Sun, November 14, 2010: Detailed description and photo series of the construction phase and interiors
This clay mud dome was built in Atacama in Chile and built a permanent clay mud geodesic dome:
The dome is based on the geodesic approach, icosahedron based with 4v frequency and 5.5m diameter.
The main structure is made with 2"x2" pine, with a flat pipe attached to the ends, so a hubless approach, the pipes are 1" in diameter and 1mm thick, and 5cm (2") into the wood, fixed with a self drilling screw.
The dome has two covers: inner cover with a material called here "cholguan", very common (it's made of wood fibers, then pressed and cooked in an oven), some people call it wood cardboard.
It's fixed to the struts with apprx. 4000 clamps, exterior cover is clay (mud) with straw on a coop net base, between this two materials I put sawdust to give some isolation.
The purpose was a mix of old building technics with a dome and make it cheap.
The ground is made of concrete with a mosaic of ceramic waste.
Rain Insulation & Leaks
Regarding leak there is no big problem because it rains very little, in case it rains we solve by covering the dome with a plastic cover for the few days in the year to avoid the leaking and most important to protect the clay mud.
The inner climate of the dome is nice in winter (8C exterior) but it requires a heat source to raise the temperature. In summer (30C exterior) it's very cool inside (it has 4 triangulated windows and 1 little air extractor on top).
When the door and windows are open at the same time the air circulates from the door to the windows exchanging the air very quickly.
Regarding insects: some moths get in because they attracted by the light.
Before I covered the dome I installed electricity with PVC electrical conduit, two separete circuits, one for lights and extractor and one for plug electrical devices.
I learned that it's very difficult to put the mud using the very structure of the dome to support the person, so I had to use some scaffolds.
The facets (speaking of one type) are slightly different to each other so I had to cut an average size to fit it all.
The thickness of the clay mud cover is apprx. 1cm, I calculated based in some samples that the total weight of the dry mud are 2t (2000kg).
One of the reasons I used mud is that the mud and the pine wood have very similar thermal expansion coefficients (experience in other type of construction with mud and steel are not good, the mud cracks and falls to the ground because the very different thermal expansion coefficient of mud and steel).
Things Learned & To Do Better
The things I plan to do next time are: an electrical circuit to connect built-in speakers (for music) and an alternate electrical circuit for solar panels (PV panels).
The clay mud had too much debri and its neccessary to sieve more than I did.