Thank you all for your input on this subject. More than likely in the regions of the world we are looking at sending this structure materials for making even a crude concrete mixture are available (we send portland cement with the mission teams).
The structure is a simple single slope roof. We are considering using ICF forms for the exterior walls of a single family house to be built on a mission trip to nicarauga later this year.
Is it possible to use sand or earth to fill the cavities in ICF forms in lieu of concrete for the construction of a simple single story building? I am assuming we could devise a way to keep the sand/earth in the forsm without leaking (vapor barrier?). Thnk you.