ICF looks interesting but I have only seen one building using them here. They just tore it down. I would have liked to see how hard that was to do but it was gone in a day. (Commercial property going another way) I have seen a few strange things over the years here. When I was working I inspected a Y-Tong concrete building. It was tilt up construction with all of the walls coming in on a truck. (A kiddie jail). The stuff was so soft I asked if they were worried a kid would tunnel his way out with a spoon. They said they were putting mesh and stucco over it on both sides and hoping the little bastards didn't figure out it was not solid concrete. They built a single family up the street that was foam panels encased in sheet steel. It was put together with a screw gun and angle.