Green building in ecovillages: Diana Leafe Christian shares the ups and downs of building simply

New Life Journal, April-May, 2002 by Diana Leafe Christian

Sustainable building is an inexact science and its adherents are learning all the time. Like other ecovillage founders, we've learned a great deal about what works and what doesn't work at Earthaven, a permaculture-based intentional community on 325 acres near Black Mountain, NC. Like most aspiring ecovillages, we use passive solar heating, roof water catchment, off-grid power, composting toilets, and small homes of mostly natural or recycled materials.

Learning to use natural building materials from your own land is one way ecovillages try to live sustainably. In our own attempt to learn this, we combined several methods in one of our first buildings, a timber-framed Council Hall. We used peeled by not milled logs from the land with either traditional timber-framed joinery or bolted joints, and 26 logs radiating from a central cupola to span a 35-foot interior. Because we wanted to learn several different traditional methods for wall infill, we made the northern walls strawbale, for insulation, and southern walls straw-clay and cob, for thermal mass, with large windows for solar gain. We plastered the interior and exterior surfaces with earth and lime plaster.

Like many ecovillage residents, we began a more ambitious building project than we could finish easily. As a first step towards having a "living roof," we covered the roof with EPDM, a rubber-like sheeting often used for pond liners. And for a while, we had no floor in the center of the building just old carpets over the dirt. Whenever it rained and the wind whipped the EPDM back our roof would leak, and wet carpeting and dirt would create mildew. So anytime after it rained when we'd walk in into our beautiful, natural-built "sustainable" building, we'd get knocked over by the smell, and some people in our Council meetings wore air-filter masks. But nowadays our EPDM is more secure, our floor of red maple and walnut (milled from trees on the land) is nearly finished, and the place smells fine. Let it rain!

Builders at Sirius Community in Massachusetts, another ecovillage project, also tried new methods when they built their 12,000 sq. foot octagonal Community Center. Like us, they timber-framed their building, used a mostly circular shape, and attempted to span a large interior space (in their case, fifty feet.) They also explored innovations, such as a unique wall construction method to reduce the use of wood and reduce heat loss, blown-in cellulose insulation, and two composting toilets. Like us, most of their innovations worked, but they also learned some lessons--their building is warm and toasty in winter and cool in summer, but one of their composting toilets never worked.

Ecovillagers usually build their homes on the same general principles, but suited to the natural materials of their bioregion. In our case, all homes are passive solar heated backed by wood heat or propane (most are on south-facing sites), and many are earth-bermed on the north as well. Most are round-pole post and beam construction with thick walls of straw-clay in fill or lath and plaster with blown-in cellulose insulation. All have green metal roofs, and most are earth-plastered or earth-and-lime plastered in shades of reddish-orange and apricot pink. Members of Dancing Rabbit Ecovillage in Missouri, however, use methods suited to the prairie. Since wood is scarce and straw plentiful, they build their passive solar homes of load-bearing strawbale, and any lumber must be recycled or grown locally. To keep homes cool in summer, they use white metal roofs to deflect the sun's heat, and their earth-and-lime plastered exteriors are a pale cream.

Like many other natural builders, we learned it's not necessary to use chicken wire over strawbales before plastering. In fact, the first coast of earth plaster adheres better if you just mash it directly into the prickly straw surface. We also learned from those that went before us that using such plasters means thinking about the effects of weather, so plastered buildings must have sturdy foundations and wide roof overhangs.

Ecovillage residents are also partial to recycled building materials. One of our homes, still under construction, is an "Earthship," a specialized kind of passive solar building made of recycled tires filled with rammed earth and stacked like bricks into the south side of a slope. Another building under construction, a large multi-family home, uses recycled 4x4-foot pallets sheathed in 3/4" plywood as a major building material. The pallets comprise the sides of four-foot-square plywood and plastic-lined "juice cubes" that fruit juice processors use for shipping. The family hauls the discarded pallets home from a bottling plant in a nearby town, and, using floor joists on four-foot centers, they then drop the pallets into place like gigantic floor tiles for a rock-solid subfloor. They detach the plywood squares from other pallets to use for sheathing the walls and roof. The only down side is that the pallet supply may not last.