Mr. Rawles,
Regarding your discussion of adobe construction – Adobe can be used for structural and exterior construction in a range of climates based on how you make it.
I used to work for a company in Fresno, California that made stabilized adobe – it included a bituminous emulsion (tar-like stuff that’s water proof) to make the bricks water proof. They have been sold across California in residential and commercial construction. Their products included several that were considered structurally sound enough to meet California’s earthquake codes and generally made walls from 12 inches solid to 18 inches (two row with slurry in between) wide.
These bricks did not require any surface treatment to protect them from the climate, but did provide all the benefits of adobe.
Bear in mind, the only real drawback was that bricks ranged from 20 to 48 pounds each! – Steve G.