Hi everyone. I may be off track a little...sorry, but one bit of information may help. We're also new to Permies and I (Ilene who is Max's wife) will exercise my ability to show my lack of knowledge but desire to learn). Max has done a lot of research on building our own hobbit hole with several methods. What we wanted for sure was a green roof. We recently purchased 34 acres in southern Idaho and learned that in order to do a green roof we need to have any plans signed off by a structural engineer. You may or may not need to have this done but it is causing us grief because we can't locate one who is familiar with green roofs. Still looking. If anyone out there can point us in the right direction we would appreciate it. Good luck in your hobbitous adventure. May your feet be forever hairy.