Would icynene (open-cell spray foam insulation) play well with earthbags?

I would really like to put insulation on the outside of exterior earthbag walls, and Icynene is supposed to be breathable. Does anyone know if one could apply it directly to earthbag walls and then earth-plaster, or even add a paddock-stone facade, over the top?

I would be very cautious of applying it directly to the earth bags. Depending on the solvents in the wet foam (pre cure) and the type of polymer the earth bags are made of, the foam may dissolve the bags. Research both products for compatibility and definitely do a test on a bag that is not part of the structure.

If it is a true open cell foam then once cured you can cover it with most anything. Depending on it's integrity and thickness, it may need reinforcing with chicken wire or the like.