Even if your roof and doors don't give way in a tornado or hurricane, powerful winds are going to push against your walls directly -- and possibly slam big pieces of debris into them at 200 miles (321 kilometers) per hour. So if you want a storm-resistant house, you've got to have tough walls as well.
Fortunately, back in the late 1960s, an inventor named Werner Gregori developed a new technology: insulating concrete forms, or ICF, that use polystyrene forms which clamp together in tongue-and-groove fashion, with plastic or steel connectors [source: ICF Builder]. Try to imagine really big, tough Lego blocks, and you'll get the general idea. Once the building blocks are set, a steel framework is put in to for reinforcement, and concrete is poured into the plastic forms. The result is an airtight, insulated, fire-resistant 2-foot (61-centimeter) thick wall that's sturdy enough to withstand strong winds [source: DeMatto].
One such tornado-wall system, the ARXX ICF wall, is designed to withstand objects propelled by a 250-mile-per-hour (402 kilometer-per-hour) wind [source: ARXX].
ARXX claims that using ICF technology isn't that much more expensive than using conventional wood and mortar and that it actually will reduce your heating and cooling costs drastically, because an ICF building typically uses 44 percent less energy to heat and 32 percent less to cool [source: DeMatto].