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aka Mental Avenger
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Discussion Starter #1
Earthquake, Tornado, Safe Room
In the DIY forum I started a thread on Building A Safe Room in Your House. That got me to thinking about the level of damage and loss of life in the recent disasters.

Most homes and building seem to be standard frame construction that can be blown to bits by any tornado. I understand that, in addition to the force of the wind, most of the damage is caused by flying debris. In an area that is leveled by a tornado, there may be two or three buildings that remain standing.

I can understand why homes in Tornado Alley are not built to be tornado proof as that would cost a fortune. But, it seems to me that homes in those areas should have one room that is built to withstand virtually any tornado. Although it is easier to construct such a room during the initial home construction, a tornado safe room could be built into any existing home. The best place to build it would be in a basement, but if the home doesn’t have a basement, any ground floor room would do.

Standard home construction is a 2x4 stud frame on 16” centers, covered in sheet rock on interior walls and OSB on exterior walls. To reinforce an existing room, the interior sheetrock can be removed and two additional 2x4 studs spaced between the existing studs. Doorways can be reinforced with additional 2x4’s over the top plate and additional 2x4’s screwed to the existing stud door frame.

Over that add ¾ inch plywood, attached to the studs with construction adhesive and 3 inch #10 deck screws. Over that add another overlapping layer of ¾ inch plywood, bonded to the first with construction adhesive and held on with 3 ½ “ #10 deck screws every 6 inches.

The hard part is the ceiling. The strongest way is to go into the attic and add a layer of ¾” plywood over the ceiling joists. Then add 2x6 ceiling joists every 6 inches over that and an additional ¾” plywood over that. Alternately, from inside the room, the sheetrock can be removed, additional ceiling joists added between the existing joists, with ¾” plywood over that just like the walls.

Replace doors with steel doors, and add heavy shutters over the windows.

A room like this should be able to survive any tornado or earthquake.
 

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That's really not a bad idea. And, (I know most of you are against Gov mandates but) if there was legislation mandating a "safe room" in homes in tornado prone areas, there would be a short term boom in construction jobs as an added bonus.

I've heard too many stories of people in bath tubs holding mattresses over their children to keep them safe. Its sad, and devastating that people lose their lives needlessly.
 

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This seems like a practical and cost saving idea and I am considering doing this to our walk-in closet off the master bedroom/bath. Additionally, this room already has no windows and is the furthest room from the predominant direction that these storms travel from. I can do all of the work myself but my one question would be how to strengthen the sill plate connection with the stud walls. Do you think that adding the overlapping 3/4" layers of plywood would make that connection to the sill plate stronger? I have no doubt that protection from flying debris would be greatly enhanced, just worried about integrity of the room for a hit by an EF3-EF5 tornado. What are your thoughts?
 

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aka Mental Avenger
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Discussion Starter #4
This seems like a practical and cost saving idea and I am considering doing this to our walk-in closet off the master bedroom/bath. Additionally, this room already has no windows and is the furthest room from the predominant direction that these storms travel from. I can do all of the work myself but my one question would be how to strengthen the sill plate connection with the stud walls. Do you think that adding the overlapping 3/4" layers of plywood would make that connection to the sill plate stronger? I have no doubt that protection from flying debris would be greatly enhanced, just worried about integrity of the room for a hit by an EF3-EF5 tornado. What are your thoughts?
What is your sill plate currently sitting on and how well is it anchored? If it is anchored like this, you might consider putting in more anchors using 5/8” anchor bolts, washers, and nuts.


Sections of 2x4 between every other wall stud allows you to easily end nail them to the studs, then screw them down to the sill plate. You will have to drill holes in those sections for the anchor bolts. Overlapping the plywood might be difficult if the floor is built up even with the top of the sill plate. If not, overlapping the plywood would be extremely strong. Remember, the entire structure is dependent upon how well the sill plate is anchored to the foundation and how secure the foundation is.
 

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thats pretty much like what I was thinking, the foundation is concrete slab, overengineered with about 50% more concrete than necessary and post tension cables running throughout. Im not sure exactly how the sill plate is attached but was thinking of using hammer drill and sinking additional anchors like the kind they use to retrofit the steel box shelters inside the home. By adding additional anchor points and beefing up between every other stud bay,I think along with all of the other improvements, this would be a room that could withstand even large tornadoes. Anybody out there with experience please chime in.
 

