Safe room build question

[930dreamer]

A friend is looking to build a 14x10' room inside a new construction house/garage build. Sounds like cinder block will be used for the walls. Will the slab under this area need a footing? Just in the design phase now.

 

[Old Man Roger]

I'm no engineer, but it would depend on what he wants those walls to stand up too, right? I mean if it's just for security against burglars, I wouldn't think it would need it, but if it's for protection against tornadoes or hurricane, then maybe?

I guess I should have just said''subscribed'' lol

 

[LB-1911]

A friend is looking to build a 14x10' room inside a new construction house/garage build. Sounds like cinder block will be used for the walls. Will the slab under this area need a footing? Just in the design phase now.

Start here

https://www.fema.gov/media-library-...709/FEMA_P-320_2014-ConstructionPlans_508.pdf

In-residence Shelters

 

[930dreamer]

Build won't be in Texas but good information, probably will have a precast roof.

 

[Moosefire]

I'm no engineer, but if the wall is in anyway going to be load bearing, other than just the weight of the wall itself, then I would put in a footer. At this point, not doing it is going to save you what... a few hundred bucks in concrete and labor? Even if it was 1500 bucks it's time and money well spent so that you know you wont have problems with cracking ir sinking in the future

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[cvairwerks]

All I’d say is study what stayed put in the Jarrell, Tx storm. There were sections of town that the storm pulled up concrete streets.

 

[txvwnut]

All I’d say is study what stayed put in the Jarrell, Tx storm. There were sections of town that the storm pulled up concrete streets.

If I remember it right there was nothing left in Jarrell. I had racer buddy who was a hazardous claims adjuster and said that was the easy claim job he’d ever had as nothing was left.

 

[Kaizen]

If I were going through the effort of making a concrete safe room I would fill the blocks in the walls and make sure that there was a footing with rebar tied throughout the entire structure including the roof


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[sberry]

Couldn't hurt to put a dip in it and toss a couple rods along it.
But since this is in design and precast roof might have a real book learned engineer give it a go and see how much to add features and strength so it rip the house right away and still have a semi inhabitable structure, even one end with a wall across and dividing wall, 1/3 more blocks but super stronger with 2 rooms essentially.

 

[930dreamer]

Use won't be for storm protection, will have a vault door.

 

[rjacobs]

2 courses of 8" block with rebar minimum...

8" thick you can get in with a 14-16" demo saw that can be rented/stolen from just about anywhere... So you need the thickness to defeat that. And the rebar will usually destroy a masonry blade pretty easily.

I would have the concrete crew form it, rebar it and pour it vs. using block. Thats me personally. I bet it dont cost much more than doing block and it would be a TON faster and easier. Cut the opening for the vault door later.

 

[brownbagg]

yes, no, you just make the slab thicker in that area under the wall, throw a number five in

if wall gets poured, yes, if left hollow no

 

[PugetDude]

Use won't be for storm protection, will have a vault door.

If you have so many valuables that you are building a dedicated vault room to store them in, you can afford to put proper footings under it.

PS: a sheet of stainless steel makes a great ceiling.

 

[NUTTSGT]

In the prebuild stage, I'd definitely add a footer for the block to sit on. Like Moose said an extra couple hundred bucks in concrete. What's extra $350-500 in a $350K build ?

 

[pbon]

Zombies can get through anything.

 

[strength_and_power]

May want to look into an actual modular vault. A 5 sided vault would use the foundation as the floor and have its own ceiling. The panels weld together and a Class 1 panel is only 3.5” thick and resists 30 minutes of net working time attack. When you start talking about double rows of cinder blocks, you are actually talking about 4 rows, left and right side, front and back which is going to eat up some square footage. Had a jewelry store customer years back who insisted on pouring his vault walls rather than using actual vault panels. His insurance insisted on 14” thick walls to be insurable.
It really depends on the person’s level of paranoia.
Class 1 six sided vault. 24,000#s if I remember right. Roughly 8’x10’



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[Boomer9275]

Just went through this last year in our build. Engineer had us pour a footer under the walls and then formed and poured them 10”thick with basement walls. We put ours under the front porch so we had a concrete ceiling as well. It might have added 3-5k to build cost but like people before mentioned in a 350k build that’s minimal. Smith security safes makes really nice vault doors pretty reasonable as well.


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[matt_i]

In the design phase its super easy to just thicken the slab there. That's the only footing you are going to get if its slab all around it anyway.

 

[orangeblood]

All I’d say is study what stayed put in the Jarrell, Tx storm. There were sections of town that the storm pulled up concrete streets.

1997
Class F5
Max winds 240+ MPH

 

[alfazer]

If he can still get a crane in there, he could drop in some precast concrete box culvert.

 

[Pate]

I had my walls poured when the foundation was poured. Cut out for vault door was also prepped.

 

[dcg9381]

A friend is looking to build a 14x10' room inside a new construction house/garage build. Sounds like cinder block will be used for the walls. Will the slab under this area need a footing? Just in the design phase now.

Technically, that's an engineering question for a slab engineer. Off the cuff, I think it would bear a little more weight density than a standard brick ledge - maybe less per sq/in.

I have a neighbor with a custom home - I've watched the safe room go in. It's got a 24" footer all the way around the perimeter. The installed rebar into the footer and will concrete block all the way up, filling the concrete blocks (I assume connecting additional rebar).

The fault I see in their design is that I'm not sure they've capped it with anything... (but it hasn't been completed yet).

Around here you can get pre-cast shelters (concrete or steel) that are tornado rated and bolt into place.

 

[Teutonics]

I have a family member that builds commercial bank vaults and personal safe rooms/vaults. He travels all over the country to build vaults and has done a LOT of work in Texas. PM me if you want his contact information.