Alternative building practices

A mix of old and new technologies pave the way for a new future

Straw Bale Enclosure Systems

Straw bale construction is comprised of four main components: straw, clay, sand and water. Square straw bales are systematically stacked, creating an enclosure system. Approximately two inches of an earthen plaster is then applied to the interior and exterior of the building. Between the 14 inch width of the bales and several inches of plaster, these buildings offer superior insulation and great thermal mass. With proper design and building techniques, the straw bale wall system allows a building to be outstandingly energy efficient, boasting an impressive R-value of 30 to 40 or better. They are virtually fireproof, breath well, and are non-toxic. Local materials are at the heart of this sustainable building technique. Straw is a byproduct for many local farmers, and using local sands and regionally colored clay can allow for a unique house with low embodied energy.

Cobb

Cobb is a form of earthen building in which a mixture of clay, straw, sand and/or gravel is piled on a wall while wet and worked into place. Considered a very artistic style of building, cobb can be formed to almost any shape. It has good thermal mass, but poor insulation. Therefore, it’s a superior building technique for small complex buildings, interior walls, ovens, and solar heated buildings that need thermal stability.

Straw Clay

A variant form of cobb is a "straw-clay" mix in which long strands of straw are tossed in a clay slip, allowing it to bind together, but not get clumpy. One of the oldest straw-construction techniques known, straw-clay is a traditional European system for making medium-weight insulating infill for walls and roofs. It is made on site, and rammed between forms.

Earthen Plasters and Floors

Earthen plaster, interior and exterior, offfer aesthetically rewarding patterns and colors. Plasters in the Eastern United States are usually composed of shredded straw, sand, and clay. Earthen pigments, sometimes naturally occurring in clay , micas (biotite and muscovite) and limewash are all added constituents of earthen plasters.

Earthen floors are made up of similar components. They are applied after the ground is prepared by removing topsoil, compacting the subsoil and laying down several layers of gravel. These can be left unfinished, or topped with a variety of natural waxes and oils to create a beautiful, long lasting floor.

For further reading on all of these technologies, go to the information page to find other links and articles around the web.

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