The Building Codes
Societal Impact Matrix
Return of The Village
Habitat For Humanity
Curves of Breath & Clay
Overview of Techniques
Nature, Earth & Magic
History of Cob
Cob Q & A
Compressed Earth Blocks
German Clay Building
Earthen Plaster & Aliz
Solar Water Heater
A Hybrid Hobbit House
In preparation for the 1995 Natural Building Colloquium held in Kingston, New Mexico, my husband Pete Fust and I surveyed the land around our Black Range Lodge for project ideas. Inspired by our visit to Thierry Dronet's straw bale workshop in France, we wanted to emulate the way that structure seems to grow organically from the earth. On a steep hillside under some gnarled old Alligator Juniper trees, we decided to build a rustic camping-cabin that could be comfortable for three seasons, to shelter friends who might stay for longer than a night or two. Somehow we started calling it "Casa Chica," and the name stuck.
As the name implies, it's a small space less than 200 sq. ft but we wanted to combine as many natural building techniques as possible into it the design benefiting from the advantages of each. Before the Colloquium, Pete dug a flat site into the hillside, which was not ideal for solar gain, as it faces north. During the Colloquium and over the next year and a half, many creative minds and loving hands contributed to the evolution of Casa Chica, which was built primarily using materials from our own backyard.
As the Colloquium began, Ianto Evans led a visioning exercise on the site, encouraging participants to create from their hearts. Joe Kennedy spearheaded building an "earth-bag" retaining wall/foundation for the south side. A narrow trench uphill of the south wall was later lined with a plastic moisture barrier and filled with pumice to create a "French drain" to direct ground water around and away from the structure. Michael Smith supervised a mud-mortared rock foundation for the east, west, and north walls, which was topped with a layer of earthbags as an easy way to level the stem wall in preparation for straw bales. Short lengths of PVC pipe were placed at intervals below the earthbags as "chases" for later tying the top-plate to the foundation.
Robert Laporte and Sun Ray Kelley demonstrated "scribing" the bases of the wooden posts and door-frame, so they rest solidly on stone plinths. A decades-old hand-hewn beam Pete found became one corner-post, and most of the lumber in the building Pete (and friends) harvested from the nearby Gila National Forest. The crowning beauty of Casa Chica is the forked Juniper tree used as a ridge beam. The center support poles were scribed to receive its Y-shaped trunk, which forms a south-facing clerestory to help maximize solar gain.
Bill and Athena Steen led the construction of load-bearing straw-bale walls on the north and west, with 3-string bales laid up for the first two courses, then 2-string bales completing the wall. Robert Laporte demonstrated light-clay straw construction to form Casa Chica's east wall, which includes a window and the doorway. Near the end of the Colloquium, he also proved the fire-resistance of light-clay/straw by holding a propane torch against the wall for twenty minutes, creating only a small circular hole in its surface.
Post-Colloquium, Sun Ray installed a wall of windows above the earth-bag retaining wall on the south. Building 2x6 frames for recycled glass panels, he actually bent the tempered glass into a curve that mimics the curvy flow of the wall. The windows are tied into the wooden corner-post and the center carrying beam. Then all gaps on the south side between the earthbags and window frames were filled in with cob. Offering thermal mass, cob was also ideal for filling the odd-shaped gaps created by wood in the round. Two-gallon bottles were cobbed into the southwest corner, to great effect. Space for a solar oven and a dug-out "earth 'fridge" were also incorporated into the south wall.
Bill Hunt helped mastermind a unique top-plate for the straw bale walls using curved Juniper branches to follow the curve of the wall. He attached the top plate by tying heavy baling twine through the PVC foundation chases, and also staking it into the straw bale walls. Larger curved Juniper branches were selected for the rafters between the roof beam and top plate, which was then surrounded with cob, as a kind of bond-beam. The roof decking is Ponderosa pine, custom-milled on site to a mere 1/2 inch, which allows the boards to bend across the curved Juniper ribs, forming a roof shaped like a wing.
As the design evolved, a sleeping loft built with Stramit decking was added to the east side, creating a covered entry-way. We also decided to add on a bathroom, and this prompted us to dub the place Casa Chica Grande! Sun Ray went on to sculpt a corner fireplace from cob, embedding stone foot- and hand-holds for climbing up to the loft. Above the roof, the cob chimney is protected by spiraling flat stones to deflect the rain.
At the spring '96 Colloquium, many new hands helped with further work, which included a section of wattle and daub on the east wall, and a section of "poured adobe" floor. Both the interior and exterior walls were finished with earth plasters. The inner walls are a medley of unique designs, images and nichos created by many different individuals.
Pete used a bitumen rubber roof membrane called "torchdown" to seal the pine decking, while Francois Tanguay was on hand to demonstrate his method of creating a "living roof" above the waterproof membrane straw bales are laid tightly together forming a layer of insulation, then their strings are cut. On Casa Chica, whole bales would block the clerestory windows, so we used flakes of straw. We'll later add manure to create a better growing medium, and plant some strawberries up there. Pete plans to add a sprinkler system on the roof, both for irrigation and to reduce fire potential.
Frank Meyer recently put in the tamped earth floor. Still to finish are the clerestory windows, the earth floor and final aliz plaster. A custom-made door will be framed with planks of Juniper fitting snugly over the rock threshold. But we've already enjoyed many warm fires in the cob fireplace and friends have christened the sleeping loft, though it's still open to the stars. And as the building has progressed it has inspired many to expand their ideas about what a home can be.
Like something out of a fairy tale, Casa Chica is a flowing structure of curves and natural shapes growing from the earth. Evolving into being through the creativity of many, one can feel the energy and love that is now embodied in the straw, mud and timbers. Our intent in creating Casa Chica was to show that a comfortable, beautiful space can be built almost completely of natural materials, in a sustainable way. Now, much more than a camping cabin, we're thinking of moving in ourselves!
Catherine Wanek is the director and producer of The Straw Bale Solution as well as the Building with Straw series of videos. She is a director of non-profit NetWorks Productions and is Managing Editor of The Last Straw. She and Pete Fust have hosted three Natural Building Colloquia and numerous workshops and conferences at their Black Range Lodge.
Star Rt 2, Box 119, Kingston, NM 88042; ph (505) 895-5652; email <firstname.lastname@example.org> or <email@example.com>; on the web, see www.strawbalecentral.com and www.zianet.com/blackrange/lodge/
This article was originally published in The Last Straw Issue # 17 and is reprinted with permission. HC 66 Box 119, Hillsboro NM 88042; ph 505-895-5400, fax 505-895-3326; firstname.lastname@example.org, www.strawhomes.com
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