No. 23 : Winter/Spring 2009
Reviews Interview
ARTerrain
Unsprawl
To Know a Place
by Kathryn Bundy
For those who have never spent a winter in Montana's Rocky Mountains at 6,500 feet, where temperatures plunge to 40 below, the thought of passing two in a nine-foot by sixteen-foot trailer while building a few dwellings, evokes a visceral sensation of suffering.
When Californians Christopher Borton and Linda Welsh found 90 acres bordering Beaverhead-Deerlodge National Forest near Whitehall, Montana, they parked a trailer, dug in, and began to realize their dream of building what has become Sage Mountain Center. The buildings are a combination of cordwood and straw bale, powered off-grid by the sun and wind.
Linda Welsh and Christopher Borton founded the Sage Mountain Center in 1990.
Photo by Kathryn Bundy.
Sage Mountain earned its name because of the ubiquitous sagebrush that the young couple tried to eradicate from the site by dragging a mattress around behind a pick-up truck. After crushing the resilient bushes within a circumference of their future cordwood and straw-bale buildings, they had auspiciously spread a carpet of seeds that sprouted into five times the number of bushes they intended to eliminate. Though the couple was only trying to clear building space, they realized early on that they were merely one of many species either visiting or rooting at the site.
The builders had all along considered the creatures with which they'd be sharing the property. In fact, Welsh says they "thought about what animals use to build shelters at 6,500 feet and went from there." They have no dogs so as to encourage the wildlife in their habitat as much as possible.
Borton and Welsh built the center from the surrounding trees, earth, and straw first to teach themselves the basics of building sustainable, off-grid structures. They have since become trainers for hopeful owner-builders who intend to design and build their own cordwood and straw-bale homes. As a consultant, Borton now travels around Montana as well as conducts seminars on the mechanics and day-to-day operations of drawing solar and wind energy to power daily needs.
The center grew out of experiments with cordwood from trees they felled, "slash" limbs that had been cut from logged trees and left lying about, soil, and some cement. Beginning nearly twenty years ago, they felled 140 lodge-pole pines after the forest service issued them a permit for $70—often managing seven- to eight-foot sections of wood from single trees. They used the slash for structural beams as well as for creating unique furniture, stair railings, and doorframes. Because moisture evaporates quickly at that altitude, the readily found pine, fir, and aspen were well-preserved.
While the detritus left from logging in the 1970s and the forest service's fire-suppression practices have created a tinderbox, the couple began practicing forest restoration by cleaning and thinning particular sections of the property. They then seed with native grasses in the spring after having a fat stack of wood for the stoves all winter.
The Sage Mountain Center entrance displays the mix of lodgepole pine and cordwood wall that is decorated with bottles to allow the passage of light.
At the center, timber frames the main building, whose north and west walls are straw-bale infill with an insulation value of about R-40. R-value is a material's measure of resistance, per inch, to heat flow. At its best, straw bales measure about R-2 per inch when a bale is placed on its side in the wall, averaging about 20 inches in width. The south and east walls are cordwood, at R-25, with an interior eight-inch bed of sawdust. Positioning cordwood in the south wall—along with the thick layer of insulation—creates a high thermal mass that stores energy "like a battery" throughout the 24-hour cycle of large fluctuations in temperature, says Welsh.
Earthen plaster covers interior and exterior straw-bale walls and serves as a mortar between pieces of cordwood. The builders mixed it from surrounding topsoil, as well as sand and cement, to increase durability against the harsh climate. Mixing the plaster "mud," which many call it, demands much from builders, who must move quickly while it is wet. Welsh and Borton did what they could to time the need for mud mixing with visits from friends. But for the most part, the two did most of the building themselves.
They poured cement floors, which are heated with in-floor hydronic radiant heat. Water heated from a combination of sustainable methods courses throughout the floors that are also warmed from the sun that passes through south-facing walls averaging 50 percent glass.
