local sustainable bldg materials and methods?

[dobanion]

from what I read, plain water+concrete+foam air crete is not real strong.

Yes, given. I mentioned as much in some previous posts. The intention here, would be to build up the thickness of the shell to what I want (4" on walls and 2" overhead) with a sprayable aircrete, then immediately cover with reinforcement and followup with a~3/4" thick layer of high psi mortar to tie the reinforcement to the softer aircrete underneath.

Equally possible, substitute styrofoam concrete for the aircrete, which from at least one prominent builder on Youtube suggests is a much better choice. I still wonder where to get a truck load of waste styrofoam on the island. It is not recycled, it just gets heaped in the trash normally. I'd rather not resort to dumpster diving. What are some buisnesses you'd think would produce a shit ton of waste styrofoam on a weekly basis?