Tough-as-Nails Interior Design / Building an interior tornado/storm shelter is easiest during new construction. No matter what type of construction materials are used, the unit must be bolted to a concrete slab. The cost to build an interior storm shelter is $6,000 to $15,000, depending on the size, location, and door style.
Safe rooms not only provide protection for the homeowner from intruders, they offer shelter from tornadoes and other high-wind storms. If a basement is not available, build the above ground safe room and use it as a walk-in closet. Your guests may never know the difference.