Gun Safe Math

[Lawdog Dago Dom]

How big is too big for a gun safe on a first floor? No basement, just a crawl space. Home built in 1989. Joists appear to be 16" on center.

 

One big safe or two smaller ones?

 

Not even close to being an engineer, so all feedback is welcomed.

 

Thanks,

LDD

[DeaconKC]

Okay, first off plan to keep the safe as close as possible to heavy supports. You may need to go under the house to locate them. Usually against an outside wall will have good support. Plan on using bolts into wall studs to keep them flush against the wall if narrow ones to avoid tipping.

[JohnWesleyHardin]

I think you will be fine with one unless it falls through the floor.  In that case one was to heavy.

[Badlands Bob #61228]

If it was going to be a big gun safe (1,000 lbs or more) I would seriously consider putting a concrete block pier in the crawl space supporting the floor joists at the safe location.  It would be relatively cheap to do and would give you peace of mind.

[Ozark Shark]

I've had a Liberty Fatboy Jr. installed in a closet in my fourth floor condo for five years.  It's an all wood frame five story building with 2x6 studs and 2x12 floor joists on 16 inch centers.  The safe weighs 750 pounds empty and I would estimate everything stored in the safe adds another 250 pounds.  That amounts to @150 pounds/sq. ft.  Being installed backed against one structural wall and with another very near a side, I've had zero issues.

[Pee Wee #15785]

Put it on the outside wall so it is close to floor plate and sets on 2 or 3 floor joists.  On a inside wall I would sureup the floor under it and get the biggest one you can buy.  Remember guns increase just like rabbets so any size safe is going to be to small in no time.

[Lawdog Dago Dom]

1 hour ago, Ozark Shark said:

I've had a Liberty Fatboy Jr. installed in a closet in my fourth floor condo for five years.  It's an all wood frame five story building with 2x6 studs and 2x12 floor joists on 16 inch centers.  The safe weighs 750 pounds empty and I would estimate everything stored in the safe adds another 250 pounds.  That amounts to @150 pounds/sq. ft.  Being installed backed against one structural wall and with another very near a side, I've had zero issues.

 

Got that one now in a basement, so weight is no issue. But may need another (or two) on a standard joist/plywood floor. So weight would be an issue.

Thanks.

[Michigan Slim]

2 hours ago, Badlands Bob #61228 said:

If it was going to be a big gun safe (1,000 lbs or more) I would seriously consider putting a concrete block pier in the crawl space supporting the floor joists at the safe location.  It would be relatively cheap to do and would give you peace of mind.

I had to do this when the safe door started swinging open with no help. Had to move my ammo safe to an outside wall also to be closer to the foundation. A couple blocks and a jack will run you less than $30.00. Be sure to jack it up some later to account for some sinking if your crawl space has gravel in it like mine.

[Michigan Slim]

And.... Expect to hear popping and some small cracking as you wheel it over the floor to get it where you want it. Don't fret. 

[John Kloehr]

If the building is at all built to reasonable standards, a 1/2 ton (1,000 pounds) safe should not be a problem.

 

Two safes... Now you need to look at which direction the joists run; two safes on the same joists would be an overload on those joists, two safes on different joists might not be an overload.

 

Somewhere around 30 or 40 pounds per square foot becomes an issue, and that square footage is measured on those same joists. Across the span of those joists.

 

Greatly simplified, building codes have more detail.

 

Consider a safe that spans two joists on 16" centers, and the span of those joists is 10' between supports... That is really "about" 3 feet wide because of sub floors spreading the load. 3 X 10 X 40 = 1200 pounds.

 

Across 3 joists (a bigger safe), really about 4-1/2 feet wide, assuming same 10' span. 4.5 X 10 X 40 = 1,800 pounds.

 

I am not a structural engineer nor a civil engineer, just spitballing. Don't see a problem unless you put two heavy safes on the same joists. that could easily be over 2,000 pounds on two joists. Over 3500 on 3 joists with two large safes.

 

If this is confusing, I think I could make a drawing showing why joist direction is a consideration.

[Chancy Shot, SASS #67163]

I would get 2.  A little one for yourself and a big one for Short Cake.  Let her pick the colors!

 

Chancy

[Smoken D]

Generally 1# short of collapse should work.

[Lawdog Dago Dom]

1 hour ago, John Kloehr said:

If the building is at all built to reasonable standards, a 1/2 ton (1,000 pounds) safe should not be a problem.

 

Two safes... Now you need to look at which direction the joists run; two safes on the same joists would be an overload on those joists, two safes on different joists might not be an overload.

 

Somewhere around 30 or 40 pounds per square foot becomes an issue, and that square footage is measured on those same joists. Across the span of those joists.

 

Greatly simplified, building codes have more detail.

 

Consider a safe that spans two joists on 16" centers, and the span of those joists is 10' between supports... That is really "about" 3 feet wide because of sub floors spreading the load. 3 X 10 X 40 = 1200 pounds.

 

Across 3 joists (a bigger safe), really about 4-1/2 feet wide, assuming same 10' span. 4.5 X 10 X 40 = 1,800 pounds.

