Earth: The Thoroughly Modern Material
An adobe by definition is a mud mixture consisting of clay and aggregate usually with straw added, that is cast in a form and allowed to dry. When ready to be placed in the wall, an adobe block, depending on the size, which varies from tradition to tradition, will weigh in the vicinity of 40 pounds.
Those of us who advocate for the conservation of historic earthen buildings, and promote the use of earthen materials in new construction do so by pointing to the durability, longevity, beauty and friendliness of mud. But when we talk about the economics of earthen building we sometimes come face to face with an irritating paradox; how in the developed world can 40 pounds of local soil, less than a third of a cubic foot, cost up to $2.50 by the time it is in the wall? We know the answer - the material costs nothing, it's the labor that's expensive -- but the answer doesn't help us make our case. Even in the developing world earth is looked upon, again paradoxically, as a thoroughly outdated mode of building that is too expensive. Time, after all is money, no matter where you are or what you do for a living.
I am not too concerned with the developed world. The price of Santa Fe style homes is of little interest to me, just (apparently) as it is of little importance to the folks who buy them. I am very interested in how earth plays out in other settings, including post-disaster rebuilding, and mass housing schemes for low income families. It is in these settings that the irony of earth being rejected because it is too time-consuming, too expensive or not modern enough becomes a truly sad incongruity. In the days immediately following the earthquakes in El Salvador I received two calls from aid agencies seeking advice and possibly assistance. My response was that they should think in terms of local labor and local resources in the rebuilding initiative, but not make the mistake of thinking that un-housed people have time on their hands. Shelter, after all, is only one of several pressing concerns they have to deal with.
I suggested investing in a portable sawmill (two recently sold on eBay for less than $5,000) and in a pressed earthen block machine (about $30,000, new). Then field a crew who both build and train. Engage local labor, but pay them according to the local economy, and save your money by avoiding expensive and inappropriate materials like Portland cement, corrugated steel roofing, and fired brick. My experience with both sawmill and block machine is that they are efficient, fast, user friendly and unbelievably economical. Paying the local wage scale in a not-for-profit setting I have seen lumber produced for five-cents a board foot, and earth block for six-cents apiece -- in the wall. Using the equipment with inexperienced labor I have many times built a shell of a house in one day.
There were two areas of resistance to the idea. (Interestingly, seismic resistance was not one of them -- it is now easily demonstrable how aseismic eathen buildings can be, as I have indicated in a previous column.) The first argument was that the initial investment was too high. Odd that the investment would seem high given the speed with which houses can be constructed at an extraordinarily low unit cost using local resources. In my experience, false economies tend to be generated by project planners who don't have hands-on experience in the field, don't understand the logistical efforts that make a program work, or simply lack either the resources or the will power to make things go. The economy argument may also have been a bit of smokescreen that covered the other issue -- that saw mills and hydraulic presses are not "traditional" in the romantic sense. It was encouraging that aid agencies were interested in adobe to begin with, but interest waned when earth was cast as a "modern" material.
Traditions are embedded in communities, but are never static and always change according to need and contingent circumstance. Witness the "traditional" pitched metal roofs that replaced the flat earthen ones on New Mexico's adobe churches in the last fifty years. In the case of El Salvador there is a tradition of earthen architecture, and there is an immediate need for lots of good houses fast. Can tradition in this case accommodate need? There is no reason why it cannot, but I am afraid that the question will be framed as a dilemma and the outcome will be a retreat to mediocrity -- houses will be rebuilt with concrete and steel, not because it makes sense but, at least in part, because of an entrenched resistance to seeing the local tradition of earthen construction advance to its next technological level.
The most important issue is, or course, acceptance of the new technology by constituencies. They typically want modern materials for lots of reasons, but mostly it's the image thing. Can earth fill that need as well? Or, is the promotion of earth (because it makes sense to us) as paternalistic as its rejection by someone else if the process tweaks local custom? There is that danger and we must be wary. I have lost the earth argument in some settings, and won it in others. In Nigeria the argument was won because it made economic and social sense to both the service provider (the government) and the constituency. Earthen blocks coming from a machine are, in this case, viewed as thoroughly modern. The bonus is that local architectural forms seem to follow the use of local resources.
After years and years of working in community development settings in many parts of the world, and having used architectural conservation as a vehicle for achieving cooperation and community cohesiveness, I believe unequivocally that the technology of earthen building is well understood, well defined in local contexts, and able to be refined to meet present needs. Understanding and manipulating the technology on a local level is a no-brainer. The obstacles are the twin battlements of false economy and the patronizing notion that if buildings are quaint, the way they are built should be, too. That line of thinking leads to the loss of the tradition altogether as imported materials displace local ones. The social services and aid providers may have fallen into a similar trap as those presrvationists who argue that the conservation of materials trumps process and function.