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That's really not a bad idea. And, (I know most of you are against Gov mandates but) if there was legislation mandating a "safe room" in homes in tornado prone areas, there would be a short term boom in construction jobs as an added bonus.

I've heard too many stories of people in bath tubs holding mattresses over their children to keep them safe. Its sad, and devastating that people lose their lives needlessly.
I would be surprised if communities in Tornado/Hurricane prone areas didn't pitch in and build a hardened shelter (above or below ground) that could be opened in emergencies.

A "safe room" in a house isn't much use if the whole house gets ripped off its foundation and tossed across the street.

IMO it's too costly for every person to have a hardened home, better just to have a bombproof emergency shelter in each community that is known to everyone. The odds even in the tornado belt of getting pulverized by a twister is still extremely low, so I'd rather pitch in $500 to a community shelter than $50,000 hardening my own home.

Over here, decades ago the government mandated all colleges/universities/schools to have underground bomb shelters installed. Not far from where I sit is such a building, I've been in it before and it would serve the purpose in a firestorm/tornado/hurricane/war/etc. Very unassuming on the surface, just a thick steel door, chimney, and that's it.

Not too fond of any mandate but I can think of many worse ways to "waste" taxpayer money than on underground hardened shelters at educational facilities.

In the end, mother nature is mother nature and there ain't much humans can do when she's in a bad mood!
 

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>A room like this should be able to survive any tornado or earthquake.


Hardly.

You need poured concrete walls reinforced with rebar or block walls with the cavities filled with concrete and rebar from top to bottom.

I watched a show where they had a puematic cannon that would shot 2x4's around 200 mph to simulated a tornado. 2x4 would punch right thru a regular block wall. When they filled the cavities with concrete and rebar they could stop the 2x4.

Extra plywood would be better than nothing but I would seek better shelter than that if I had the time.

McLOVIN
 

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aka Mental Avenger
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Discussion Starter #10
I would be surprised if communities in Tornado/Hurricane prone areas didn't pitch in and build a hardened shelter (above or below ground) that could be opened in emergencies.
AFAIK, many places do just that.

A "safe room" in a house isn't much use if the whole house gets ripped off its foundation and tossed across the street.
The FEMA documents include designs that address that problem. Building a safe room into a basement is the best solution. Notice that in many tornado disaster photos, the bathroom is the only part of the house left standing. Perhaps that is because of the extra reinforcement of heavy fixtures, extra layers of greenboard often used, and the pipes in the walls. Also perhaps because the bathroom is usually smaller and therefore has more supporting walls per volume.

IMO it's too costly for every person to have a hardened home, better just to have a bombproof emergency shelter in each community that is known to everyone. The odds even in the tornado belt of getting pulverized by a twister is still extremely low, so I'd rather pitch in $500 to a community shelter than $50,000 hardening my own home.
IIRC, especially lately, warnings have not been far enough advanced to allow people to go very far. In the event of a short warning time, traffic could put many people in harm’s way if the shelter was not close by. Perhaps one shelter for every ten square blocks would work.

Over here, decades ago the government mandated all colleges/universities/schools to have underground bomb shelters installed. Not far from where I sit is such a building, I've been in it before and it would serve the purpose in a firestorm/tornado/hurricane/war/etc. Very unassuming on the surface, just a thick steel door, chimney, and that's it.
When I was young, I took a Civil Defense course in Shelter Management from the University of Wyoming. We practiced in a CD shelter in the basement of a large stone building.

Not too fond of any mandate but I can think of many worse ways to "waste" taxpayer money than on underground hardened shelters at educational facilities.
You got that right.

In the end, mother nature is mother nature and there ain't much humans can do when she's in a bad mood!
Especially when mankind creates that bad mood by pollution?
 

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aka Mental Avenger
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Discussion Starter #11
>A room like this should be able to survive any tornado or earthquake.

Hardly.

You need poured concrete walls reinforced with rebar or block walls with the cavities filled with concrete and rebar from top to bottom.
Few things will be absolutely safe. It is a matter of diminishing returns. A room with studs on 5 inch centers and 1 ½ inches of bonded plywood should be able to withstand 95% of the tornado damage, compared to perhaps 5% for an average home construction.

