All great ideas. The rafters/crossbeams are good and if there is one made of steel beam that can fit a weapon inside the beam even better since the beam is made of steel it is hard to find with a metal detector. I say anywhere that has metal framing is very good. So if your house has metal studs and not wood then you can put a weapon in a metal stud and then it is very hard to find. You plaster the wall and only you know were the weapon is.