I've seen several houses made with steel studs. In fact I wired several a few years ago. They had poured cement foundation and then used heavy guaged steel frame studs for the exterior walls and a lighter guaged stud for the interior walls. Then used wooden truses for the roof. My question is can you use the heavy guage steel studs for floor rafters in a block foundation? I'm thinking of having steel studs for floor rafters. Then plywood on top of that, then steel studs for the exterior walls. Expensive maybe! But wouldn't have to worry about termites and slugs as much.