The warm, late August day I visited Sage Mountain Center, the temperature had dropped to 19 degrees the previous night. Linda said they often experience four seasons in a day, and it was especially true then, as the next day's temperature climbed into the 50s. As Borton described the two winters he had spent in the trailer while beginning the project, the dedication and perseverance was palpable. Sharing a trailer with exploding cans of food as the temperature plunged and feeling pressure changes as if in a diving submarine, Borton drew on his training as a Catholic Monk years before. He likewise had to remember the winter while assembling cordwood walls, laying insulation, and mixing mud in 95-degree, fly-biting heat. The urge to reduce the amount of insulation was strong, causing him to repeat a "remember 40-below" mantra. The couple had to design efficiency into the building at every turn.
The south-facing wall of Sage Mountain Center contains about 50 percent glass to capture the sun's heat in chilly Montana winters.
Sage Mountain's energy feeds from a combination of solar and wind power, which, along with wood-burning stoves in the winter, heats the center's air and water and powers the electrical appliances. The structures consist of the main building, where they conduct classes, a one-and-a-half story guest cottage, and a one-room cottage, named Tilting Tree Cottage due to the angle of a large nearby tree.
A friend from California, Warren Hill, serves as the caretaker and lives upstairs in the guesthouse. The day I visited, Warren was stripping bark from cut trees intended for an upcoming cordwood project.
While the center is beautifully crafted, careful attention to the use and circulation of energy creates a more organic structure than the typical home that Americans have taken for granted. Today's owners and builders rarely factor the site, terrain, and climate into the construction of most buildings or homes, which are designed to be plopped down, plumbed, and wired into the grid to draw on centralized water and power. In their book Building Green, builders Clarke Snell and Tim Callahan concisely describe the typical, manufactured American home as one that is diseased: as if on a life-support system, the archetypal home in the United States is one that is hooked up to the grid that supplies heat, cool air, electricity, water, and light. It can be built—or assembled—in nearly every environment, regardless of site criteria, with materials trucked in from around the country.
The philosopher Martin Heidegger described dwelling as a basic element of our humanity. We build in the sense of cultivating the surrounding earth so that we may dwell, which is the primary way to connect with our environment, not overtake it. Before building Sage Mountain, Borton and Welsh considered all the siting criteria, including the region, climate, altitude, drainage, sun, and water availability.
A percussionist as well as a former figure skater, Borton comes from three generations of builders. To hear him describe the renewable electric system that runs through what he calls the energy "heart" of the main building is to hear multiple generations of builders in one—clearly focused on fusing old and new technology.
Borton and Welsh designed the inside of the one-room cottage for ultimate efficiency and light.
As Borton tells it, the energy heart of the building is "like the hara of the body," the center of gravity in a person, from which energy emanates throughout the organism. The main control center, or "heart," contains what he calls the circulatory, nervous, and digestive systems. Water circulates throughout the main house through plumbing that connects from the solar hot-water panels on the roof to a storage tank housed in the "heart." From the tank, heated water is plumbed to showers, sinks, and floors in an open loop that also includes the hydronic floor heat. Should the solar panels be unable to heat the water enough during winter, a backup tankless propane water heater is ready for on-demand needs, much like a pace maker is used only when necessary.
Additional water-heating help from a greywater heat-recovery system strategically funnels warm greywater through separate plumbing into a buried 55-gallon tank. The tank's plumbing houses fresh water separately, which the used water warms about five to seven percent, reducing the amount of electricity required to bring it up to temperature in colder months. Though five to seven percent may not seem like much, it counts when synchronizing multiple systems throughout the day.
After preheating fresh water in summer, the greywater flows to the outdoor wetlands. In winter, it runs into a septic system. This "digestive system," as Borton calls it, keeps nutrients within the Sage Mountain ecosystem. It stays on the mountain. Human waste is methodically turned into compost outdoors at regular intervals after resting in sawdust in hand-made composting toilets for a period of months. Though the job of turning human waste into compost sounds repellant, it actually rests long enough for the bacteria to break down the waste into compost.
