My Mother's House

Enlarge Image Image Gallery This view from the southeast shows the location of the root cellar. (The window to the left was later filled in to allow further backfilling.)

As regular readers of this magazine know, there's been a team of alternative-construction specialists working on a variety of innovative buildings at the magazine's Eco-Village property—and gaining expertise as they do so—for the past few years. Under the direction of Jack Henstridge and Rob Roy, the crew (often with assistance from seminar attendees) built three cordwood structures . .. including the stackwood dome featured in issue 64. Furthermore, two of Bill Coperthwaite's wooden interpretations of the Mongolian yurt now grace the property.

Until recently, however, our team hadn't gotten the opportunity to put their experience to the test by building a full-scale, energy-efficient dwelling. But in the early part of this past April—with the summer's open houses and seminars rolling rapidly toward us—we finally started our earthsheltered house construction project!

In this issue we'll describe the initial phases of the undertaking. And—in order to explore the project in enough detail to benefit those folks who might use our successes (and mistakes!) to get through the building of their own energy-efficient homes—we'll report on the subsequent stages of construction in future issues of MOTHER. Finally, roughly 18 months from now, we hope to be able to conclude the story with an analysis of just how well our attempt at solarl-earth-bermed housing performs through its first year's heating and cooling cycles.

Western North Carolina's topography and climate lend themselves quite well to the earth-sheltering approach. Our area is blessed with an abundance of rolling hills—which provide plenty of sites where a home can be backed into a slope without the need for any particularly difficult excavation—and soils that have little expansive (prone to slippage) clay. Therefore, although drainage needs to be carefully considered, actual earth movement isn't often a problem hereabouts.

The region experiences approximately 4,000 heating degree-days annually, and can encounter seasonal extremes of 10" and 95 °F. A glance over a local monthly temperature profile chart indicates that some source of home heat may be required from September through May, and that cooling would often be pleasant in July and August. However, even during the hottest and coldest times of the year, the temperature will change significantly from day to night.

Consequently, MOTHER's house-planning crew decided that the inclusion of a large amount of thermal mass—along with the added "flywheel" effect of earth berming—would essentially eliminate the need for conventional heating and cooling. And we went on to take a few additional steps to tailor the solar-heated house to our particular climate.