We are testing the earth materials that we have been gathering to build our house in the spring. It’s great to experiment now, rather than on the house we are building. We were looking for a project to test our sand/clay and straw mix, so we decided to build a picnic bench and earthen floor under the greenhouse cover. To minimize the amount of cob used to build the tables, we used rammed earth tires. (Earthship Style) and even used some recycled cans to fill spaces as they do in earthships… It takes about 1 full wheelbarrow load of dirt to pack a 225/75/15 tire. Pack the dirt in tight with a hammer and you have about a 350 pound thermal mass. We were calling it Thermal Mass Furniture. So we have about 4200 pounds of rammed earth tires surrounded by 1500 pounds of Cob. The bench is sitting right in front of south facing wall.This will be a nice heat sync for the greenhouse space. It will retain a large amount of heat from the sun in the day and give it off at night when the air cools down inside the greenhouse.
We got some help from our neighbors and our friend Spencer. Thanks guys. Spencer showed up this past Sunday to help mix up a batch of cob with the bobcat and add to the Tire/ Earth / Wood Table and bench that we are building. Lots of work for sure but a great way to get in shape.
In the photos you can see the progress of our Greenhouse and Cob building.
The bobcat is a great way to mix the material. It also is very handy for delivering the cob once mixed. A full bucket of cob will tip the bobcat. That’s is over 850 pounds. So this is a great way to speed up the process of building with cob.
We also decided to try an earthen floor mix. It was mixed a little bit dryer than the cob we used for building. We also used less straw in the cob mix.