridors
The ceilings and arched corridors inside are covered in river rock. The listing says the Davis family hand-collected the rock on annual trips to Colorado.
Features:
- River rock ceilings
- River rock arched corridors
- Rock hand-collected on trips to Colorado
A Blank Slate
The house is not finished inside. The listing says the structural footprint gives you the framework to finalize a 5-bedroom, 2.5-bathroom layout. The data lists 5 bedrooms and 3 baths.
The listing suggests a few ways to go. You could restore it as a single-family cave house, run it as an Airbnb, or turn it into a multi-unit property.
Features:
- Framework for 5 bedrooms and 2.5 baths
- Listed as unfinished, a blank slate
- Single-family, Airbnb or multi-unit potential
Two Electric Meters
The property already has two separate electric meters. The listing says that streamlines a potential duplex conversion. It points to this for anyone who wants to add a unique asset to a rental portfolio.
Features:
- Two separate electric meters
- Possible duplex conversion, per the listing
Windows Included
The sale includes two brand-new, uninstalled Argon gas circular windows. The listing puts their value at $15,000. They are meant to replace the old windows down the road.
Features:
- Two new circular Argon gas windows, not yet installed
- Listed value of $15,000
Utilities, Lot and Parking
Heating and cooling are both listed as none. Water is public, and the sewer is a septic tank. The lot is about 0.33 acres, and the listing counts 6 parking spaces.
Features:
- No heating or cooling listed
- Public water, septic tank
- 0.33-acre lot
- 6 parking spaces, no garage
Schools and Taxes
The home is in the Olympia school district. The listing data shows Olympia West Elementary rated 9, Olympia Middle School rated 7 and Olympia High School rated 8 on GreatSchools. Those schools are listed 5.5 to 7 miles away. Annual taxes are listed at $1,857.
Features:
- Olympia West Elementary (PK-5), rated 9
- Olympia Middle School (6-8), rated 7
- Olympia High School (9-12), rated 8
- Property taxes of $1,857 a year
Price
The house listed on September 24, 2026 for $59,000. That works out to about $26 a square foot.
This is a lot of house for the money, and it is a big project. Someone with a vision for a cave house, a short-term rental or a duplex should look at this one closely.
Full Listing Description
Built in 1977 by Andy “Caveman” Davis to combat rising energy costs, this original earth-sheltered home in Armington offers over 2,300 square feet of highly efficient underground living space.
Integrating directly into the landscape with an undulating concrete exterior and bermed roofline, the home was engineered for natural climate control long before modern eco-building trends.
Inside, the property features a distinctive architectural aesthetic with ceilings and arched corridors covered in river rock, which the Davis family hand-collected during annual trips to Colorado.
Currently presenting as a massive blank slate, the structural footprint provides the framework to finalize a 5-bedroom, 2.5-bathroom layout.
For those evaluating multi-family utility or looking to add a unique asset to a rental portfolio, the property is already equipped with two separate electric meters, streamlining a potential duplex conversion.
Whether restored as a unique cave house – single-family residence, an income-producing Airbnb, or a multi-unit property, the opportunities are endless.
The sale includes two brand-new, uninstalled Argon gas circular windows (a $15,000 value) for the new buyers to replace the old windows down the road.
All Photos
