Building a Straw Bale Home in Southern California

Ultimate Home Design magazine did a wonderful write-up of a project our company, Mountain View Construction, recently completed in Central California. With permission from the author, Paula Aiton, we're republishing it here so it will be accessible online. Enjoy!

Straw Bale Construction in Central California
By Paula Aiton

Reprinted from Ultimate Home Design

For homeowners Ira and Brady Rubin, building an energy-efficient home in Visalia, California had long been a dream for the couple and their family. Now a reality, the 3500 square foot home, built using straw bale wall construction, sits on five acres of land just outside of town with a sweeping view of the nearby Sierra Nevada Mountains. In an area of Central California where agriculture is the primary industry, and the idea of hay or straw might be more vividly associated with livestock, this type of construction is becoming more and more popular as a means to achieve many goals, not the least of which is energy efficiency and fire protection.

For many years, the Rubin’s grown daughter, Daryn, had been reminding them, "There is only one issue: the environment!" When she and her husband, John, invited the Rubin’s to create a family home with them and their small children, the entire family embraced the concept of building a sustainable home. They considered a variety of sustainable materials: SIP panels, rammed earth, adobe and even discarded tires. In 2005, they participated in a straw bale workshop with the company, Real Goods, in which they built a small kiosk for a river-rafting company. After that experience they were "sold on straw bale," Mr. Rubin said.

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According to Stuart Rigney, General Manager for Mountain Vista Construction, Inc., the home incorporates many energy efficient features. "The primary benefit of using straw bale construction is the increase in insulation properties", he said. "Straw bale walls have an insulation rating of R50 compared to the typical R13 or R19 in traditional lumber construction with blown-in insulation or expanded polystyrene insulation." As a builder, Mr. Rigney also said that construction using straw bales was relatively simple to research and implement. The building process was uneventful and did not stand out as more difficult or significantly different from other construction types. In fact, Mr. Rigney said that constructing the walls was very much like stacking up children’s building blocks.

Located in Visalia, California and serving the entire State, Mountain Vista Construction has become known as a cutting edge contractor for sustainable construction in many residential and commercial projects. In addition to their experience with a variety of eco-friendly housing types, they are also a developer of sustainable workplaces and are the design/build contractor for a new office building in Exeter, California that is seeking LEED Gold Certification. "Although the initial construction cost may be up to 5% more than a more traditional structure type, a sustainable building will immediately begin to pay back the owner in energy savings", said Mr. Rigney. The company has shown their clients that building Green need not be cost-prohibitive, while proving to other contractors that building responsibly can be profitable.

The Rubin’s home was designed by Tom DeVore of the award-winning firm, The Drawing Board of California, also in Visalia. As a member of the American Institute of Building Design and with thirty years of experience designing custom homes, Mr. DeVore had extensive experience with traditional wood framed designs. After some research into straw bale construction, it became clear that the deep overhanging roof eaves that the Rubin’s requested for internal solar control would take some special engineering and design for roof loads. As a result, the entire roof structure is supported by timbers that were harvested as leftover snags from a forest fire, adding further to the home’s eco-friendly construction. The timbers were compacted eight feet into the soil and set in concrete. Hand-peeled of their bark and treated with a fire retardant, the timbers are now an integral part of the home’s nearly fireproof construction. The windows of the home are deeply set into the walls while the roof eaves extend eight feet beyond to create a wrap-around veranda that evokes the feeling of an Old California-style villa. The overhanging eaves have the added benefit of protecting the interior from the heat of the intense Central California summers. Mr. Rubin is prosaic when he describes his new home, "Plastered organically, straw bale breathes; there is no off-gassing. Straw bale lasts; there are bale homes in Nebraska that have been standing 200 years. Aesthetically, it’s delicious; thick walls create an undulating shape, like a warm castle, that is both organic and substantial."

With the load of the roof extended beyond the straw bale walls to the timbers on the veranda, the Rubin family could take advantage of an interior design that was not constrained by the need for bearing walls. Large open spaces perfectly suit the family, which is comprised of the Rubin’s, their grown daughter, her husband and their four small children. A Great Room in the center is multifunctional, used for gatherings, entertainment and home schooling. Four bedrooms are on one side of the home for the growing young family and the other side of the plan contains a suite of rooms designed specifically for Mr. & Mrs. Rubin.

Other features were incorporated into this home to reduce indoor pollutants. For instance, the use of cellulose insulation in the attic space instead of traditional fiberglass, stained concrete floors containing plumbed radiant heat within instead of carpet or hardwood, and a tank-less water heater which reduces the energy output traditionally spent by natural gas heated water tanks. In addition, a two-car garage is not attached to the home, but stands separate from it, thereby reducing the amount of vehicle pollutants that might otherwise enter the home. Although currently on the grid for electricity, future plans for the home include the installation of solar panels on the roof for free, and even profitable, energy. Extra energy they produce can be sold back to the power company during peak summer months.

Considering that the primary element of this home’s construction is rice straw, an undesirable agricultural byproduct that is traditionally burned by farmers, it is gratifying to the family to have contributed to the environment by removing something from it. This one project represents at least many tons of rice straw that did not become part of the breathable air. The San Joaquin Valley, of which Visalia is a part, is well known for its poor air quality. Particulate matter from agricultural refuse burning is a large contributor to an increasing problem. Allergies and asthma are on the rise for residents of the Valley and it is not uncommon for very young children and senior citizens to have severe respiratory problems associated with its poor air quality. In addition, burning rice straw after harvest has many regulations placed on it and there is a tangled bureaucratic puzzle as to what to do with this refuse product. Although farmers are also allowed to flood a certain percentage of their fields to encourage the rice straw to degrade, flooding is a waste of another precious resource: water. Using rice straw from Northern California fields also provides a reduction in secondary environmental impact. In this project, the rice straw was grown and harvested within 500 miles of the project site, reducing the need for long distance transportation. Rice straw, as a primary construction material, is also rapidly renewable, replacing itself every year.

It is interesting to note that the acreage on which the home is built shares a neighborhood once owned by a enclave of Quakers. When subdividing the property into many five-acre plots, the Quakers developed Codes, Covenants, and Restrictions (CC&R) that required that all construction by the new owners be sustainable. As a result, the Rubin’s nearest neighbor lives in a rammed earth home and yet another neighbor is in a home constructed of adobe brick. It is clear that the Quakers long tradition of a simple life and peaceful coexistence with the land influenced their desire to steward the future of this property.

As Mr. Rubin has said of their experience in building Green, "In the end everyone benefits. The builder profits, the owners save dollars and live in a vital habitat. Most importantly: the planet gets a little healthier."

Paula Aiton is a freelance writer who lives in Hanford, California with her husband, a licensed architect and LEED Accredited Professional, and their young daughter.