As usual most anything can be done legally (though not necessarily well) if one pays a lot of money to engineers and contractors.
Here is a relevant HAR DCCA chapter (77) regarding contractors:
Sixty (60!) pages. Starting on page 42 of the PDF is Exhibit A, specialty contractor classifications.
I haven’t tried to look up similar docs for engineer licensing. Too depressing.
In any case it’s obvious that in the alleged state of Hawai’i mere mortals who happen to know how cannot do anything “sustainable” in these domains. Only licensed engineers and contractors can. Legally, that is.
I wonder what percentage of Puna residents have *not* broken at least one of these rules?