Borton says that composting the "humanure," what the couple calls the compost, "is slow, taking about one year to complete the cycle."
The electrical, or "nervous," system runs from the sun through photovoltaic (PV) modules with a tracker on the roof, and from the wind through an 85-foot-tall wind generator. The generator, which pulls in about 25 percent of the center's power, begins cranking when wind blows at seven miles per hour, reaching peak power at 24 mph. Batteries, which are inverted from low-voltage DC power to higher-voltage AC power, store the energy. The center consumes about 5,000 watts of electricity per day, about one-fifth of that of the average American home, and it uses only about one-third of the total renewable electricity supply that its sources generate.
Well-preserved wood from the Sage Mountain Center site serves many functions, such as this handrail.
Photo by Christopher Borton.
To warm the air, Borton and Welsh designed an efficient system that partly mimics the way a human's skin and lungs absorb sun and oxygen that then circulates throughout the body. They strategically placed thermosiphoning air panels (TAPs) to draw in cool air and warm it before it flows into the house. The vents in TAPs pull in outside air that the sun then warms before it flows out of top vents into the house. In the guesthouse, a roof TAP passively preheats water in a tank for showers, and strategically placed water coils in the wood-burning stove ensure water is hot.
Welsh is a registered nurse with an M.A. in transformative learning and change, and they are both yoga instructors, and so offer a range of seminar courses on physical health and sustainable living. Welsh is also steeped in the philosophy of deep ecology and in their twenties, the couple found inspiration for their venture from the early-twentieth-century natural builders, Helen and Scott Nearing.
"Knowing that one other couple has done it made it easier," says Borton.
He is referring to the Nearings' decision during the Great Depression to move from New York City to rural Vermont, where they built stone dwellings and lived sustainably for 60 years. They educated visitors on living much more simply in what became known as the "back to the land" movement. Today the Nearing's Vermont buildings have become a museum of sorts, modeling the methodologies that have inspired people for two generations.
When Welsh speaks of how she and Borton learned to build their center, she reiterates what many experienced owner-builders say—that, depending on the structure and climate, building a dwelling literally from the ground up requires careful planning, reading lots of books, the willingness to start small and experiment, and the ability to adapt and learn from mistakes.
Salvaged wood stool crafted by Borton and Welsh.
Welsh says "they broke it down and started small. We experimented with smaller buildings with plumbing, electricity, and cement floors before building the main building."
As Borton was researching how to build a sustainable septic system, he found only scant mention of the greywater heat-recovery system in an article. He spent ample library time gleaning what he needed to build it. And then plan. The two builders created fairly detailed five- and ten-year plans to get to where they are. Their next goal is to grow as much of their own food as possible. They're planning a year-round greenhouse, which, according to Welsh, "has great potential because of the strong, nearly constant sunlight."
In the building of their current structures, Welsh and Borton never used any heavy equipment for lifting. Welsh says she "learned a tremendous amount about how women adapt to build what has traditionally been built by men. Because so many of the basic tools have been essentially designed by and for men, women friends who came to help build had to find their own systematic—self-organizing—methods of teamwork to lift heavy materials or synchronize efforts by each taking on a different task. It was amazing."
The current economic meltdown, and specifically the housing-market crash that is casting thousands of homeowners out of their homes, gives owner-builders an additional, acute reason—on top of climate meltdown—to consider building sustainably. Much like the illusion of security that became endemic throughout the home-financing world during the first decade of the 21st century, the buildings in which we typically spend vast amounts of time do not meet the basic needs of the surrounding ecosystem. And such a statement in itself leads to the question what does sustainable mean?
