Building Straw Homes
Straw homes and straw bale construction has attracted a lot of interest among green home and natural building materials enthusiasts since the 1970s. The process of creating an efficient, comfortable, strong, and healthy home from an agricultural waste product has gained a lot of acceptance among building code offices and traditional construction types.
Straw bale homes, when properly designed and built can outlast traditionally framed homes. The process is fairly easy, though it can be labor intensive. Despite the relative ease of construction, it can be vital to seek out the guidance of someone who understands the unique challenges of building a modern home out of straw.
The Attraction of Natural Building Materials and Techniques
Building with natural materials is an attractive idea for a variety of reasons to include better indoor air quality, a lighter planetary impact footprint, the ability to locally source materials close to your project, and the ability for homeowners to create large portions of their own housing without highly developed carpentry skills. Most natural material construction methods create remarkably energy efficient and comfortable homes. In addition, most natural materials building methods create homes with a unique aesthetic largely impossible when using standard stick-built carpentry methods.
Straw Bale Homes
Straw bale homes typically take on one of two forms—either the structure of the home is made up of a timber frame load-bearing system with straw bales in-filling the walls or the building is actually built of straw with stacks of rectangular straw bales making up the entire wall. The straw home walls in both cases are arranged in strong and durable running-bond stacks, much like oversized bricks. Both methods have a number of variations depending on climate, site conditions, codes, and methods preferred by the builder.
Both straw home construction methods produce strong and remarkably efficient homes. The load-bearing straw option has the benefit of simplicity and lower cost, while the timber frame method may be desirable in areas with high winds, extreme snow loading, or seismic stability concerns. Which of these two systems is appropriate in a given area is usually a matter of local residential building codes. Check with your local building department for specific requirements for your project.
Straw Homes Are Energy Efficient
Over the life of a typical residential structure, straw bale walls will have the potential to save enormous amounts of energy and money in heating and cooling efficiency. In a variety of studies, straw bale wall assemblies have been shown to have R-value equivalents ranging from 13 to 55, depending on the testing method used, the way the wall is finished, and other variables (Commins and Stone, "Tested R-value for Straw Bale Walls and Performance Modeling for Straw Bale Homes," 1998 ACEEE Summer Study on Energy Efficiency in Buildings Proceedings, and Stone, “Thermal Performance of Straw Bale Wall Systems,” Ecological Building Network, 2003).
The common rule of thumb among straw bale builders places straw wall insulation performance at around R-30, far superior to common wood studwall insulation systems.
As a comparison, typical wall insulation in residential new construction would be R-11 in southern regions and R-19 in more northern areas. When the conductive heat loss of framing members is factored into these typical walls, the effective insulation values are far less. Straw bales walls, on the other hand, have almost no perceptible conductive heat loss as they have far fewer interruptions in the insulating layer due to their lack of stud penetrations.
Homes Built From a Waste Product
The straw bales used in straw bale homes is not hay. Hay is a food source for animals, has comparatively minimal strength, and is a haven for insects and rodents. Straw, on the other hand, is the strong cellulose stalk of a food crop such as rice, wheat, oats, barley, or flax. The food source husk of the plant has been removed and the dry stalks are otherwise a waste product that has been traditionally used as animal bedding, in erosion control, or (most commonly) burned in the field. Using a common hay bailer, straw is baled into rectangular 14”x18”x36” straw “bricks.” These bricks are low cost, stable, fire resistant (when encased in plaster) and in many areas, this building material is plentiful. Since the food portion of these plants has been removed, the bricks are also not attractive to rodents.
Easier Construction, But You Still Need Expertise and The Willingness to Work Hard
Straw home walls go up quickly and relatively easily. The monetary savings on a straw home in the form of cheap materials and the possibility for untrained people to do a fair percentage of the work is often lost in labor costs associated with applying lime plaster to all surfaces of the wall structure. Many do-it-yourself straw home builders find that they become discouraged with the amount of work needed to coat their walls in layers of plaster and work the surfaces into a presentable finished product. If you are forced to pay for this labor, the construction costs of a straw home can quickly balloon.
In its current incarnation, straw bale building has been pursued since the 1970s, however evidence of straw bale homes dating from the Paleolithic era has been found. With all that history, straw home building has been around long enough that quite a body of knowledge has been amassed about how to make a lasting, comfortable home without issues of mold, water infiltration, or in-wall condensation.
Don't expect to just start stacking straw bales without a lot of planning and fact finding. Either hire a builder with experience and a good track record of straw home project success, or seek training and guidance from a true straw bale building professional.
Get A Free Strawbale Home Framing Report
Hands-On Preparation To Build Your Straw Home
Andrew Morrison, of Oregon has built countless straw structures and has taught thousands of contractors and homeowners to do the same. He conducts building clinics around the world and has a series of instructional DVDs as well. His videos are a good primer, but if you are serious about building your straw home, an investment in hands-on training will save you time, money, and a huge amount of potential frustration. Andrew can be contacted at
The Straw Homes Bottom Line
- Straw homes are made from a product that is often either burned or wasted.
- Straw bale homes are often exceptionally energy efficient.
- It can be relatively easy to incorporate unique features such as curved walls with straw bales.
- Straw and natural plaster can create excellent indoor air quality (depending on other materials used and ventilation).
- Straw bales are an inexpensive building material.
- Straw bale walls naturally breathe.
- Thick walls and deep window sills provide a unique building aesthetic.
- Straw wall construction is technically easy, though training is needed.
- Some local building codes may not recognize straw construction, or may limit methods.
- Straw bales may not be appropriate for extremely wet locations.
- Some may not appreciate the look of thick walls, deep window sills, and plaster exterior wall surfaces.
- Straw walls may need to be protected from repeated direct wetting in damp environments, necessitating design parameters such as extended eave overhangs.
- Some banks may have a problem lending for a straw bale construction project.
- For resale, some potential buyers will need to be educated regarding straw building misconceptions.
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