The goal of green design is to create environments in which people are healthier, happier and more productive while minimizing the damage to our planet’s resources. The misconception that eco-friendly design is unaffordable is simply untrue. In some cases, it’s even less expensive than old-fashioned unhealthy design.
For example, gravel driveways are half the cost of concrete, and use far less energy to produce and install than concrete. Other features, such as radiant heating or solar panels, do cost more upfront, but they pay for themselves in time through energy savings.
Straw bales, a waste material from rice crops, are another inexpensive green building material, only costing a couple thousand dollars for most new homes. Straw bales serve as both walls and insulation. At two feet thick, their greatest asset is their insulating value.
Straw bales have been used for thousands of years. Our farmers grow enough straw to fill all of our country’s residential needs. Yet most people envision a straw bale wall burning down, or rotting or getting blown down. In reality, straw bale construction is just as strong and flame-resistant as conventional construction. A straw bale wall is actually less likely to burn than a typical wood-framed wall, which is 90 percent air, because there isn’t much space inside a straw bale wall for fire to travel. They are also extremely breathable, and resistant to mold production.
Because of California’s seismic codes, it’s necessary to utilize a structural frame with straw bales. For larger homes and buildings, steel, in lieu of wood, is most likely the way to go. Certified or renewable wood studs are greener than steel, which utilizes more energy to produce, but steel is quicker to erect, is straighter and more uniform than wood, and is mold and termite-resistant. Termites, in addition to mold, are a big issue in California since fumigation is very toxic. Prices are constantly fluctuating for steel and wood, and it could be that one option will be significantly less expensive than the other depending on the economic atmosphere.
Steel should be covered with mud to absorb condensation before plaster can be applied. More straw and mud must be packed into any empty spaces so there are no air gaps. A weed trimmer is used to trim the bales so they are as straight as possible in preparation for plaster, assuming that straight walls are the desired aesthetic.
Wire lathing is carefully installed on the straw around the windows and doors to create nice, square openings. Because of the thickness of the bales, each window has a built-in window seat. An electrical conduit can be placed directly into the hay with a notch for it routed in with a saw. Architectural accents such as niches also can be cut into the bales.
It’s crucial to also insulate the roof and in between floors, in addition to the walls. “Blue jean insulation” made from recycled denim trimming is a terrific option. It is soft to the touch and nontoxic, and diverts materials from landfills.
The foundation for a straw bale house can be constructed similarly to a conventionally framed structure. Rebar protruding from the footings every 2 feet is necessary to hold the first course of straw bales in place. Footings and foundations are constructed of concrete. The materials in concrete are all benign except for cement. The production of cement uses a lot of energy, and it’s difficult to recycle. Fly ash can be used in lieu of cement. Fly ash used to be a waste product captured out of the smoke stacks of coal burning plants and dumped. Now, it can be used in concrete.
Earthen plaster is the perfect finish material for stray bale construction, for both the interior and exterior. It is breathable, inexpensive and looks great.
Building interiors are significantly more toxic than the outdoors, even in the smoggiest cities. Because it has become obvious that our health and planet are in crisis, we now have no choice but to go green. In the near future, it will hopefully be unnecessary to differentiate. Green will be the standard.
— Elisa Garcia is the owner of Garcia Architects, 122 E. Arrellaga St. She can be reached at 805.856.9118 or email@example.com.