The Underground Hobbit House

An owner built underground cob and timber house, evolving over nine years and inspired by Mike Oehler’s book “The $50 and up Underground House.”

What follows is a photo tour of a nine year old evolving project and the construction notes of Glenn Kangiser. “My rule for the underground cabin is that it is built handmade using alternative materials that are, for the most part, found, salvaged or reclaimed.”

The Photo Tour

The cob construction fireplace and oven — Using cob construction for a whimsical oven/fireplace. (Who is the fellow with his tongue sticking out?). Glenn reports: “The head hanging on the post is called ‘Cobhead’- He’s my first attempt at sculpting anything out of cob.” When I mentioned that the fellow looked a bit like a recent political figure, he replied “Well, they do share the same brain matter.”

Below are earlier construction photos.

An owner-built underground cob house — Here you can see the basic construction. Log and heavy timber framing with about 18" of soil and compost on the roof. Simple sheds for drainage.

owner-built underground house — Well, maybe not so simple...

An owner-built cob house — An older interior shot with a bit of a Montana Lodge flavor.

Family room — Here’s the big family room where up to 30 people can gather. Ancient iron roofing panels were reclaimed as a wall finish and room divider. “The walls in the great room were stick framed with reject 2x4s and then covered with salvaged plywood from fruit bins. Next the walls were paneled with corrugated sheeting rescued from a burned out old gold mine mill, giving it that ancient ‘out of our price range restaurant’ look that custom commercial builders strive for today.”

The floor has its own interesting history.

“We have tried many different methods in experimenting with alternative floor materials. The front porch area is a cob floor covered with several coats of thinned boiled linseed oil. It is a more durable floor than the apartment area interior floors which are soil cement. The cement in the mix arrests shrinkage making the floor softer and easier to damage. The soil cement floors must have a new layer of sealer applied every few months to prevent dusting.

In the kitchen we partially solved that problem with the torn paper bag floor sealed and glued with layers of waterbase polyurethane. However the soft substrate still allows damage to it in places too.

We have finally settled on the CBRI light duty concrete floor designed in India and brought to our attention in Ken Kern’s book, ‘The Owner Built Home.’ This appears to be the most cost effective and durable floor of all. It is used throughout the great room (above) and the lower level of the house. Later we plan to refinish the upstairs floors with the CBRI floor system.

Variations of it that I have designed can be used over nearly any surface. Only 1/8 the thickness of most house floor slabs, this floor is colorful, environmentally friendly and as durable as a full thickness slab without the wasted concrete. Tractors need a 4" concrete slab... humans do not.

Plunger support piers are made in the soft ground every 2 to 3 feet with a tamping bar to get down to undisturbed soil. These holes are filled with grout and a 1/4" layer of a cement rich stucco is applied to jute reinforcement laid on top. This is followed the next day with another 1/4" final coat reinforced with fibermesh. Colors, as desired, are lightly troweled into the surface and then hard troweled for a smooth variegated finish. It is not necessary or desirable to compact the soil under this type of floor - the piers bridge the spaces and over time the loose soil settles creating an insulating air gap. Rated at 50 psf it is plenty strong, but in reality it has been tested at up to 250 psf and we have had no failures.”

kitchen and old cook stove area — This gives a feel for the kitchen and the old cook stove area.

gas cooktop — “A high end Magic Chef RV cooktop fit perfectly into the kitchen island and greatly improved our ability to rapidly burn a meal if necessary. The old (1935) C Wedgewood is now used mostly for baking but it is still working...just quite a bit slower.”

kitchen with Glenn and Kathy — Glenn and Kathy cooking on the new stovetop.

These two photos are an example of the plunger pile composite concrete floor (with color added). For more information on this inexpensive floor system click here.

more books — “Books give the impression of being scholarly even if I sometimes get too bored to read the whole book. The worn and studied books belong to Sassy (Kathy). So, to get people to take me seriously... I build lots of book shelves.”

A group photo of visitors who made a special request to see the Mountain Man’s cabin before his parents went back to China.

“A wild grape vine serves as a handrail for the spiral stairway up to kitchen level on the bridge. Grown to fit the curve of the stair by mother nature, all it required was a bit of shopping near an old gold mine and me going... ‘Hey, I know where I can use that... ’ Some day I will get the room under the bridge going too...as soon as I am ready for some jackhammer work.”

Guest loft over the pantry — “The guest loft above the pantry was added this year as were a lot of the other improvements. It’s just that sometimes it takes nine years to decide what you’re really going to do with otherwise useless space. In such a house as this things just evolve, without the need for predefined plans and code approved documents.”

solar panels going in — “Here is a shot of a new section of the solar array going in. This set takes the off-grid complex up to around 5000 watts of production from the panels. The wind generator is still putting out pretty much daily and even more during storms. We also have a 500 amp/10,000 watt welder/generator as backup for extended storms. I actually use the welder set on 220 amps DC for most of the charging along with the inverter charger to boost the batteries in time increments of about 1/2 hour during storms. We are still using some of the batteries we installed in 2004. We generally have enough excess power production in the daytime to run everything without drawing down much on the batteries.”

You can follow all the progress and banter of this and other projects of Glenn’s at his Forum Pages. Be advised, this thread has over 104 pages of ongoing forum discussion! (Glenn has explained just about everything he has built over the years.)

For a fun video tour of this house from Major Miracles (aka Mike Oehler), click below.

Where to go from here

Visit the CountryPlans home page.
Browse the Owner Builder Gallery for stories of other projects.
Ask general questions about building cabins and small houses in our forum.