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I have a 1960s 10x12x8 ft concrete room. It was built under our concrete kitchen floor which is at ground level in 1963. The concrete is 12" thick, except for the ceiling which would be about 24" thick. I do not know if it is rebar reinforced. It has a 36 inch doorway opening in the basement and is otherwise 100% concrete. The doorway just has a simple hollow core door.

This was built in the 1960s when everyone was afraid of nukes. In recent years however we've received a lot of local tornadoes that touch down within miles of me. Last night we had one right on top of us (took out a few houses near us) and we all used this as a shelter. Is this a decent shelter or not? What should be done to it in order to make it a safe shelter? Assuming it should have some sort of shelter grade door instead of the interior hollow-core it has now? There is no venting in there either. It appears to be the start of a bomb shelter that was never finished.

  • Although not an area of my expertise, I would be concerned with two issues. The hollow door and if the house collapsed into the cellar would you have a means of exit. – mikes Jun 25 '15 at 23:10
  • That's my concern as well... the collapse... – maplemale Jun 26 '15 at 21:25
  • at ground level in 1963 Has the ground level settled or changed in that time? – psaxton Jun 25 '18 at 19:49
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I agree with @paul: the room should be adequate for protection from a tornado.

However, a bomb shelter was/is designed with different assumptions than what one would design a storm cellar for, primarily that once the bomb shelter is occupied, that there would be no hurry in opening the door for quite awhile. Also that there is little need for outside communication since it is generally assumed that the phone company is gone and probably all radio stations.

A hollow core door is something of a concern due to over-pressurization and under-pressurization between the room and the kitchen during a storm could (and probably will) bust up the door and turn it into nasty projectiles. A nice heavy solid core door is much more likely to perform satisfactorily. It is possibly better to have no door than a hollow core.

Items to consider adding:

  • A cell phone repeater located just outside the shelter should easily be able to receive cell phones from inside where the 12–24 inches of concrete might make cell phones otherwise useless.
  • A pry bar, handsaw (for cutting lumber), hacksaw (for cutting rebar), and sledgehammer would be good insurance inside to be sure you can get out when it is time.
  • Several battery powered lights
  • Plenty of water and food
  • A porta-toilet
  • First aid kit
  • You are carrying your cell phone into the shelter with you, right?

In all likelihood, you would be in the shelter for only a few minutes less than once a year. But having the supplies to be comfortable for several days is great insurance even for non-tornado events when you wouldn't even use the shelter.

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    Many storm prone communities now allow you to register your shelter with a Public Safety Official. In the event the house did collapse they would be aware that you may be trapped in your shelter. – mikes Jun 26 '15 at 21:44
  • Good to know... – maplemale Jun 26 '15 at 22:23
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    That hacksaw should have multiple spare blades rated for cutting metal (i.e. high TPI). Given this is in the basement, I would also have a battery-operated reciprocating saw handy, again, with multiple good blades. Grab it on the way in. – user4302 Jul 3 '15 at 0:40
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As a rough guess, 24 inches of concrete should be able to handle a house falling on it. Certainly better than the basement bathroom. I would change the cheap door for a solid wood one just on general principle though. You want it to open in, otherwise one fallen beam in an otherwise clear basement could lock you in there for a while. Put a small saw in the room.

The lack of ventilation makes sense - the last thing you want after a nearby nuclear blast is an outside air vent.

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    Good point on opening the door inward. Wouldn't have thought of that! – maplemale Jun 26 '15 at 21:30
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Ideally a storm shelter should be located nearby but away from the house, so that there is no risk of the structure collapsing and trapping the occupants. But if you're going to have something in the same building, this sounds like a pretty good situation.

The main risk in a tornado is not actually building collapse but flying debris, and being in the basement makes this basically a non-issue. I wouldn't bother reinforcing the door since you're below ground; there won't be much debris blowing around.

I don't know where you are or how long tornado warnings last, but if it were me I would just put a couple jugs of water and some energy bars in there and not worry about it too much. Honestly the risk of death from a tornado is extremely low. According to NOAA it's about 60 per year. Compare that to 600 accidental gun deaths; 3000 killed in building fires; 13,000 by skin cancer; and 33,000 killed in car accidents.

  • "Ideally a storm shelter should be located nearby but away from the house" So if a tornado is approaching, tossing all kinds of debris about, you want me to go OUTSIDE to the bunker? – paul Jun 27 '15 at 0:06
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    @paul: yes, that's right. NOAA tornado warnings are typically at least 10 minutes in advance. Tornados are somewhat unpredictable but do not just appear out of the blue the way an earthquake might, for example. But as I said in my answer, a tornado is a relatively low-risk event. – Hank Jun 27 '15 at 3:57
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    Maybe it depends on where you are in relation to the Tornado. Last week, the warnings appeared about 30 seconds after seeing a funnel cloud right on top of us. Normally we get tornado sirens going off a good 5 - 10 minutes before like you said along with alerts on our phones. Phone service, power and internet where out before we got any warnings. It touched down about 1/4 - 1/2 mile up the street and took out 3 houses. No doubt, they had no warning at all. – maplemale Jun 29 '15 at 14:50
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I recommend using the basement shelter as your back-up plan, but also installing a below-ground shelter in your yard, assuming you can place it 100-250 feet from your house. If you need to shelter and can safely make it outside, go to that shelter. If you can't go outside, go to the basement.

There are many bad things that can happen in a house which has been struck by a tornado - in addition to your house collapsing in, or debris impeding your way out, if a tornado strikes your house, it could cause a fire, flooding, electrical shock risk, or explosions. Being in a storm shelter even 100 feet away greatly reduces your risk.

  • More good points... I didn't even think about fire. Thank you! – maplemale Jul 1 '15 at 16:31

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