 Safe rooms in the basement or on a concrete slab can be built with concrete walls, a building technique that is normally not possible on the upper floors of wood-framed structures unless there is significant structural reinforcement to the building.The U.S. State Department often uses steel grillwork much like a jail to seal off parts of a home used by U.S. Foreign Service members overseas when they are living in cities with a high crime threat.In some cities, the entire upstairs area is grilled off, as well as every window and door to the home.