“Many of you might be wondering “Why would I want to mix cob with a tractor?” There are other good methods of mixing cob with your feet, using a tarp, or in a pit that don’t require the burning of fossil fuels. This is true, and any method of mixing cob without heavy machinery is going to be the purest form of cob mixing with the lowest amount of embodied energy.
But if you’re interested in building a cob home in a speedy time-frame then I highly recommend mixing cob with a tractor (or other machine such as a Bobcat or backhoe). Using this method, the cob mixing process will go about one hundred times faster compared to doing it by foot labor. You will spend some fossil fuels in the process, but you will save an extraordinary amount of human labor and time!
I absolutely think it is worth it to mix your cob with a tractor if you are building any size of cob building.” [Definitely use a tractor or backhoe if you tackle a 10,000 sq. ft. house like the Cob Castle.]