I watched a show where they had a puematic cannon that would shot 2x4's around 200 mph to simulated a tornado. 2x4 would punch right thru a regular block wall. When they filled the cavities with concrete and rebar they could stop the 2x4.
I can punch through a non reinforced block wall with a single blow from a sledge hammer. I’d have to beat on a 1 ½ inch bonded plywood wall with that sledge for quite a while before being able to break through.
 

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I've never lived in tornado alley, although we did live in two places on the east that did have tornados, though infrequently. We always bought homes with basements to use as shelters, and if none had been avaialable, we would have put in at least a rudimentary storm shelter in ground. I am curious as to why people don't have storm cellars or basements when they live in areas prone to storms like that? Not trying to say anything bad, just honestly wondering.
 

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Patient Zero of WWZ
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But, it seems to me that homes in those areas should have one room that is built to withstand virtually any tornado. Although it is easier to construct such a room during the initial home construction, a tornado safe room could be built into any existing home.
I don't think even a concrete room above ground would be safe if it took a direct hit from an F5. The only safe place is below ground.

But a good strong room or closet would greatly improve your chances of surviving a near miss or a smaller tornado.

I used to see a guy at a flea market near Dallas selling a sort of portable shelter.

It was made to look like a piece of furniture A dressing bench that you would set at the end of your bed and sit on while dressing.

Inside it was framed with 4x4 lumber and the walls of it were 3/4 inch plywood. A house could fall on this thing and it would not have collapsed.

When the alarms go off you just crawled inside the thing. Better than nothing. Way better than a closet orfiberglass bath tub.

A handy person could build one themselves.
 

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Patient Zero of WWZ
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I've never lived in tornado alley, although we did live in two places on the east that did have tornados, though infrequently. We always bought homes with basements to use as shelters, and if none had been avaialable, we would have put in at least a rudimentary storm shelter in ground. I am curious as to why people don't have storm cellars or basements when they live in areas prone to storms like that? Not trying to say anything bad, just honestly wondering.
Most of the recent tornadoes, and all the recent big ones were OUTSIDE of tornado alley.

This page has a map of what people traditionally call Tornado Alley
http://www.nationalatlas.gov/articles/climate/a_tornadoes.html

Tornadoes can happen anywhere. Even New York City
http://www.nbcnewyork.com/news/local/Tornado-Warning-Issued-for-Eastern-New-York-City-103086814.html
 

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A "safe room" in a house isn't much use if the whole house gets ripped off its foundation and tossed across the street.
On the contrary. There was a tornado here a few years ago where a house was wiped off the foundation and the 5 people survived in the concrete storm room.

IMO it's too costly for every person to have a hardened home, better just to have a bombproof emergency shelter in each community that is known to everyone. The odds even in the tornado belt of getting pulverized by a twister is still extremely low, so I'd rather pitch in $500 to a community shelter than $50,000 hardening my own home.
When a tornado hits with little warning at 3am I'd rather just have to gather the kids up and go downstairs/into the storm room than to run all over trying to get to the community shelter. That would be a great idea for hurricanes/cyclones, etc, but not for storms like tornados, which give little warning. And $50K is a bit over the top. You can add a room with 12" thick concrete walls and roof during construction for a fraction of that.
 

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if it were me, i'd just buy and install one of these....some ballistic protection too...

http://www.newdaytornadoshelters.com/Work.php
I dont like this one at all. A well thought-out tornado shelter has a door that opens INWARD. If this unit does survive a tornado, your house material could just pile on top, locking you inside until someone digs you out.

As far as reinforcing your walls with more studs, personally I put no faith in wood vs a tornado. I have seen too many trees ripped up, knocked down, thrown about, and even telelphone poles snapped. Telephone poles are NOT fragile things. Most folks dont have $20k for a real tornado shelter, so whatever you can afford could help "some". But please don't consider "job done" by reinforcing wood walls with more wood. Only steel reinforced concrete measured in feet can guarantee against a tornado.
 

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If you think only concrete will stop an F5 you should check out the steel rooms that are sold to be bolted to your existing slab. Somebody had one in their home in one of the recent F5's and they stumbled out of it and saw that it was the only thing standing in their neighborhood. These are tested at Texas Tech University to withstand F5 force. I wish they would take overlapping, bonded and screwed sheets of 3/4 plywood and fire the cannon at it to see what would happen. Remember how plywood is constructed. Anyone stating there is no way that this would offer substantially more protection doesnt have much construction experience...
 
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