Hardening Your Home Against Tornadoes



The very worst tornadoes, such as the one that ripped through Moore, Okla., might overpower even our best home construction techniques. But there are plenty of steps to take to protect you home against more common kinds of twisters, and a variety of shelters to protect your family from the worst-case scenario.

Hardening Your Home Against Tornadoes - Popular Mechanics

June 4, 2013 2:44 PM


When you think of a tornado, you rightly think that there's little you can do to protect yourself short of huddling in a fortified underground bunker. Yet in the case of an F4 or F5 tornado, a fortified underground shelter would be the best bet.

Still, underground shelters have their own set of problems, including the possibility that groundwater can seep in or that they can easily become moldy as condensation forms on their walls. They're also extremely expensive and notoriously unstable—and expansive soils in the southern U.S. can wreak havoc with them.

Instead, existing homes can be fortified with sheet metal, plywood, and heavy-duty hardware, and you don't even have to go to an architect or an engineer for plans. FEMA has some surprisingly straightforward plans (PDF) that an experienced amateur builder should be able to use to make a safe room in his or her house or basement. And it doesn't require exotic hardware to make high-strength connections to bolster a residential frame building. Chances are you can find most of what you need at a local home center or lumberyard.

One of the best names in the business, Simpson Strong-Tie, makes connectors that create a continuous load path, tying the house together from roof to foundation. Simpson has teamed up with university engineers to make the design and installation process as straightforward as possible. If you can read construction drawings and are familiar with using basic power tools, especially a rotary hammer or a hammer drill, it's likely that you can install the necessary connectors.

These connectors give protection for F0, F1, and F2 tornadoes, which account for 95 percent of tornado activity. (For protection against an F1 tornado, Simpson Strong-Tie products cost $0.25 per square foot during new home construction. F2 protection costs $0.50 per square foot.)

Once winds start clocking in at around 165 mph, speeds equivalent to an F3, things get a little tricky. "By the time you get to that point, you're having problems with windows and roofs resisting those winds," says Randy Shackelford, vice president of the Simpson Strong-Tie Company.

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