Jim Hallock is America’s spokesman for earthen construction. He crafts beautiful and beautifully low-cost buildings with compressed-earth blocks, and teaches the art to students at his facilities in Texas and Mexico. Earthen construction may have no better spokesperson in America: Hallock is passionate about sustainable building and passionate about talking. He has encyclopedic knowledge of soils, clays, stabilizers, block-making machines and the other elements of his trade, and he has a vision of a shining future of cities made of earth.
To help bring about that dream, Hallock founded the Instituto Tierra y Cal on 23 acres outside of San Miguel de Allende, Mexico. There, he and his partners in iCATIS immerse builders from around the world in sustainable construction and farming.
These ancient building techniques may need advocates in the United States, but they are alive and well outside of the US borders, where about half of the world’s buildings are made of earth. Hallock has had his hands in some of those, too. He builds earthquake resistant, sustainable schools, community centers and homes in Haiti, Zambia and Latin America. We asked him five questions.
E4C: What is one thing that people either don’t know, or don’t understand about CEB construction?
JH: What the term “breathable” means, and why it matters. People don’t usually know about the physics of earth and clay as a passive heating and cooling system. Earth has a great ability to absorb and release water vapor. Among building materials, only earth can do it. It helps control heat and humidity in the house. It’s also good for human health. I’ve said it many times: Your skin breathes and your walls should, too. Breathable walls take in toxins. That’s how I got into earth blocks in the first place. I was looking for a healthier house.
E4C: What is one of the promising trends that you see in sustainable construction today?
JH: There’s definitely an increase in interest and awareness of the need to do things differently than we have since the advent of the Industrial Age. We are not pioneers, but rather historians, understanding how, for millennia, people remained comfortable and healthy before we could “plug in.” The explosion of interest in techniques that are truly sustainable is a hopeful sign.
E4C: What has kept you awake at night or has simply worried you about your work?
JH: In the early days… melting walls in Colorado. I didn’t stabilize. I was building for the first three or four years in the 1990s as a purist with unstabilized compressed-earth blocks. I didn’t add lime or Portland cement (ordinary cement) to the mix.
That’s okay sometimes. But I tried it in Colorado, and in Colorado the weathermen don’t know five minutes before a storm front moves in. We’d see the storms coming and we’d scramble to cover the walls with plastic. Literally, that keeps you awake at night. I couldn’t go back to sleep. A big thunderstorm, driving rain, the plastic’s just flapping in the wind and I could hear plop, plop, plop as big chunks of mud are falling off the walls. Now, I’m adamant that people stabilize. Unless it’s just a very special circumstance.
I also worry that I just didn’t pound home the lessons hard enough. You have to teach your practitioners something about soil science so they can get it right. And sometimes they don’t. You’ve got to do the homework first. But it’s worth it.
E4C: Five years from now, what improvements would you like to see in the technology that you and the people you work with use?
JH: Simpler and cheaper block making machines. Same for soil mixers. We can do it by hand, and that’s a beautiful thing, but to serve the mass market that we hope to create, we need faster and cheaper production methods. There’s a thousand machine manufacturers around the world. And there are several good machine manufacturers in the US. But the US is last in acceptance of earth as structure (although improving).
EDIT: Changed last two sentences after a correction from JH.
E4C: The last time we spoke, you were building self-sustained community with earthen construction and sustainable farms in Mexico. Are you and your friends able to weather a future zombie apocalypse on your own, now, or is there still work to do?
JH: We continue to progress, albeit more slowly than I would have hoped. We have housed and fed students on the land for summer workshops. Probably not quite ready for the apocalypse, but getting closer! It’s a beautiful place in so many ways and the dream lives. We have had the good fortune to get some collaborators of significant reputation on board with our vision and that has helped. Still, we are seeking the funding to push it all to the next level more rapidly.
I have also been working sporadically (seven trips of a few weeks each) in a rural community in Haiti since 2009, training people in CEB construction and building a school. It was rough and a slow start but the last two trips – Nov 2011 and Feb 2012 – have literally brought tears to my eyes with the cohesion of our block-making and construction crews. Hard-working believers in the system who became what looked like a masonry orchestra as they moved the walls of a 290 M2 (3,120 sq. ft.) school building up with precision and diligence. It’s all worth it! I am confident that the world will come “back to earth” once the facts are known. I just don’t want it to take too long![ssba]