The Project: To build a coop for 6 chickens and 2 pygmy goats using the rammed earth style construction. The structure is 17' in diameter and 15' high, it's inner walls are created with rammed earth in 128 used automobile tires, scavenged from local tire shops. The thickness and mass the wall holds allow for a controlled inner climate through the seasons without the use of electricity. The roof funnels rain into an internal spout that leads carbon filtered water to the livestock. The coop has two 1'x4' windows placed to catch more sun during the winter and less during the summer. There is a pop door and three upper vents to help air circulation.
-Breaking ground. Tough, dry, rock ground. Two people, two pick axes and a lot of hours. We came to find out the surface was far from level. Using a high tech steak-string-level method we determined that from one edge of the structure to the other nearly sank one full tire. In this picture you can see the near side of the tire stack is dug out and placed below ground level. We found the perimeter of the structure by using a round steak in the center attaching some speaker wire with a steak to draw at the other end.
-Ram that earth! With each completed tire came a lot of dirt and a lot of swinging a sledge hammer. The center steak had to be replaced with a taller one as to stay on the target perimeter with each tire placed. You can see the cardboard used under a tire as it is packed so the dirt doesn't continually fall out. Using a long level, we checked the top of three tires at a time to stay as level as possible. Sometimes it required selecting a wider tire, or just packing a tire extra tight. It would be ideal to only use one size tire.
-Gringo blocks, the blocks of scrap wood to fill the void at the start and finish of the wall. As the wall grew so did the difficulty. We did not consider the awkwardness of packing a tire full of dirt with a sledge hammer as it got taller, this is when we learned how to pack while standing on top. The pop door was framed in at this point (seen in the back at the far side of the coop).
The rough door framing was added here along with the window frames (seen on the left side). We also started to leave space for the vents.
The Roof - Built with an internal rebar skeleton using six 20' poles each bent in 5 sections to create a dome like shape. The rebar was bent by sticking it into a steal beam that just happened to have the right size hole, then walking to a designated spot for the right amount of flex. Although this method produced varied results and is not recommended if you want a complete symmetrical roof, it was cheap and got the got the job done.
Once bent, the ends were inserted into the center of a tire, the dirt around it dug out and concrete poured to create anchor points. A few 20' poles were bent in half circles and crowned on top of the dome skeleton at different elevations. Rebar tie was used everywhere possible to give as much strength as possible. Once the skeleton was complete and anchored in, it started to become very sturdy. Later we added scrap rebar to diminish the large gaps, this would later help the concrete application.
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| Looking up from inside at rebar skeleton. |
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| Showing rebar skeleton after the first stage of roof shell goes up. |
At this point, wire mesh was attached to the under side of the roof. This was to allow the concrete that would be placed on top to bond to the rebar. This was a tedious task, I climbed on top and below on a ladder my friend would push though wire ties so I could secure them to the rebar.
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| On top looking down into the center of the coop. Showing concrete placed on top of the mesh. |
The mesh is on and the roof goes up a few inches at a time. The can and glass-bottle-brick section of the roof was only intended to go up this high. After that, when the roof started to bend in toward the center, it would be concrete on mesh only. This was to speed up the application process and make the top of the roof lighter, and stronger, hopefully lasting through more seasons. The outer wall starts to get covered at this point.
The roof is complete and the exterior walls continue to be built. Chicken wire was attached to the tires and stuffed with bottles and cans. This segment of the construction became a bit difficult as the concrete wanted to make a plunge from its vertical surface, because of this we switched to using a more efficient concrete.
Now the coops exterior walls are complete, and a layer of paint is applied. And in came the snow!
It is the awkward stage, no doors or windows, the paint was applied but sections cracked off with some concrete. The failing concrete sections were due to the change in temperature and switching concrete types. There was an effort made to smooth out the overall shape of the roof by adding more concrete in the dips.
The final stage. Doors, windows, vents, plumbing, a second coat of paint and even some plants in front. The door and window frames are made out of cedar to help with Washington's wet climate.
Here are a few random pictures...
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| Making glass-bottle-bricks the safe and efficient way using a modified wet tile saw. No nay sayers! |
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| Simple CAD elevations. |
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| Inside looking out just as the last stages of the roof were added. |
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| Exterior view of completed windows. |
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| Internal plumbing, the pipe on the right carries roof rain runoff. The pipe on the left is a drain pipe. The idea here is to either allow the rain water to continually flow through the pipes and drain, or by turning the red valve and opening the faucet, allow the water to collect in a drinking container that has a overflow tube leading back to the drain pipe (not currently shown). |
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| Pop Door - Able to open from the outside and also has a latch on the inside for added protection. |
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| Showing the front door. |
