All natural earth berm?!

[youtube]My wife and I are currently wrapping up our first year on our 40 acre homestead in Eastern KY. We have so far lived in a Wall tent and are finishing our first building, (a timber frame workshop) which will be home until we get a house constructed.

Living so close to nature, in all its ever changing glory we have felt first hand the extremities of -30 this winter to +90 this summer.

We wish to design a home that uses no AC to cool in summer, a mass heater to warm and cook with in winter, and is built with as close to 100% natural, local, and sustainable materials as possible.

I started reading JRR Tolkien at the ripe age of 12, and have always loved hobbit style houses. We are leaning in the direction of an earth bermed home to accomplish our energy and shelter needs but are unsure of the best building method.

I have read Rob Roys book on underground housing, and though nice I don't agree with the concrete slab and plastic covered wood roof. He states a persistent problem with carpenter ants in his own houses and is unsure how to handle them…

I posted a while back on the idea of a cement block and clay brick barrel vaulted method/idea for an earth sheltered house, and though it seems viable, I do not like the cost and unsustainablility of that idea.

I have seen pictures of Viking houses built underground, as well as other (scottish) stone age buildings, which employ rock foundations and wood covered in sod roofs. These seem neat, though I am unsure how the comfort level was then? DId people mid mold and condensation in a home in those times? Or were there just bones, hides, and filth littered on the floor, and no one cared because you only lived to be 24 anyway? lol

But seriously, we are thinking maybe some blend of the (50 dollar and up) underground plan and a timber frame sheathed in Hemlock to be most ant retardant would be an option?

We have also considered a timber frame which has a level underground (such as a basement) but open to a roof (well insulated) would give most of the elements needed in our climate for a comfortable living area without AC and negate the issues with trying to waterproof a wooden roof…

I should note, on our site we have at our disposal all the clay soil, sandstone rock, timber, creek gravel, sand we can use. We have a local feed store who stocks OLDCASTLE brand type S (we believe) hydrated lime. We would be tickled pinkish if we could use only these natural and local things, but understand we may have to go and buy a few things.

I would welcome any ideas and comments. Ive seen such great ideas on clay/lime and other floors I'm excited to hear what might be possible. I will try to post a few links to our current builds to any who may enjoy.
Thanks
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I have looked at a lot of "hobbit holes" that have been built over the years and most of them have used some form of concrete to form the structures prior to back/ over filling with soil.
Like you I think these are some of the coolest structures ever, I have been toying with designs that have the internal structures timber framed as in Bag End.
It seems to me that if you did the excavation, laid a water impermeable membrane covered with foam insulation then put down a sand mixed with lime layer for a base then set stone or ceramic tile flooring, that would give you a nicely insulated floor.
The timber framing could be done in oak or any other suitable wood as long as you ended with an impermeable membrane, an insulation layer followed by another impermeable membrane. This would allow a soil over fill with protection from accidental puncturing creating seepage or leakage.
Following the same ideas, if you used rock for the walls and made sure your membranes were sealed to each other (floor to walls to roof) then you would have a total moisture proof wrapping of the house with the only points of concern being the roof air vents, chimney(s) and windows/ doors.

The interior of the rock walls could be lime plastered so the look would be just like the interior of Bag End. The real tricks to building a Hobbit Hole seem to be moisture proofing and weight of the soil. The Timber Frame (which is shown in Bag End) would be structurally strong enough to support all the soil weight.
The Rock walls, filling in the spaces would also be strong enough, since they would be at least 16" thick so the window and door reliefs shown in the movies and described in the books would be there. This leaves the water proofing as the biggest issue and challenge.

Good luck in your quest and I look forward to hearing more of your ideas.

I've been trying to figure this one out as well. https://permies.com/t/41924/earth-bag/design
That's one plan. The other is using tires as in earthship style. No matter what, not being in the desert, we need to worry about waterproofing the back and side walls. I think heavy poly sandwiched between foam insulation would be best. Less apt to have punctures in the poly. On craigslist, you can find used foam sheets 4'x20' taken from the big chicken houses. Less than 15 bucks a sheet. I used to always see the pink foam board but am seeing yellow these days. Thickness varies and I would think thinner would be better in my case as I want to have a radius in the back wall and thinner would flex more.

My tentative plan down here in the semi-arid central Texas is to use locally sourced (relatively speaking, within 100 miles) quarry block (2' x 2' x 5' limestone blocks) and build thick block walls lego-style. Probably very narrow, so that the roof spans could do earth covered fairly securely. Using pond liners and build above ground. I worry about moisture proofing when below grade. And torrential rains/flooding. But there isn't a single solution, and local climate matters a great deal.