storm shelter

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Old 06-13-08, 05:30 AM
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storm shelter

Are there any plans or tips/instructions on turning your basement into a storm shelter against tornados on line anywhere?
 
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Old 06-13-08, 05:47 AM
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storm shelter

Go to the FEMA site (fema.gov or fema.org?)

Look for information on "safe cells" or something like that. There is a downloadable pdf that you can view or save. I think it is FEMA 320.

Dick
 
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Old 06-13-08, 06:06 AM
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thanks that helped some but i have already read that and it doesn't help the do it yourselfer like me very much.
I guess I want to know should i reinforce the ceiling (floorjoists) in my basement and would the basement be safe enough without having a actual "safe room or cell" built inside the basement.
 
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Old 06-13-08, 08:12 AM
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storm shelter

You can go a far as you wish for safety and what risks you want to take. The FEMA guideline also provide some suggestions of area and supplies. The guys that did much of the testing have great job shooting 12' 2x4s out of an air cannon and seeing how far they go through. The standard is no penetration for obvious life safety reasons.

The FEMA guielines on safe cells are based on the fact that a tornado is not like a hurricane. If it hits you, there will be almost total distruction instead of just 100-130 mph linds.

Much of it is based on protection from projectiles and debris, which is why the only reasonable method of wall construction is reinforced block or reinforced concrete. The roof/ceiling construction is also reinforced concrete because of the projectiles and what may end up on the roof (like your house or a car).

You could easily build the reinforced block walls in a basement and call it storage with a heavy, inswinging door. The ceiling is a different story. It has to be strong enough to protect from projectiles and support unknown loads. This means it has to be strong and not subject to uplift like a wood floor system. A concrete ceiling actually may be easier than trying reinforce an existing wood floor and then try to hold it down to the foundation. - Conventional anchor bolts, even if closely spaced are still pretty feeble, because they are just attched to wood.

Obviously, a corner location in a basement is cheaper and easier. Reinforced block walls are reasonable, but the construction of the concrete ceiling would be a challenge rrequiring drilling a few 4"-6" holes for access.

About two weeks ago, we had a EF3 tornado hit 5 miles north of us. Virtually every home was destroyed(leveled) and 2 kids were in one basement. - One drowned in the pond he was blown into and girl is still in critical condition.

The safe cells are now becoming more common and serve dual purposes like walk-closets and even bathrooms in new construction in the midwest.
 
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Old 06-13-08, 03:14 PM
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Originally Posted by wwc View Post
I guess I want to know should i reinforce the ceiling (floorjoists) in my basement and would the basement be safe enough without having a actual "safe room or cell" built inside the basement.
That will provide no help, trust me! Look at where I live, Moore, OK. We had the biggest tornado ever recorded roll through and destroyed our homes.

Floor joists are just tooth picks to a twister....
 
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Old 06-13-08, 05:18 PM
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Wow I had no idea, thanks.
I guess we have just been very lucky and dumb in thinking the basement was safe. better than nothing but not much i guess.
 
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Old 06-13-08, 09:41 PM
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do yourself a favor and install a saferoom in the basement or a storm cellar out side. We are about to start new construction and have already planned for a safe room in our basement. after the f5 on may 3rd in 1999 you wouldn't belive the damage that it caused, I saw foundations that had nothing left on them even the pipes were broken/worn off at concrete level. it even pulled up the grass where it crossed I-35 in moore. on E I-240 where a heavy equipment sale yard was located it looked like a giant egg beater had been over the ground and all of the earthmovers and dozers were just scrapmetal. if a major tornado hits dead center you must be underground or behind at least 10-12 in of reinforced concrete.

life begins when the kids leave home and the dog dies
 
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Old 06-13-08, 10:10 PM
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Years ago I had opportunities to visit folks in Nebraska. Rural folks had storm cellars built into the ground. I visited an old home place built in the 1800's. The cellar was dug into the ground and had a wooden door that could have easily blown off, but was still intact. Other properties had cellars dug into sides of hills and embankments. New construction had specially constructed concrete rooms built under stairs and had extra thick concrete floor, walls, and ceiling. As indicated, you need protection on all four sides as well as above, and it needs to be secure. If you have existing construction, then building a storm cellar outdoors to specifications for safety tends to be the general recommendation.
 
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Old 06-13-08, 10:59 PM
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I don't think a outside shelter will happen, I don't have much room and there is always the expense issue of digging it all out.
the basement is fast to get to but thats a good point from you have been directly hit, i don't think i would be totally safe in my basement without reinforcements.
And with that expense it doesn't look like i can afford to install a safe room very soon.
I do appreciate all the replys, all good advice.
I wish there was a cheaper way to be safe instead of depending on luck.
 
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Old 06-13-08, 11:42 PM
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Building a safe shelter or cellar can be expensive. In the meantime check out the links provided here: http://www.extension.iastate.edu/acr.../aljune99.html
 
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Old 06-14-08, 05:20 AM
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Sort of late jumping in, but, Dick, wouldn't a poured monolith with rebar be a better choice than block, even if you were to go with 12" block? We just did a monolith pour for a retaining wall behind a new high school athletic building, and it looks like it would take and RPG attack! I know it may not be practical in an already finished basement, but in new construction, that extral two walls in a corner look formidable.
 
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Old 06-14-08, 07:37 AM
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storm shelter

The 8" thick rinforced block and the 8" thick reinforced walls performed the same to meet the projectile pentration. The 8" rebar spacing is suggested and spacing will even change the performance for a pourd wall. The tests were done at Texas Tech.

The FEMA suggestions were made to maintain life safety and do not require any special strengths because the rooms are small and the corners provide a lot of rigity.

If necessary you can go to 5000 psi concrete or get block strengths higher than that.

Dick
 
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