 

I am not a structural engineer nor a civil engineer, just spitballing. Don't see a problem unless you put two heavy safes on the same joists. that could easily be over 2,000 pounds on two joists. Over 3500 on 3 joists with two large safes.

 

If this is confusing, I think I could make a drawing showing why joist direction is a consideration.

 

I see what you mean. Similar to the Federal Bridge Act of 1974, regarding size, weight and load on trucks. The heavier the load, the more axles to spread it out over the pavement.

Thanks

[Lawdog Dago Dom]

40 minutes ago, Chancy Shot, SASS #67163 said:

I would get 2.  A little one for yourself and a big one for Short Cake.  Let her pick the colors!

 

Chancy

 

I just read her that and she is blowing you kisses

[Lawdog Dago Dom]

1 hour ago, Michigan Slim said:

And.... Expect to hear popping and some small cracking as you wheel it over the floor to get it where you want it. Don't fret. 

Any popping or cracking is probably from my knees.

[Sedalia Dave]

Will My Raised Floor Support a Safe?

[Runamuck, SASS #49216L]

4 hours ago, Michigan Slim said:

And.... Expect to hear popping and some small cracking as you wheel it over the floor to get it where you want it. Don't fret. 

Be sure to miss any floor heater vents, they will make a far worse sound than popping and cracking.....
 

[Still hand Bill]

Consider a safe from zanotti armory.  They come in parts and then assemble in place.   Makes moving a lot easier.  

[watab kid]

"...Okay, first off plan to keep the safe as close as possible to heavy supports. You may need to go under the house to locate them. ........Put it on the outside wall so it is close to floor plate and sets on 2 or 3 floor joists............. I would seriously consider putting a concrete block pier in the crawl space supporting the floor joists at the safe location.  It would be relatively cheap to do and would give you peace of mind........"

all of this is good advice , its my approach to helping a friend here with a nice crawl space condition , his home is well built and has a solid foundation of CMU with a concrete floor in the crawl space , i know the safe & contents will not be the only load , something will get piled on top and around it close , ammo most likely , that adds up quickly , 

 

the residential UBC building code dictates the design loading for floors in structures , you can feel quite confident it will hold that load on that square footage as its slightly overdesigned by regulation , but i would caution exceeding it as the design is intended to keep you safe ,  

 

a good thing about crawl spaces is it gives you access to reinforce the areas you want to , bad thing is all crawl spaces are not the same - here we have concrete floors in them in most developed areas {NO i dont really know why they dont put in a basement unless the water table is inches down] but there are rural areas where they are dirt - not compacted soil , stability is questionable ,

you can use an oversized footprint 3/4 inch plywod over the floor to disperse the load over more joists as well , put flooring or some carpet on it , one needs to see the condition to render a good advice , anyway you do this is better than nothing at all , 

[Matthew Duncan]

19 hours ago, Lawdog Dago Dom said:

How big is too big for a gun safe on a first floor? No basement, just a crawl space. Home built in 1989. Joists appear to be 16" on center.

 

One big safe or two smaller ones?

 

Not even close to being an engineer, so all feedback is welcomed.

 

Thanks,

LDD

What size are the floor joists?  2x6?  2x8?  Solid or manufactured joists?  Makes a big difference.  Simpler just to add blocking (as others have suggested) in the crawl space.

[Cusz M. Dutch SASS Life 55326]

Your house is over designed for the most part.   I really doubt that a large deep freeze full of meat would be any less  of a load per square foot then your gun safe. 

[Hashknife Cowboy]

buy smaller and disperse the weight.

[J-BAR #18287]

Just curious, when you invite some of us older, heavier cow folk over for a party, are we gonna hafta step on a scale at the front door??  

[Michigan Slim]

52 minutes ago, J-BAR #18287 said:

Just curious, when you invite some of us older, heavier cow folk over for a party, are we gonna hafta step on a scale at the front door??  

He would just wave me right in.....

[Lawdog Dago Dom]

8 minutes ago, Michigan Slim said:

He would just wave me right in.....

 

Slim is correct.

But, to not stress our friends that attract a bit more gravity than the others, there is a heated outbuilding with a concrete floor that will accommodate a party into the wee hours. For Shortcake and me that is anything after 9pm. Y'all just pick up and lock up before ya go.

[J-BAR #18287]

12 minutes ago, Michigan Slim said:

He would just wave me right in.....

Well, my point is, you get four or five guys huddled in one spot telling a joke, that’s 800 to 1000 lbs, and who thinks twice about that?

[Chancy Shot, SASS #67163]

On 12/13/2020 at 11:03 AM, J-BAR #18287 said:

Well, my point is, you get four or five guys huddled in one spot telling a joke, that’s 800 to 1000 lbs, and who thinks twice about that?

There it is.....The point that is on point.   And that joker will be in the middle of the room, not next to a load bearing wall in a corner.

 

Chancy

[Baltimore Ed]

I would disagree on one point, that being placing your safe on an outside wall. Thugs have been known to cut through walls and pull safes out. Your house has pillars down the center [at least it should unless we’re talking a tiny house.] Would also suggest not putting it where it’s visible through a window that’s facing the street. Don’t advertise. My safe was 1400 lb mty, heaven knows what it weighs now. Hasn’t fallen through yet.