A builder’s perspective on the straw bale homeBy Bobby McHugh on 03/16/2006
Though skeptics abound, the modern straw bale home is the flagship of the green-building movement. A well-done straw bale will use resources wisely, inspire and comfort, and perform efficiently throughout its life cycle. Before we were married, my wife and I thought about how great it would be to build with straw. Lured by the natural curves, the recycled nature of straw and the erroneous claims of constructing a house for less than $50 a square foot, we looked into it. How expensive could it be? It’s straw! With some hands-on experience and serious design and planning, we learned the first lesson of straw bale building: the straw is just the walls. Eventually we built and moved into our home, learning many lessons along the way, especially about what green building meant to us.
Wheat straw, the most common local variety, is the stalk of the wheat grain plant. The straw exceeds half the weight of a harvest of grain and is typically burned or baled to use in erosion control. Straw is a waste product. If you consider building the walls of a house with a waste product, you may think you can build the whole thing using recycled products. In fact, most straw bale builders find all sorts of alternatives to store-bought products: mosaic granite floors from the waste pile, windows from demolished fast-food restaurants, and wood milled from the house site are but a few examples.
Your home is outside all the time. It needs a good hat, a good pair of shoes and a warm coat. This is especially true of the straw bale home that will brave the elements of the Appalachian Mountains. Straw homes have an enemy in moisture and need to stay dry inside and out. Deep overhangs keep unwanted sunlight out and are the first defense against falling rain, keeping the bales nearest the foundation away from splashing water. The foundation can be made of any material though a radiant-heated slab is the favorite locally. Positive drainage, in which the landscape slopes away from the house, and a diligent drainage plan will help keep the wall sills dry. A passive-solar design suits straw walls. Heating with the sun in the winter keeps the bales dry, and taking advantage of cool breezes in the summer does the same. Stucco coats vary a lot in local straw bale homes. For strength, most contain a little Portland cement, which is partly-hydrated lime. The more lime the better because lime’s alkalinity retards the growth of mold. Seeing a bale rotting with black mold after it was left outside in the rain would make you think it would happen instantly to a mildly-wet straw wall, but our mostly lime and sand-covered walls have never shown a sprig of mold.
Keeping with the green-building creeds regarding material use and the fact that building with straw is labor-intensive, straw bale homes are not typically big. The mentality is that you design a house for what you need. There is a humility in the straw bale home that points to all the trees, all the steel, all the stone and sweat that produced it. The straw bale house is a departure from the material-hungry mansions of our time. There is no way to make a 6,000-square-foot home “green,” not even with straw walls. The straw bale home asks: what do we need? If every homebuilder, designer and developer would ask that question, we might have enough resources for the next generation to build.
Your home can warm your heart and feed your soul. To ensure that, build a sacred space. It doesn’t have to be a temple or altar. In our house, it’s the sleeping porch. Napping on an outdoor bed full of blankets and pillows in the sun with a book over my eyes is my idea of heaven. Have a space in your house that you can go to just to feed yourself. This goes for non-straw-walled houses, too. Each of the lessons I learned building with straw taught me about the most important points of green building, and I believe building with straw will teach others as well.