Safety in garage floor / in ground vs above ground tornado shelters ?

[blckthree]

Blkthree, you do realize that you can still put car in the garage. The shelter looks like a pit at a oil change shop with a sliding door on it. You park the car on top of it.

Yes, I realize that, but getting dogs down those steps would be quite a trip.

Mike

 

[JonDough]

We're going through the same decision problem. I've about got it narrowed down between a big in ground precast or the 9.5 x 9.5 OZ unit. In ground pros are, our ground is pretty stable here so i don't think there'd be a cracking problem....there's no water or gas lines close to where the shelter would be and i just have it in my head that we'd be safer underground also the temperature in the summer would be better with the in ground unit (had one in the past).

BUT........that big OZ unit is looking pretty good...and at 70,000 pounds of concrete and steel...Dayam.... seems like it'd stay put. Plus there's NO chance of water leaks, etc..etc. I guess i'll look into the Oz units a little harder. Even the medium unit is looking promising. I guess my whole problem is getting over the real or imagined thought that we'd be safer under the surface.

 

[Glock]

^the extremely high water table on the property is why we're doing the 9.5 OZ, every underground the parents had here seemed to always fill with water. Plus, I might retrofit it with a safe door lol. Gun/life vault!

 

[pen25]

my water table is at 25 foot and the last time i dug a hole with any kind of depth it filed with water. so if i put an in ground shelter in ill have to also put in a french drain in as well. for those that have the garage in ground setup how was it put in? how was the drainage determined? was there a french drain put in? the problem with in ground shelters in this state is the soil and its drainage and why most basements flood unless sealed and proper drains put in. also on the in ground garage setups i do not see raised vents. is the only ventilation through the door?

 

[yukonjack]

Good point, but just saying there haven't been failures only paints part of the picture. What I'd like to see is just how many above ground shelters have been subjected to EF-4 or 5 direct hits and what the result was.

In other words, all the anecdotal stuff is worthless. Where's the empirical data? Someone's got to have it collected, somewhere.
If I ever build new again, I'd like an above ground but right now the money doesn't even out in terms of what kind of protection $3K gets me for an underground shelter vs. $3K in an above ground.

Sounds like the data is out there. You'll just need to do your own searching for it.

http://www.tulsaworld.com/article.a...look_NWS_official/20130606_777_0_ANatio823340


Professor Larry Tanner from the Texas Tech Department of Construction Engineering and Engineering Technology, said he had inspected 61 of the 199 storm shelters known to be in the path of the May 20 Moore tornado that killed 24.

The idea that it is impossible to survive even the most violent of tornados in a properly built above-ground shelter is a myth, he said.

Tanner showed pictures of homes that were destroyed except for small portions, which were being held up by their above-ground shelters.

 

[Danny Tanner]

How can you tell what your water table level is?

 

[Perplexed]

How can you tell what your water table level is?

There are publications that list the general depths of water in broad areas of Oklahoma, but the best way to determine this in your yard is to dig a post-shaped hole as deep as you need it.

 

[Danny Tanner]

There are publications that list the general depths of water in broad areas of Oklahoma, but the best way to determine this in your yard is to dig a post-shaped hole as deep as you need it.

And then determine my water level based off what? How deep I dug until the hole started filling with water? How quickly it takes the water to fill?

I guess it doesn't matter where I live right now considering we have no space in our house or garage for a safe room and I'm not sure if our HOA allows in-ground units outside of our garage, but I'd still like to know, especially since we only plan on sticking around this house for another few years.

 

[Oklahomabassin]

How can you tell what your water table level is?

Water table changes with long term weather conditions. Last year I was seeing utility crews digging holes for power line poles 6-8 feet deep and never hitting moist dirt. Some areas right now you can hit water at 6-8 feet.

 

[Perplexed]

And then determine my water level based off what? How deep I dug until the hole started filling with water? How quickly it takes the water to fill?

I guess it doesn't matter where I live right now considering we have no space in our house or garage for a safe room and I'm not sure if our HOA allows in-ground units outside of our garage, but I'd still like to know, especially since we only plan on sticking around this house for another few years.

Unless you live out on the High Plains, you can pretty much count on water around the lower part of an in-ground shelter, given enough time. Especially after heavy rains, as OB alluded to in his post.