Friday, June 12, 2009

18 things I learned at Day One of the Tierra y Cal Compressed Earth Block Workshop

What a great workshop! Jim Hallock is experienced and entertaining. His interchange with Laurence Jetter the maker of the Cadillac of compressed earth block machines was quite informative and amusing.

Here is a quick look at information that was put out to us the first day. It may be unsupported opinion or not.

1) Jim says white plaster will reflect exponentially more heat than white paint because it is faceted.

2) According to Jim, the best hand press machine is the Auram Press made in Auroville India. (Disclaimer: he holds the rights to distribution in the USA.)

3) Compressed earth block can handle much more clay than poured adobe can, therefore it is much more efficient at absorbing and releasing water vapor.

4) Jim says every building gets wet eventually, and with a life span of 2000 years every CEB building will definitely get wet, so use lime stabilized blocks.

5) The production of quicklime and hydrated lime puts CO2 into the atmosphere but when it is used to stabilize the blocks it takes CO2 back out of the atmosphere as it turns into limestone.

5) Crushed limestone won't do a darned thing in your block to stabilize it.

6) Soil for compressed earth blocks should come from below the agricultural top soil.

7) Dr. Charles Graham at Texas A&M has taken an interest in compressed earth block and has been a boost to its use.

8) The slurry that connects blocks actually is absorbed into the block. A proper slurry on a block will harden without cracks and when removed from the block you will see an indentation in the block,

9) There is a 40 to 45% reduction in volume between prepared dirt and the finished block.

10) By transportation regulations you can truck much more prepared earth for blocks than you can finished blocks. A dump truck can carry the soil, but the number of finished blocks you can carry on a flatbed 18 wheeler is severely limited.

11) There is a lot of preparation of soil needed to turn it into blocks. One of the biggest problems is drying it out. The more clay you have the drier your mix needs to be.

12) Over 100 companies make compressed earth block machines. Ital Mexicana makes an excellent one, especially if you are making blocks in a factory setting.

13) Chicken wire can make really great earthquake stabilization, though there are many other methods and local regulations apply.

14) Ital Mexicanan sells villages on building and sells the machine which they hold in common.

15) Adding Sisal to plaster also helps provide earthquake protection.

16) The AECT machines have a device called the Hallock Stop, which Jetter devised after repeated pestering by Jim Hallock of Tierra y Cal.

17) Hallock's pejorative name for stick-built construction "kindling built", since it is all just kindling for the big fire.

18) Curing benefits both stabilized and unstabilized blocks. According to Laurence Jetter they seem to cure better when wrapped in stretch wrap on a pallet than when left out unwrapped.

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