Superadobe Is Like Working With Playdough

Quick update on dome build status, but first check out the flowering prickly pear cactus near the dome that has yellow, orange, and pink blooms all on the same plant! When we built a dome last year I kind of waited until we were pretty much done and then did a reveal. This time I'm going to provide updates along the way for those interested in seeing how it's done. 

In older posts on healthy building I also explained more about why we chose Superadobe - with additional information if you want to learn more. If you look at last week's post, you can compare and see how much we've gotten done up to today - working on it very part time.
The girls each have one foot on a ventilation pipe. The pipes are tilted down so rainwater flows out. They will get a screen on the outside to keep bugs out and the inside will have a cover to easily control how much airflow you want. Half the door form is in place. The top half is in the background.
Now you might be able to tell that the pipes are covered with another course. The door form is fully in place. You can see the barbed wire that is laid between courses to add tensile strength. The pieces of metal laying on top at the buttress corners are there to stop bags from getting caught up in the barbed wire at each end until we massage it the way we want it. We cut the length of bag material we need and then shimmy it over the funnel that is sitting on top on the left. You simply tuck the bag underneath itself on the ends and its own weight holds it in place.
Here you can see the bag end tucked under itself over the piece of metal. Doesn’t the door form look kind of like a rocket ready to take off? You can also see the funnel in use. It makes it all super easy. One can of adobe mix at a time is dumped in. The girls usually do that and it goes pretty quick. I hold the funnel, which makes me feel lazy as the girls are running back and forth. But they don’t like my job because it can require some strength to wrestle with a bag full of dirt on occasion, plus laying the upper courses may be scary if you don’t like heights.
What you see me doing there is using a common plumber’s tamper. This results in “rammed earth.” Another way to build with earth is with rammed earth blocks, but it does require more specialized equipment. The bags are just there to hold the adobe mix in place for tamping and drying/hardening. I use the tamper along with bricks and rocks to massage the filled bags however I want. Kind of like sculpting, or playdough. In the foreground is part of the tarp uncovered showing some of our adobe mix that will go in the buttress bags. Mixing is the most labor-intensive part of building. We mix batches of lime, native dirt, and water in correct ratios in a wheelbarrow and dump them on a tarp that doubles over the top to keep it moist while we mix all the batches. Each batch is maybe 1/3 of a wheelbarrow and we made 12 batches for today’s course.
After laying a course we cover it to keep it moist longer. If it dries too quickly, it cracks. That won’t ruin it when everything is together as a whole, but cracks won’t strengthen it either. The tarp also protects the bags from the intense sun that will make them deteriorate faster. Again, once everything is together and the adobe is set up, it will all hold together without the bags, but they add strength in the meantime. We also need to tarp it when building during monsoons so none of the fresh, soft mix gets washed away. The mesquite trees in the background will get pruned and trained up for a nice shade canopy.

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2 thoughts on “Superadobe Is Like Working With Playdough”

  1. Pingback: Finished Dome Build Report – Sabbatical Ranch

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