Tornadoes and hurricanes are not unexpected events—they happen every year in very predictable places.
Over the years, builders have taken steps to boost wind resistance in the houses they build, but unfortunately, brick veneer, foundation bolts, and hurricane straps won't usually stand up to an F5 tornado.
To ride out tornadoes, people often head to the basement or an interior room, such as a closet or bathroom. Sometimes bathtubs and couch cushions provide the necessary shelter to get through the storm.
To step up the level of protection, and increase comfort, many people have pre-made safe rooms installed—big steel boxes bolted to the floor. They are like people-safes that start around $3,000.
You can also build your own safe room.
A little before tornadoes ripped through Moore, Okla., in 1999, FEMA published a 58-page book on how to build a safe room. Taking Shelter From the Storm, Building a Safe Room for Your Home or Small Business, FEMA P-320 is now in its third edition, last updated in 2008. It is a free download.
FEMA defines a safe room as:
A hardened structure specifically designed to meet the Federal Emergency Management Agency (FEMA) criteria and provide "near-absolute protection" in extreme weather events, including tornadoes and hurricanes. Near-absolute protection means that, based on our current knowledge of tornadoes and hurricanes, the occupants of a safe room built in accordance with FEMA guidance will have a very high probability of being protected from injury or death.
Above-ground safe rooms can be built in a basement, crawlspace, or on a slab. They can be constructed with standard building materials—though beefed up considerably. Basement lean-to rooms are built with 2x4 framing; each stud is doubled-up and the wall is sheathed with two layers of 3/4-inch plywood over a layer of 14-gauge steel sheathing.
The main point of weakness is the door; the hinges and latch are the critical links. To secure the latch, FEMA says to use "3-locking pins, dead bolts, or slide bolts with min. 1-inch throw surface—mounted to astragal with #8 x 3-inch wood deck screws." (The 1x3 astragal is fastened to the double 2x4 framing with 3-inch deck screws).
On the hinge side, use 4-inch heavy duty 5-knuckle hinges with U.S.-manufactured full-head screws. Offset the middle hinge from the deadbolt.
The FEMA detail package has five designs: concrete, concrete masonry, wood-frame, lean-to, and in-ground. Each design should perform equally well in resisting extreme winds.
On its website, FEMA says there are grants and other funding opportunities available for people who want to build a safe room in their home.
Community development grants, FHA financing, and FEMA grants can help you pay for the construction in 12 states.