A QUICK AND INEXPENSIVE SOD IGLOO

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The only other construction supplies I needed were nails, spikes, staples, a few screws and hinges, 6-mil black plastic sheeting for the vapor barrier, glass (you could use plastic instead) for the windows, planking for the floor, and 2 X 6's for framing the door and windows. And since I was able to salvage some of these materials and trade for others, my costs remained low.

My tools were basic, but well suited to the job at hand. The collection consisted of a saw, hammer, axe, hand drill, pick, shovel, drawknife, screwdriver, and staple gun. I also used a level and square . . . but only when laying the floor and hanging the windows. Peeled logs don't have many planes or right angles, so the builder must learn to work with the wood, using its irregular curves to best advantage. If this job is done with sensitivity to the natural grain and form of each log, it can result in a structure that is far too beautiful to be considered a mere shelter against the elements.

Because a sod igloo is an earth-sheltered dwelling, it's very important that it be built on a well-drained site, with the depth of the excavation well above the water table. I chose a relatively high spot in a small clearing where the ground sloped slightly to the south, and began to (laboriously!) dig out a hole that would eventually measure 3-1/2' X 15' X 18'.

After first removing the top layer of sod in one-foot squares and setting that future insulation to one side, I got down to the single most difficult part of my task . . . actually excavating the site. Digging the hole — working alone and by hand — called for about four 20-hour weeks of backbreaking labor, but finally it was completed . . . and I could get on with the more pleasant task of framing.

I started that job by placing the pilings, beams, and braces as shown in Figs. 1 and 2. The pilings form and support the basic 9' X 12' rectangle that defines the house, and they had to be thick (at least 6" to 8" in diameter), strong, and straight . . . since they bear a lot of weight, including that of two layers of sod and of up to three feet of settled snow during this area's rough winters. To fasten the beams to the tops of the pilings and the ridgepole to the beams, I cut simple square notches — in such a way that the log frame could withstand the compressive forces of the dirt that was applied later — and secured the joints with 10" spikes.

Since part of the front of the igloo was to be left uncovered (it would accommodate the windows), I knew that the earthen load on the back wall would be much greater than that on the face. And (I figured), without some extra bracing, the structure would eventually begin to lean away from the greater pressure, becoming unstable. Similarly, the side of the dwelling opposite the doorway would be subject to extra berming stress. To counter these forces on the back wall, I installed diagonal braces from the tops of the rear corner pilings to points near the bases of those in front, butting them against rocks buried below floor level. I braced the wall opposite the door in the same way, except that in this case the front prop starts below the window. Finally, I ran another support from the midpoint of the ridgepole to the beam above the window to carry the pressures from the back wall to the front without stressing the poles that would constitute the structure's roof.

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