What are straw bales?
Straw bales are what you might picture when you think of bale of hay. They are a yellowish tan color and are made from the bi-product of grain crops, like wheat. The pieces of grain are typically tied together with twine.
What is straw bale construction?
In most jurisdictions, wood or steel framing serves as the structural support of the building. In straw bale construction, building walls are made of stacked straw bales. This is actually a common practice throughout history in some areas around the world. Straw bales have many sustainable and resilient benefits which is why we value the material as a great alternative material for residential construction. Hubbell & Hubbell Architects has designed and permitted over 40 straw bale buildings in San Diego County and is currently working on the first permitted straw bale home in LA County!
What are the benefits of building with straw bale?
- RENEWABLE & AFFORDABLE: Straw bales come from a highly renewable and environmentally friendly resource – they are typically made from leftover stalks from California rice crops. They are an annually renewable bi-product and are often considered a waste as they do not have a many uses. Therefore, straw bale are both inexpensive and easy to acquire. Although wood is also a renewable agricultural material, its renewal cycle is longer and it is considerably more expensive.
- LOW EMBODIED ENERGY: Embodied energy is a calculation of all the energy that is used to produce a material or product, including mining, manufacture and transport. Straw is produced by photosynthesis, a natural, non-polluting process fueled by solar energy. Substitution of straw bale for conventional building materials like insulation, drywall, wood and paint – which are all have a high embodied energy – reduces the energy used for processing and reduces the use of oil-based fuels.
- LESS LAYERS & LESS STEPS IN CONSTRUCTION: Straw bale walls eliminate the need for drywall, wood and paint. The exterior and interior finish is plaster. Below the finish plaster is a thick base coat. A wire mesh is tied to the straw bales and several coats of plaster are applied over the mesh. The mesh allows the plaster to grab onto something as it would not stick the straw bale alone. The base coat and plaster finish can be made right on site. The base coat is made of clay, sand and chopped straw. It creates a strong base for the plaster finish.
- OWNER-BUILDER FRIENDLY: The wall construction can easily be done by the owner and family or friends in a modern version of an old-fashioned barn raising. In addition to savings on labor costs, owners can have the satisfaction of living in a structure they have built with their own hands.
- NATURAL AND NON-TOXIC: Straw bales reduce overall health concerns. Substitution of straw bales instead of fiberglass insulation and other harmful materials avoids health hazards for workers involved in its manufacture and construction.
- HIGH THERMAL PERFORMANCE: Insulation and resistance to airflow are the key to energy efficient building and durability. Plastered straw bale walls are airtight and have a high insulation rating (R-40 to R-50) which is more than three times greater than typical insulation (R-12 to R-15). These energy savings for space cooling and heating continue to accrue for the life span of the structure.
- FIRE-RESISTANT: Plastered straw bale structures have a greater immunity to wildfire damage than other kinds of building. If the roof structure, exposed beams, and doors and window are made fireproof, a straw bale constructed building can survive fires that a conventional structure would not.
- UNIQUE & BEAUTIFUL: Straw bales are a unique and beautiful construction method. The material itself tells a story. Often times home owners want to expose part of the wall construction as a piece of art. In the images above, you can see a patch of exposed straw bale that will be covered with a piece of glass towards the end of construction.
- REDUCED PRESSURE ON FORESTS: Substituting straw bales instead of lumber can help relieve some of the pressures of logging and preserve our natural forests across the world.
Check out some of our straw bale projects:
Deer Park Monastery
The Boulder House
Gonzales Straw Bale Home
Friends Center
Spanish Straw Bale Residence
Smoketree Ranch
Solana Beach Straw Bale Home
Shimeall Straw Bale Home
Strawbale resources:
California Straw Building Association (CASBA)
International Straw Bale Building Registry
Straw Bale Testing Information
“We really enjoy our new [strawbale] home. It has lived up to our dreams so far. It stays cool in the summer, staying in the low to mid seventies most of the time, got into the high seventies a couple days when the outside temp was in the high nineties for a week. The winter temps are great. It has yet to drop under seventy except in the mud room, which we keep closed off from the rest of the house. We do use the wood burning stove; however, one full burn a day keeps it warm enough for t-shirts for 24 hours. It’s a great home, and a big hit for all those that have seen it. The home feels like a favorite sweater; warm, comfortable, and easy to move around in.”
