I have been a big fan of Earthship Biotecture for several years. In fact, it was my interest in Earthships that led to my interest in other forms of alternative construction methods, which in turn led to an interest in natural building. I own, and have read, all three volumes of Michael Reynolds' Earthship series of books. I've also had the opportunity to visit and tour the Earthship at Blue Rock Station near Columbus, Ohio.
Even as I began to explore other alternative construction methods, I maintained an interest in incorporating earth rammed tires into my plans. I even have a pile of old tires that someone in a nearby town was giving away for free. I figured that it was a good idea to go ahead and start collecting tires, since I would surely be using them in a project at some point in the future.
On the surface of things, what is not to love about the idea of building with a waste product that would likely spend years in a landfill if not put to better use? It seems like the best of both worlds, the tires are being reused, rather than going to a landfill, while at the same time preventing the need for new material to be manufactured for the building process, and saving the homeowner money.
I have began, however, to worry about the potential health and environmental impacts of using tires in this way. Like most topics, information exists to support both sides of the argument. Those who believe building with tires to be completely safe, including Michael Reynolds, say that the tires are not an off-gassing danger, and that by being packed with earth and covered in plaster they are protected from the elements that would eventually lead to decomposition and cause leaching. Those concerned with the safety of earth rammed tires, however, often point to the studies that conclude that tires should not be used in gardens or landscaping applications where edibles plants may come into contact with them. In these situations it has been shown that the tires do leach a toxin that can kill certain plants.
Personally, I don't feel there is sufficient evidence to support either case at this time. In situations such as this, where I feel the evidence does not provide a clear answer, I tend to go with my gut feeling on the subject. When it comes to building with earth rammed tires my feeling is that it is not a risk I'm willing to take. When we build our home, one of our priorities will be reducing our exposure to toxins. I find the idea of surrounding myself with a material that isn't safe to be used in a garden a bit unsettling. This does not, however, mean that I plan to abandon the use of earth rammed tires completely. I am still planning to experiment with them as a foundation for one of the small structures we plan to build. I will just likely limit this to structures that we will not be spending large amounts of time in, or that will house animals.
I would like to make it clear that I am, in no way, trying to dissuade others from building with earth rammed tires. Since I feel there isn't sufficient evidence to prove either their long term safety, or danger, I would not feel right making a recommendation to anyone else regarding this matter. The intent of this post isn't even to highlight the debate over the safety of earth rammed tires, but is simply my way of explaining my changing views on the subject. I will continue to be interested in Earthship Biotecture, and may very well attend an Earthship workshop in the future if one is ever available in my area.