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  #1  
Old 08/14/2004, 09:47 PM
partagas partagas is offline
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How much weight can joists hold.

I live on the second floor of a house that is around 100 - 115 years old. I would like to put a 120 gallon tank that I have sitting in my garage. But my girlfriend ( Will I am also ) is concerned that the tank will be in the down stairs tenants and they will have a sky light into our place....... I checked the atitic and it looks like they run from center out. Also from the looks of them in the basement they look to be 2x6's. Since they are old, they are true 2x6. The tank would be against a wall that is in the same spot down stairs. So does anybody know if two ( If lucky three) joists next to a wall can hold the 1500 plus pounds? I would love to have the tank up and running, but I have to have proof that the floor can hold it.

Any help would be great.
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  #2  
Old 08/14/2004, 10:21 PM
BeanAnimal BeanAnimal is offline
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I am not an engineer but the only not of wisdom I would give you is this...

In modern contruction, the floors are stacked on top of each other. In other words, the joists ends rest upon a "wall" or "sill plate" BRick is then added as a veneer (it is not structural)

In many older homes the brick is the structure! It is the shell of the building, and the floors joists are nailed to stringers that are nailed or lagged to the brick.

In other words in new construction, placing a 10,000 pound barbell on the outside wall of a room is the strongest safest place for it. The weight is held by the exterior wall. In an older brick house, the weight is held by a stringer nailed to the wall. If the weight is moved to the middle of the floor, the weight is more evenly distributed to the other stringers on the other walls.

Ever notice how buckeled warped and uneven older building floors are? Sometimes inches difference! Do you *really* think that carpenters 80 years ago were that poor with a level or stringline?

IN any cae, I thinlk you will find that the floor will be just fine for the load you are talking about.

Just food for thought.

Bean
  #3  
Old 08/15/2004, 11:03 AM
partagas partagas is offline
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Thanks. I hope this will help my cause.
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  #4  
Old 08/15/2004, 12:25 PM
wasp9166 wasp9166 is offline
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put it his way, get 5 or 6 people that weigh close to 1500lbs accumulatively, have em stand where you want to put the tank, if they fall thru move, if not set it up
  #5  
Old 08/15/2004, 01:16 PM
partagas partagas is offline
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LOL, I like that idea. But how can I put it to my friends that I need 5-6 people that weight 300 lbs each to stand on this X for 20 minutes.

I just need to see if my floor can hold your fat A**'s.....

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  #6  
Old 08/15/2004, 01:34 PM
Saltz Creep Saltz Creep is offline
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Quote:
Originally posted by BeanAnimal
If the weight is moved to the middle of the floor, the weight is more evenly distributed to the other stringers on the other walls.
True, but then you place more stress on the middle of the joist and make it more prone too warpage.

It's really a toss up. Either move the weight closer to an outside wall and put stress on the joist hanger, or in the middle of the joist and take a chance on it warping.
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  #7  
Old 08/15/2004, 02:21 PM
wasp9166 wasp9166 is offline
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more than likely the joists should be sitting on top of the lower wall, and then the wall for the upper floor is on top of them, being that its old house i would verify, if this is the case you have nothing to worry about as long as you put the tank across the joists not parallel, if its connected to the outside wall via a nailer and joist hangars i wouldnt do it......
  #8  
Old 08/15/2004, 03:51 PM
BeanAnimal BeanAnimal is offline
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wasp may have said it clearer than I did.

Older homes that are not brick veener, rather brick construction usually used stringer or joist hangers.

In any case get your 5 150 pound friends and get them all to jump up and down at 1 time 10 or tell times in a row. You can figure out the acceleration and mass "landing" on the floor if you want... but I think if they don't collapse the house.. you will be ok.

As a side note. I was not allowed to set up my 75 in our apartment becasue the girl of the house was afraid of the same damn thing. Had to wait untill we bought this house...

good grief...

Bean
  #9  
Old 08/15/2004, 11:13 PM
sabalough sabalough is offline
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Dont forget about baloon framed houses (common pratice back then). The floor joists are comonly only nailed to the side of the wall studs. the wall studs in baloon framing run the entire hight of the house, so with a flash light in the atic you should be able to determine if this is the case.

Bolth my house(95 yrs old) and my brothers(120 yrs old) are framed this way. On the up side it makes rewiring alot easier.
good luck, do your detective work.

Steve,
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  #10  
Old 08/15/2004, 11:21 PM
daytona955 daytona955 is offline
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I am no expert, but after reading an extensive article about this subject before installing my 180 in my house, I found another thing to worry about is "shear" weight. Or the amount that will cause the suports to just snap where they are attached tot he frame. Supposedly you can get this information as it is supposed to be on file.
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  #11  
Old 08/16/2004, 12:20 AM
BeanAnimal BeanAnimal is offline
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"shear" is a form of catastrophic failure. I am not sure what modern numbers are... but they are HUGE. I would also think that even older stick built, brick construction, or baloon type structures will hold a substantial amount of weight before catastrophic failure occurs.

I have been at 2 seprate house parties on older homes...where the floor has givin way. Both times, the floor joists cracked, quite spectacularly and the floor sagged substantialy in the middle. Rather quickly I might add. Neither time did the people end up in the basement. Rather they just sorta went "wow" and kinda cleared the center of the room.

Both times it was due to joists twisting under the weight of 75 bouncing people and cracking.

My friend owns a bar (club) with 2x12 joists. We regularly have the floor flexing 4 to 5 inches in the center with the weight of 200 people dancing to modern music. Every year we add 10 tons of sand to the floor for a beach party. At one point some of the jousts did beging to split.... An H beam (pretty small) and some basement jacks... everything is good to go!

Last word... none of us can tell you without looking at the house....even then most of us could make an educated guess. If you are that concerned find a local engineer (most 84 lumbers or similar have somebody). A lot of times you can do some "brain picking" or even get a visit for free or next to nothing.

Bean
  #12  
Old 08/16/2004, 07:21 AM
Ira NZ Ira NZ is offline
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If all else fails, see if you can talk the people downstairs into letting you put a nice, tastefull(of course) column in the middle of their living room under the tank. I'm sure if they're fish people they'll understand.
  #13  
Old 08/16/2004, 12:23 PM
jeffbrig jeffbrig is offline
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Quote:
Originally posted by BeanAnimal
Every year we add 10 tons of sand to the floor for a beach party.
Aragonite or silica-based?
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  #14  
Old 08/16/2004, 03:42 PM
wasp9166 wasp9166 is offline
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southdown ,its cheap ya know
  #15  
Old 08/16/2004, 06:03 PM
BeanAnimal BeanAnimal is offline
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silica based construction sand :P
  #16  
Old 08/16/2004, 06:30 PM
daytona955 daytona955 is offline
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Haha my ole fraternity used to do that years ago. Fun stuff.
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