A word with multiple meanings—yet often used in tandem with development and growth—often implies that we consume when we develop sustainably. But what of the give and take? We cannot help but consume; the question is how much—and the degree to which our existence in the surrounding environment resembles something closer to co-habitation than parasitic behavior.
Sage Mountain's idyllic quality is easily apparent in late August, with the scent of sage and pine filling the air, both inside and out. Even when winter temperatures slide well past frigid, the PV panels and recycled glass windows heat with abundant sun, allowing a person to experience the raw side of the mountain from a sheltered spot, devoid of exploding cans of food. And the elk can chew the tree bark, coyotes can hunt the mice, and badgers can forage for roots and eat insects.
Kathryn Bundy is a freelance writer living in Ohio who just completed The Complete Guide to Alternative Home Building Materials & Methods. She has been a community organizer, working with people to develop democratic authority on sustainable food and energy issues.
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Title photo (left): Sage Mountain Center near Whitehall, Montana. Photo by Kathryn Bundy.
Earthwood Building School: Cordwood Building
The Good Life Center at Forest Farm
Montana Green Power
Rocky Mountain Institute
Sage Mountain Center
StrawBale.com: Straw Bale Construction
Think Green Building
Cordwood / Straw Bale Construction
Straw Bale Basics
Generally, a local supply of straw exists, depending on the locale, keeping money circulating in the local economy, thus reducing transportation costs and energy use.
Straw is often burned, so using it reduces the amount of CO2 emitted into the atmosphere.
As a quickly renewable source, straw can be harvested every year.
It is best purchased immediately after harvest and stored in a dry, well-covered location until it is used; see actual bales to ensure they are dry and free of mold (moisture meter should monitor less than 14 percent water content).
Ensure bales are of uniform size and tightly bailed.
Cereal grains (wheat, rye, barley) are best for bales; alfalfa is not sturdy enough.
An excellent insulating material, straw bales are thick, ranging from about 14 to 24 inches, and depending upon how they are stacked (on their side or standing up) their R-value varies from about R-28 to R-40.
Bales are either stacked within a post-and-beam structure, or they are load-bearing (also called monolithic), in which the bales themselves bear the burden of the structure, including the roof.
Load-bearing bales are tricky, as a lack of proper planning or building techniques could leave the structure unstable; it is important to ensure the roof does not compress the bales.
Cordwood Basics
Cordwood is often available locally, reducing transportation costs.
Be sure to use clean, seasoned, and barkless wood that is not infested or rotting, and is stored in a dry location.
The best choices, especially for wet climates, are poplar, cedar, and pine, which shrink the least.
Hardwood requires extra protection, such as plaster coating, in wet climates.
Cob masonry used between pieces of wood has less embodied energy than mortar,
but the cement in mortar provides more protection from the elements.
Cob is a mix of clay, water, and sand.
Mortar is a mix of sand, lime, soaked sawdust, and Portland cement; adding water-
soaked sawdust to mortar makes it more insulative and helps it adapt to weather changes.
Sawdust or vermiculite insulates between the wood in the walls' center, helping the R-value, which can be up to about R-25.
Siting and Design
Site away from where water either collects or runs, and use the natural environment as much as possible as protection from the harshest elements (trees, hill).
Solid design and wide overhangs ensure water does not run down walls.
Water damage can easily occur if structures are not carefully sited, designed, and built.
More protection is required in wet climates, such as using cement in earth plaster used on walls.
Seal straw bale walls with silicate paint to prevent rot while maintaining vapor permeability.
Linseed oil waterproofs cordwood ends but allows vapor permeability.
Plaster interior and exterior of straw bale walls for protection and durability.
Ensure walls are hygroscopic — that they allow water vapor to pass through — or trapped water will cause damage; use permeable plasters (earth, lime).
Higher foundation walls and sill plates help protect from water.
Straw bale home photo by Nathaniel Corum, courtesy University of Texas at Austin School of Architecture. Cordwood home photo by Andrew Lund, courtesy Home 'n Stead.
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