Tornado Shelter – Part 3

Work on our basement closet/tornado shelter continues. We had some delays yesterday. We needed to borrow some tools and that took some scrounging around town. This meant we had folks come to see what we were up to. Naturally, we needed to break out a beer or two to keep the conversation moving. Then we had to wait for the beer to wear off before we went back to work. Saws and beer don’t mix. But, finally, we did get back to work. SAM_6095

These metal plates with nails add enormous strength against uplift. One way tornados kill is that the tremendous uplift rips off the roof. Once the roof is gone, the rest of the structure collapses onto anyone down below and then if that doesn’t kill you, the tornado blenderizes all that wall material and stuff inside and then shreds everything down to deadly missiles. (I read a tragic story of a two year old who died because a doorknob got inserted into the back of his head by this force. So heartrending!) These strengthening plates are added at all the points where the roof meets the side frame. These plates are also cheap and easy to install. I took on the assignment of hammering in 125 nails into six plates for the back wall which is against the concrete block basement wall. The total cost of plates and nails was under $15 from our local Co-op. It’s little touches like this that greatly increase the strength of the structure with minimal additional cost. You do have to plan these things into it though. You can’t just wing it.

It’s been fascinating watching an engineer plan and then see the plans come together. Our friend Bryan read the plans provided by FEMA and studied some of the diagrams and stats on force and uplift of F0-F5. His eyebrows went up and his eyes went wide a few times as he read. Twice he actually whistled in awe. Yes, tornados are vicious beasties. No doubt about that. To me, the neat FEMA diagrams looked like strange goblety gook lines in black and white but he understood them. He speaks that language.

“Okay, I can see why they do that.”

“Oh yeah, that makes sense.”

“Well, we can get the same amount of protection for a lot less money if we do this instead.”

And all of this knowledge and experience got built into the design. So I recommend that if you want to build one of these reinforced sheltering areas, it would be a really good idea to involve an experienced engineer. First, to make sure the thing holds up against a monster storm, second to save money, and finally, because each place one of these shelters needs to be built in requires special modifications to fit the location. I could have built a closet myself but I could never have come up with this design.

SAM_6096

We are doing the framing now. The studs on the outer wall are spaced every 12 inches instead of the standard 16 inches to increase the strength of the walls by 50%. Since the studs cost under $4 you get a great increase in strength for very little additional cost. The other cheap strength improvement is that all the screws are getting glued in with special construction glue applied before insertion. So you get not just the power of the screw itself, but also the adhesive and that adhesive is really cheap too. Such things do add time.

And the door will open inwards and be partly under the stairs. Our stairs are very well built with dove tailing where the stair is inserted into the stringer so they will take a lot of force. This makes it less likely we’ll be trapped if the building collapsed. We would be able to open the door with greater safety and have a chance of getting out once it’s all over and the storm has moved on.

I sure hope we never have to use this closet/tornado shelter. But if we do, we’re going to have it. I have always been of the opinion that if you prepare for events, they don’t happen. So my little superstition means putting our shelter in, will actually prevent a tornado from coming.

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