If you live where wind storms rage, having a safe room can be life-saving protection. Tornadoes, hurricanes, derechos, and tropical storms can whip wind into a frenzy and effect property damage, injuries and even death.

There are three options when it comes to safe rooms: designate an existing room, such as a basement, construct a shelter anew or purchase a prefab structure. No matter which option you choose, follow Federal Emergency Management Agency (FEMA) guidelines, which will give you “a very high probability of being protected from injury or death.” FEMA’s P-320 guide “Taking Shelter From the Storm” covers everything from building plans and cost estimates to different room types and siting.

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Factors to consider

Size. Safe rooms for single family dwellings or two-family units need at least three square feet of space per person. (Apartment and commercial buildings that house many people need to allow five square feet per person.) Note that comfort can depend on the kind of storm you’re weathering. Tornadoes do not not typically last as long as hurricanes, so there is less need for storage space and comfort options like beds.

Location. Inside or outside? Think about the kind of storm you're most likely to experience and the travel time to the safe room. Tornadoes can hit fast, so a safe room needs to be readily accessible from all parts of your home. Other storms may allow you more time to reach shelter. In that case, the shelter can be located outside, either as a separate structure or adjacent to your home.

Type. Basement? Interior, ground floor room? Exterior shelter? Before you think about building a safe room inside your house, it’s important to note that most reinforced interior walls or even traditional basement walls are not sufficient barriers for safe rooms. Safe rooms need to be planned and built as “structurally separate space,” according to FEMA guidelines. That means they can't be reliant on components designed to provide lower levels of safety. FEMA says any existing building elements that might be structurally important would likely need to be replaced. 

A reliable basement shelter would be best constructed when a home is first built. That's because concrete slabs used for foundations require steel reinforcement to prevent cracking and extreme wind loads.

The type of soil you have is another factor. The soil needs to be able to carry the weight of the safe room.

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Materials. “Extensive testing by wind engineering research facilities has shown that walls, ceilings, and doors commonly used to meet minimum building code requirements for standard building construction cannot withstand extreme wind pressures or the impact of debris carried by these extreme winds,” warns FEMA. That means special building materials must be used to brace the safe room or shelter. Like any other room, doors are a big vulnerability. (Obviously windows are not safe.) Storm safe doors, hardware and assembly for locks and hinges are all needed to anchor the door frame to the surrounding safe room wall.

Cost. According to FEMA, the basic cost to build a safe room is between $8,000 to $9,500 for an 8-foot by 8-foot structure. Prefab shelters (14 feet by 14 feet) cost between $14,000 and $17,000. As a general rule, safe rooms for existing homes are more expensive than those constructed for a new home because of the retrofitting required.

Safe rooms run the gamut from simple, bare spaces to tricked-out shelters replete with surround sound, WiFi, solar power, plumbing, surveillance systems and escape tunnels.

Whichever choice you make, abide by FEMA’s recommendations and building codes to ensure your safe room lives up to its name.

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Thomas M. Kostigen is the founder of The Climate Survivalist.com and a New York Times bestselling author and journalist. He is the National Geographic author of "The Extreme Weather Survival Guide: Understand, Prepare, Survive, Recover" and the NG Kids book, "Extreme Weather: Surviving Tornadoes, Tsunamis, Hailstorms, Thundersnow, Hurricanes and More!" Email kostigen@theclimatesurvivalist.com.