The music is blaring, the laughs are abundant, and the Cobb cha cha is in full effect! There is nothing like the feeling of a group of neighbors coming together to co-create something that will benefit the land and its people. Have you ever heard that term “It takes a village”? I truly believe this quote is tremendously relevant to many situations today. Anything from raising your children, to building your house. It is way more enjoyable and efficient, if a whole community comes together to accomplish something that is directly contributing to the village. Its a total win win.
Before it needed to take a village, I needed to asses the situation of this unfinished Cobb oven project I was planning to take on.
There appeared to be some masonry work with local stones. The motor was concrete. That was a little weird to me. The technique I know has no concrete, just clay, sand, straw and stones. So this was something I had to navigate. On top of this concrete stone base was six inches of cob that formed a ring around a sand circle that held the fire brick oven floor.
Communities around the globe know this site all too well.
That might not sound like such a big deal at first, but in a Ecovillage setting, it can be progressions black plague.
They seem like great people, no malicious intent what so ever. They either failed to account the time factor for the completion of the task they were in charge of, they were slacking, or many other reasons. Which is cool. Ideally next time they will think twice before biting off more than they can chew.
When all that is said and done, the village is left with this uncompleted project that they now have to delegate and expend resources on. It can be highly unfortunate when these unfinished projects increase in number. They pile up and began to put the community in a never ending “catch up” phase. This in severe cases can cause a massive blow to the moral of the community members. A worse case scenario would be the members leaving the community.
Moral of the story….. think before you commit.
Back to the Cobb Oven…. There it was. I was going to build a Cobb Oven on top of a preexisting stone and concrete base. I have never done this before, but I feel I am competent enough to take on the task. Here we go, time to analyze!
Okay, the whole reason they put on this Cobb ring on top of the base was to replicate a center full of sand for the fire brick oven floor be leveled in. In the technique I know that I got from the lovely Sigi Koko, requires you to build a hollow base made of stone and Cobb. Basically a cylinder standing upright. Fill it with non-compressible material like tamped gravel, with four inches of sand heaping passed the top. The sand will help level your bricks flush with one another.
This Cobb ring has got to go. Even the fire bricks were molded with the Cobb at the corners. It is totally compressible material. It will weather and crack, most often where the Cobb meets the concrete causing foundation issues.
Why not build a concrete sand box and scratch up the outside so that it can adhere to the Cobb from the Oven. In doing this I will have a strong reliable base that conforms with the preexisting concrete base, and it will provide a surface that will have what it takes to bond with Cobb.
Within the course of a day I built a frame and was filling up my home made concrete sandbox so that I could start leveling my bricks for the oven floor when the Portland cement dried.
Then Wha La! I was ready to make my sand dome on top of the bricks to serve as the interior of the oven.
After the sand dome was completed, it was time for the fun part!
Making the Cobb!
Here we go! The Creation of the oldest building material known to man, the Earth itself.
The biggest resource needed in natural building is Human Power. At the end of a naturally built project, I believe the biggest expense is labor. If a future home owner wants their home constructed naturally, but they are unwilling to contribute their own sweat equity, they better be prepared to pay for the labor.
Which bring it back to “it takes a village”.
One part Clay(that was sourced a half a mile up the road and sifted here) and three parts sand on at least an eight by ten tarp. Starting with a dry mix first, mixing it thoroughly. Building up the dry mix into a mountain followed by smashing the top into a volcano. I add the water in the bowl molded sand hill. Only enough water so that it can be cover with sand with out running off.
Then comes the fun.
I launch myself skyward, I slam down onto the partially wet dry mix with my bare feet. This is the traditional way of making Cobb. Made with the feet, one step at a time, flattening the volcano filled with water then rolling the large Cobb pancake by grabbing the tarp while standing on the mixture. Pull the tarp back, causing the Cobb to roll over itself into a Cobb burrito. Repeat the process at one end of the burrito to make a lumpy sphere.
In whatever way you can imagine. I like to dance and Jump around. Make it fun. I want to be doing things because I want to, not because I have to. Make this play, not work.
Since we were making four inches of thermal mass layer first I wanted it to be a cream cheese consistency. Better it to be a little dry than a little wet. If its too wet it tends to sag when applying the mixture, but if its a little on the dry side you can just wet each handful and work the moisture into the Cobb.
Keeping our hand slightly wet, we slap the finished mixture onto the sand hill that makes up the interior of the oven. We put soaked newspaper around the sand hill so that we know when the sand ends and the clay begins when digging out the sand later to let dry.
Putting pressure downward and from the side, we applied the four inches of Cobb Thermal Layer with no straw, not worrying about making a door(it will be carved out later). Sculpting hand sized balls of Cobb and molding it to the newspaper sand hill starting from the bottom up. With the help of two others it went up in a day.
We scratched up the surface of the thermal mass to give it “teeth” so that it could adhere properly when letting it set over night.
Coming back the next day, we wet it down to moisten it up for the next six inches of insulation. This layer is fifty percent clay/sand with tons of straw. We mix the dry clay and sand first then wet it down and mix like the initial layer. When the mixture is a milkshake consistency you add the tons of straw, but work it in little by little. Its should look like clay covered straw.
Once that was completed I soaked the thermal mass and began to apply the thick insulation layer. This is where I molding the door way. It needed to be two thirds and high as the interior of the oven. I then cut the thermal mass to the newspaper with a trowel. Working the clay covered straw six inches thick, it too was completed in a day with the same help.
I took out one third of the sand and poked my fingers into the surface of the insulation layer to create lumpy teeth for the final layer. Now it was time for us to let it dry for the next seven days.
Clean up began as we prepared to wait about seven days for the incomplete oven to dry.
A few days into waiting for it to dry, Don told me he would be going to Tucson for the weekend and come back Sunday. This would be a great opportunity for me to do some ground work and network with all the sustainable development within the Metropolis.
I smell an adventure coming. Who knows what opportunities will be revealed in Tuscon. I hear many great things about the area. I hope to navigate it well!
Stay tuned for my Tuscon experience!