It’s difficult for me to say something about the video you saw. It’s a documentary of Julien Donada about Claude&Joël Unal’s bubble house. This documentary was on Arte channel in 2015. On my point of view it’s one of the most beautiful doc of Unal’s house but also in this type of architecture. There is nothing to add.
Des conseils, idées, techniques sur la construction d'une maison bulle bioclimatique enterrée.
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To add is possibly, that Joel Unal has worked 48 years or so on that house, and it is said, that he isn’t living inside the house not longer because it is a little bit to difficult for him to live there. The fact that always in a rhythm of 8 years the house is to paint looks like a disadvantage.