SHELTER: The core of the low-cost homestead is the 1,000-square-foot, two bedroom earth shelter described in the accompanying article. Instead of conventional rectilinear construction, we've chosen a more structurally sound round design . . . which allowed us to use 8" concrete block, rather than more expensive 12" block or a poured wall. In addition, the circular plan yields significantly more useful floor space than would a square building that used a similar amount of material. For example, the exterior walls alone have 11 percent less surface area than would a square building of equal floor space.
A greenhouse with built-in planting beds extends south from the living room, and will provide both fresh greenery and a solar heating boost for the dwelling. During summer, however, an overhang shades the greenhouse, kitchen, and clerestory windows from direct sunlight through the hottest part of the day.
Naturally, we chose to insulate the building to the extent that our project's finances would allow. And you might be surprised to find out that, even on less than $10 per square foot, we managed to afford a ceiling value of about R-26 and wall R-values anywhere from 13 (on the most heavily bermed portions) to as much as 41. (We left the slab uninsulated . . . though folks in more extreme climates might want to alter
Backup heating will be provided by a Vermont Castings Vigilant woodstove located almost in the center of the building, and that unit's capabilities will be enhanced to some extent by a mass wall of
high-manganese brick built behind the woodburner.
The home's domestic water will be solar heated — by a batch device set at the face of planting beds located outside the kitchen windows — and H20 consumption will be kept to a minimum with low-flow faucets and a Seiche One toilet that uses less than a gallon per flush.
Finally, the earth-sheltered design should keep maintenance on the building to a minimum . . . allowing most of the occupants' energies to be devoted to work on the sustainable agriculture systems.
And, moving beyond the practical, we've been pleased to note that most people find our earth shelter more pleasant to be in than the average conventional home. Generous amounts of glass in the greenhouse and kitchen keep the spacious living room/ kitchen day-lit, and the combination of operable casement windows in each bedroom (these portals also offer fire exits) and a full-width clerestory bounces plenty of sunlight around on the white walls and ceilings of those areas. (In fact, even the bath has its own clerestory.)
ENERGY: Our building is wired for either 12-volt DC or 110-volt AC electricity. The low-pressure juice will be supplied by a tiny hydroelectric plant fed by the creek that's immediately adjacent to the home and should make up the majority of the power needed. With about 70 feet of fall, we hope to be able to produce approximately 150 watts of electricity on a continuous basis. While this may not sound like much power — and indeed, in conventional terms it isn't — 150 watts per hour will add up to about 3.6 kwh per day . . . easily enough to operate lights, an efficient 12-volt refrigerator, and an occasional small appliance. This electricity will be stored in a battery bank located in a shack next to the main structure. Backup power, and high-demand loads, will be supplied by a 6.5 kw, liquid-cooled Honda generator . . . which we've already used to power some of the construction tools.
Space heat will, we hope, be almost entirely sun-provided, since the energy demands of the structure should be very low because of its conservative size, earth sheltering, and insulation. There are still likely to be times, however, when the woodstove will have to be lit. Whether or not those demands can be met with cleared brush and cull trees from the one acre remains to be seen. But, in any event, the quantity of wood that might have to come from the property should be small.
PERMACULTURE: The earth-sheltered house is a major feature of MOTHER EARTH NEWS' Low-Cost Homestead, but it's by no means the most important element. As stated above, our goal is to establish a one acre mini-ecosystem composed of many diverse — but mutually interdependent and beneficial — features. Each segment (including the house, gardens, pond, and outbuildings, along with the various plants, animals, and people inhabiting the area) is intended to perform several different functions, and should contribute to the well-being and efficient operation of the others, creating a harmonious and productive whole.
This type of design is based on the concept of permaculture, a term coined by, Australian gardener Bill Mollison. Formulated as a result of Bill's realization that human beings need to heal their relationship with the earth, permaculture's underlying philosophy might be expressed as "Live lightly . . . and let live." Much has been written on the subject, including an article in MOTHER NO. 77 ("Designing for Permanence", page 82) . . . but, in brief, permaculture systems forego regular, violent disruption of the soil (such as annual plowing) and the use or importation of exotic plant and animal material. Instead, they utilize and enhance the natural features of a site (such as its elevation, solar orientation, climate, winds, soil, and native — and especially perennial — plants) to develop an environment capable of fulfilling human needs (those of a small family, for instance) with a minimum of disturbance to the overall ecology. It is an attempt to "fit in", rather than "redo".