Max. ammo weight on upper floor? 3 or 2 cans thick?

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Ignition Override

New member
A friend recently cautioned me about having three layers of filled (with .303/8x57 etc) .50 cal ammo cans in an upstairs room.
So I spread them out in order to have them only two cans deep.

This home was built about ten years ago and newer homes down south do not seem nearly as strong as they were approx. thirty years ago.

There is no possibility of weighing these cans, so as an approx. structural limit what is considered a reasonably safe maximum with filled .50 cans for long-term storage?
 
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FrankenMauser

New member
Generally, 40 lb/sqft is considered maximum live load on a residential floor with any kind of wooden support.

Keep in mind, however, that that is calculated with the load evenly spread over the entire length of the floor joists - wall to wall (or more) - not as a point load or localized load.

If you wouldn't put an 800 lb safe there, I wouldn't be stacking full ammo cans; and even a single layer (though probably safe) may be too much...
 
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SaxonPig

New member
Do you really think someone can answer this question? YOU don't know how much weight you have so how can anyone reading this take a guess? (Really? Impossible to weigh the cans?) Nor does anyone reading this know how the house is built or the current weight on the support system.

Three layers stacked? Over the entire floor of the room? Or ten square feet of it? Are there 10 ammo cans? Or 100? We have no way of knowing.

You don't specify weight or number of cans being stored. We don't know how much weight we are discussing.

Couldn't you just store the cans on the ground floor and relax? Why do they need to be upstairs, anyway?
 
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Aguila Blanca

Staff
FrankenMauser said:
Generally, 40 lb/sqft is considered maximum live load on a residential floor with any kind of wooden support.
Click to expand...
According to the International Residential Code (for houses), the minimum allowable floor load for habitable rooms other than for sleeping (you wonder why they don't just call them "bedrooms," but builders play all kinds of games with room names to try to beat some code or other) is 40 pounds per square foot. For sleeping rooms and for attics served by a fixed stair it's only 30 psf.

If you keep the load near an area that has a wall or a beam directly below, you can go higher. The weakest part of a wood floor is the area toward the middle of each span -- roughly the middle third.
 
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Uncle Buck

New member
You could put a piece of plywood across the floor to help spread out the load weight also. But why not just store them in a different location if it is a concern.

I understand some people live on the second or third floor of a house (apartment buildings).
 
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natman

New member
I've got a 50 cal can half full of 30-06 that weighs 15 pounds on my bathroom scale. Full it would weigh 30 pounds. It's roughly 6x12" so let's call it half a square foot. That's 60 pounds per square foot. Two layers would be 120 and three deep would be 180.

So 2 deep would be three times the rating of 40 lb/ft^2 and 3 deep would be 4.5 times.

Move it downstairs.
 
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Aguila Blanca

Staff
Again, the code requirement for sleeping rooms is only 30 psf, not 40, and any upstairs room in a single-family house is likely to be a sleeping room (except the bathroom(s).

BUT ... that's 30 psf over the entire floor area. Even though it's a bit small compared to reality, for simplicity of math let's assume the room is 10' x 10', so that's an area of 100 square feet. Multiply that by 30 and you get a total weight of 3,000 pounds. Using Natman's estimate of 30 pounds per can, that's 100 cans.

Again, BUT ... that's assuming they are spread out fairly evenly around the floor. Stack them all at the mid-point of the supporting floor span, and you've got a problem. Conversely, if a wall in the room lines up over a wall downstairs and the cans are stacked along the wall, there's probably nothing to worry about. There are engineering formulas that convert from a uniform (meaning per square foot) load to a concentrated (pile it all in one place) load. I studied some of that in school, but that was more than 40 years ago and, when you don't use it, you lose it.

As has been noted, there really isn't enough information provided to allow anyone to answer the question at all knowledgeably. I'll just mention that there's a reason why I don't put a gun safe on the second floor of my house.
 
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southjk

New member
I feel like I'm missing something, which is not unusual. How can code be 40lbs per sq ft? I weigh almost 200 and am able to stand in a space measuring 1 sq ft. Does that mean I'm in danger of falling through the floor. What about if I'm in bed upstairs? My 200 lbs and the weight of the bed spread out evenly to the four legs of the bed is more than 30 lbs to each leg. :confused:
 
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