Being a home builder in Tornado Alley, I’m often asked how to tornado proof a home. Truth is, if a tornado comes right down on top of your house, there is nothing to be done. It is always a good idea to have a storm shelter or cellar in the event of a tornado bearing down on you. In fact, the only tornado proof shelter is a well built cellar. With that being said, there are two things that I know of that are relatively inexpensive and easy to do that will make your home dramatically stronger in high winds.
Let’s take a look at how your house is built, if you do not live on the coast. First you have your slab, or foundation. Nothing that nature can throw at you in the form of wind can affect your slab. Next step in building is your framing. This is where my two suggestions come in. Now, most framing is secured together with sinker nails which are a 4” long, or a ring shank of similar length. In itself, this is a good way of securing wood together, but in the two places where your house is most vulnerable, sinker nails just don’t cut it.
The bottom of all your framing or “baseplate” is a horizontal 2×4 that lays on your slab. Your baseplate follows the perimeter of your slab and the rest of your framing is secured to it. This is a very important part of building. To secure the baseplate to your slab, you get a tool called a Ramset (see photo). It is pretty much a modified .22 rifle that shoots nails instead of bullets through your baseplate into your slab. Usually, more nail is left sticking out of the top of the baseplate than goes into the slab. The concussion of the shooting effect usually ends up chipping away a substantial amount of concrete, further weakening the bond between nail and concrete. So really, the main thing holding your house to its slab is the weight of the house itself. The fix for this is cheap, simple, and very effective.
The L-Shaped Bolt Secret
Run down to the local hardware store and grab some L-shaped bolts. They need to be long enough to fit 3 or 4 inches into your slab. You will also need a wide washer and nut for every bolt.
When the slab is freshly poured push he L part of the bolt into the concrete and pat the displaced concrete firmly back down on top of the bolt. The more you put in the stronger your baseplate will be. My suggestion would be every hree or four feet. When the slab has dried and is ready for the baseplate, lay your baseplate 2×4 on top of the bolt and hit it with a hammer on top of the bolts, making an indention in the wood. Drill a hole through the indentions wide enough for the bolts to pass through. Lay your baseplate over the bolts and use the washer and nut to secure it into place. Tighten down until the washer begins to make an impression in the 2×4. You now have a very strong base for the rest of your framing to be nailed to.
The next suggestion is still in the framing family. Just like the slab being secured to the baseplate is weak because it’s a transition area, so is the way your roof frame is secured to your walls. This transition is right where your rafters sit on your top plate. If you look at the outside of your house, it is where the soffit meets your bricks. Behind there is your ceiling joist and top plate. In most cases this joint consists of an on end 2×6 being secured to a flat 2×4. The way that these are usually secured together is with a sinker nail, and since it is a weak point the framer usually shoots in an extra 3 to 99 nails to “secure” the joint. Using the “more is better” approach here though can be detrimental because the nails usually end up splintering the wood. And of course the more that are shot, the more the wood splinters.
Instead, make another trip to the hardware store and pick yourself up some brackets to secure the two pieces of wood together, and pick up some 4” torx bit deck screws to do your fastening. These screws will prevent splintering and they hold huge amounts of pressure. It doesn’t matter what shape of bracket your use as long as it is an eighth of an inch thick and fits snugly to both pieces of wood. Alternate the side of the rafter that you put your bracket on as you make your way down the house. Again, this will not “tornado proof” your home, but it will dramatically increase its resistance to high winds.
Remember, a house is only as strong as its weakest point. So take your time and do the right things to make your house a safe home. If you are not comfortable doing these things yourself, feel free to call me. In fact, I’d love to build the whole thing for you from start to finish! And if the thought of tornadoes still bothers you, which it should, we can always talk about putting in a cellar, too.