Straw bale buildings can be an incredible eco-friendly methodology to build a barn structure, storage facility, or personal residence. With the green building movement’s rapid rise, more people are looking at this construction system to bring their dream facility come to life. While it takes a bit of skill and craftmanship, many owners opt for a self-building technique as a relatively inexpensive solution that requires limited assistance from professional construction companies.
We have compiled a few considerations for your straw bale construction project:
A Green, Esthetic Choice:
Straw bale constructions are made of natural materials that can be used in a variety of architectural styles and design types. Their material is 100% biodegradable and, if well maintained, can last over 100 years. An advantage of straw bale construction is the thickness of their walls (up to 18-20 inches), which is often a sought-after and esthetically pleasing feature in homes.
The straws are usually made from wheat or rye, and require relatively low energy to produce, with sunlight as the main energy source to grow the plant. The bailing process and transportation also have energy requirements that can vary depending on how far they are shipped.
Straw bale buildings are great at keeping you warm, as they have a high thermal resistance, or R value. Their insulative wall yields an R value of 30-40, considered on the higher end compared to other conventional materials used in buildings.
While the straw bale walls are very efficient insulators and prevent heat within the home from escaping, adding a cob-like material (usually made with clay and sand) will increase the thermal mass in the building. This cob-like layer will store solar energy inside during the day, allowing for much smoother temperature gradients between the outside and inside. The high insulation value of straw bales coupled with the thermal mass of the cob-like coating offers a great solution to keeping your house warm.
A common misconception is that straw bale buildings are very flammable. And while individual straws have a high ignition rate, the straw bales used in construction are very densely packed, leaving little space for oxygen, thereby making combustion more difficult. Interestingly, straw bale constructions are generally considered less flammable than other types of conventional home construction.
Straw construction is a great option for cold or warm, dry climates but are not recommended in regions with high levels of humidity and rain. The main challenge with straw bale construction is their susceptibility to moisture and mold. Straw bale walls are a breathable, vapor-permeable system, and require a very good roof and foundation in place to prevent moisture accumulation. Outside render coating the straw bales should ideally be made of lime plaster, which offers a good resistance to adverse weather conditions.
Another consideration is to determine whether straw bales are readily available in your region, as the opposite may incur high shipping costs. It is also recommended to check your local codes and regulations to ensure that straw bale constructions are permitted. You may want to consult with an architect or lawyer regarding what process is required to get your plans approved.
Straw bale construction offers an energy-efficient solution for both structures that add character to your barn design, or as stand-alone buildings. For builders looking at a more self-sufficient and eco-friendlier lifestyle, this methodology is proving of great value!