A couple of days ago this was posted on our bulletin board:

“Greetings Earth-builder Aficionados,
You’ll be glad to hear that I have invented patent-pending technology to make prefab earth walls, which I sincerely believe will revolutionize our built environment from production to construction to operation. As I’m sure you all know, earth is the most eco-friendly building material, but earth building is very labor-intensive and thus, quite expensive in the Western World. But not for long, because my prefab earth walls are made by a machine; I significantly lower the production cost and because these walls are cured, lime-washed and/or waterproof, you can quickly and efficiently construct a building. In fact a small one-story house could be built in a couple of days. And guess what? I just did it. Check out my website: http://www.ecoearthwalz.com to learn more about my prefab earth walls and the world’s first prefab earth shack. We are still prettying up the dirt shack and we are currently installing a dirt floor. See our blogs for further details. Last but not least, these prefab earth structures will also save big bucks on operating costs, as earth walls passively regulate temperature and humidity and they are mold-free. BTW, I purposefully made my technology to be low-energy and hope to power the entire operation with solar PV power. I don’t think you can make a more eco-friendly product than this. I am looking to bring this product to market and expand operations. Please let me know if you have any interest. My email: infoATecoearthwalz.com”

According the the website, “Ecoearthwalz prefab earth walls are made from natural dirt/earth (sub-soil) and mixed with a little water.  That’s it! The mixed dirt/earth is fed into our newly invented automated technology to produce earth walls of almost any size and shape of up to 2 feet thick, 6.7 feet long and 10 feet high. Once suitable foundation and stem walls are in place at site, Ecoearthwalz prefab earth walls are delivered to site and installed.” Furthermore, they say that, “Earth walls have excellent thermal mass which help to passively regulate internal temperature and humidity reducing use of mechanical heating and cooling – lowering utility bills!”

My reaction to this is not entirely positive. I applaud the use of natural soil for building structures, as can be done with rammed earth, cob, adobe, and earthbags. But unlike these simple methods, this concept requires significant machinery that is located somewhere other than the building site. Then, these massively heavy and fragile walls must be somehow trucked to the building site, unloaded and assembled using more heavy equipment. This can only be considered ecological if the manufacturing plant is very close to where the building will be placed. Otherwise the embodied energy would be significantly more than if the walls were created at the site.

I also question whether such large compressed earth walls without any stabilizer in the mix or internal reinforcement can be sufficiently robust to withstand the transport and assembly process.

One last observation is that while what is said about the thermal properties of earthen walls is true in terms of thermal mass, this does not generally equate to greater energy efficiency. This is only true in those rare climates where the extremes of heat and cold are minimal. Otherwise, a solid thermal mass wall will bleed energy much of the time, rendering the interior space either too cold or too hot. This can be mitigated by creating an insulating envelope around the outside of the building, then such heavy mass walls can contribute to great energy efficiency.

I am curious what other readers feel about all of this… please leave a comment.


Comments

Prefabricated Earthen Walls — 5 Comments

  1. I completely agree that shipping pre-fab earthen walls does not make sense — it almost sounds like a parody of eco-building. The beauty of earthen building is that the dirt is right there!

    At this moment (yesterday & today) we are digging a big ditch for a partially submerged greenhouse. One of the great side benefits is that we now have 130 cubic yards of dirt, for our spring house build! We will be using earthen plaster inside and out, and earthen floors. Our dirt is very sandy, but this dig hit a sizable clay layer– couldn’t be happier!

  2. Perhaps the company could make the manufacturing process mobile and make the walls on site. I think everyone would profit from that approach. I would not like to pay for shipping a rammed earth house anywhere.

  3. I totally agree with you. The embodied energy required for transport and assembly would be very high compared to building on site. And with the soil not stabilized I would think cracking could be an issue in transport and set-up. And thank you, thank you, thank you for pointing out that high thermal mass BY ITSELF is a poor choice for most climates! I’ve seen so much misinformation on this point and people just starting out don’t realize the difference between thermal mass and insulation, at least not in relation to different climates, and when it’s okay to use alone.

  4. How do you install electrical and plumbing doors and windows looks like more work than there worth and what’s the cost not practical for remote areas

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