Muddy gringos
11 July 2006
A note on the photos on this page: if you click any photo, you will go to a larger view of the image in the Parras 2006 online gallery, where you can check out other photos. Unfortunately, there are very few photos of me, because I have posted most of the photos we have in our group’s gallery. I’m working on changing this.
I keep getting more and more behind on my blog posts, but I want to get it all in, so I’ll need to step it up a bit. After our program visited General Zepeta, we began a natural building unit, which meant getting out of our classroom and getting covered in the muddy clay substance which is used to make adobe bricks. By the end of the unit, everyone had blisters on their hands. Many had hurt their feet, and were feeling glad for getting their tetanus booster shots before they came. Even though it was hot and exhausting at the time, now everyone misses building adobe bricks.
To make adobe, you start with a wet mixture of sand and clay. It was unnecessary for us to mix sand and clay because the soil which was delivered had a lot of clay in it already. We let our mixtures sit overnight in a Mount Saint Helen-shaped mound, the crater filled with water, so that the clumps would dissolve. The next day, we mixed the material with our feet, and added in paja, or straw, which provides the tensile strength to hold the large adobe bricks together as one unit when they are dry. It’s not 100% necessary in areas like Coahuila, where there is little seismic activity, but still a good idea. The completely mixed substance is then “cut” using hoes, which chops up whatever dry clumps might still be in the mixture, and pulled away from the pile to be loaded into wheelbarrows to be hauled away and made into bricks.
The forms used to make Adobe are called adoberas. They are filled with the adobe “dough,” as I’ll call it here, which is pounded and kneaded in so that it fills all the corners without structurally-unsound air pockets. If the adobera is wet and clean when the material is put in it, it will lift right off after all the material has been placed in it, kneaded, and the top has been smoothed off. What is left is a wet adobe brick in the shape of a brownie, about four inches tall by one foot wide by one and a half feet long, which will dry in a few days. For the structure we were aiming to build, which, unfortunately, will not be seen through to completion while we are here, 1,400 of these very large and heavy bricks are necessary. We were able to make about 1,000 bricks. The remaining will be purchased from an adobe brick maker.
One of the reasons Adobe is an appropriate technology is because of its thermal properties. The old houses here are exceptionally cool and comfortable during the day, without air conditioning, because the Adobe bricks slowly absorb and hold heat throughout the day, heat which would be making the interior of the home uncomfortable if it wasn’t held by the adobe bricks. By the evening, the adobe walls will have absorbed a significant amount of heat. As the air cools, the opposite heat exchange that occurred during the day will occur, and the adobe bricks will cool as they let off the heat they absorbed during the day, warming the interior of the house during the cool night. Recognizing the utility of these thermal properties requires taking a different approach than is conventionally taken in U.S. building codes, which recognize only insulative material. Adobe, since it transfers and absorbs heat, is not insulation, but thermal mass. Even in Mexico, where adobe had been a popular building material for a long time, it is not impossible to get a bank loan to build an adobe structure. As to why this limitation is in place, I am not sure.
Another reason Adobe is an appropriate technology here is because the materials for it are all locally available and so they don’t need to be imported using fossil-fuel powered transportation. Also, making adobe employs local people. Frequently, appropriate technology implementations are less expensive in terms of materials, but require more labor, and adobe exemplifies this. The adobe bricks are labor-intensive to build, but require inexpensive materials. Especially because of the availability of inexpensive local labor, adobe seems especially feasible and appropriate here. For more on adobe, check out the adobe category on Appropedia, the site our AT program is using as it’s main information platform.
This point about appropriate technology and its high labor need is an interesting and necessary discussion. I admit I am obsessed with efficiency, not only in my own life, when I will confess I have read at least one of those books with someone wearing a suit on the cover telling you how to squeeze more out of your time (it’s really quite good, Getting Things Done, by Greg Allen, a business productivity expert who emphasizes “mindfulness,” a persuit he borrowed from eastern traditions). I will become instantly frustrated and critical if I work with any organization which I think is running inefficiently, and employs too many people and is therefore wasting public money or overcharging their customers because of high staff overhead. This is a distinctly American mentality, which I refuse to give up. At the same time I understand the occasional value of labor over automation, which is such an important reoccurring theme with appropriate tech, and it has instructed my behavior as a consumer for a long time now. When I purchase more expensive organic food, for example, I assume that the food is more expensive because of the higher labor overhead, which is necessary because the “less efficient” farm doesn’t use the same petrochemicals which allow modern farms to get higher yields per farmer. However, I assume (I hope correctly) that the organic products I buy not create more safe jobs for farmers, but also are higher quality. Too often, efficiency comes at the expense of quality in the American economy.
One of my favorite examples of appropriate technology is from our teacher Lonny. He compares Blackboard with Moodle, two online learning management systems HSU uses. Blackboard, an expensive commercial product is being phased out in favor of Moodle, a free “open source” solution. The thing is that Moodle isn’t really free, because it requires a lot of technical staff to run it, whereas Blackboard comes with service and support from company. He estimates that the two solutions actually cost the same but posits that Moodle is more appropriate because running it and refining employs local people and builds our local pool of technical expertise and local economy. Since HSU can build their own refinements onto Moodle, and borrow the open source refinements of others, we end up with a higher quality service.
aaron :: Jul.11.2006 :: México ::