Structural engineers?

[exodus454]

I'm looking to put a 55 gallon aquarium in my bedroom on the 2nd floor of my house. My dad okayed the idea, as long as the floor will support it. After googling, I cant really find any math to do, so someone with experience is the next best thing.

The only thing that throws the ease of this ideas out of whack is the fact that the house is a ballon-frame structure which used to be a barn.

The basic 55g weighs about 600lbs when full. This is spread over a 4'x1' area under the stand, which is about 140psf. The aquarium would be placed perpendicularlly to the joists. I'd also put a piece of 1" thick wood underneath the stand to help spread the weight evenly, and it'd probably be cut about 2' wider than the aquarium to help get the weight over more joists. I'd probably build the stand itself 2' too wide as well, and have the piece underneath 2' longer than the stand.

So, stand =6' long, underlying piece of 1" thick wood = 8'.

The joists under the floor are 2x6's @ 16" on center. The flooring (no subfloor) is made of 2x8" boards which run the entire length of the room (so there are only about 15 or so boards to the entire room).

The aquarium would be placed on the inside of a partition wall which would leave the aquarium about 4" from the outside wall.


Can anyone help?

 

[Goosemaster]

Sound like a vector mechanics problem to me

 

[Sluggo]

The joists under the floor are 2x6's @ 16" on center. The flooring (no subfloor) is made of 2x8" boards which run the entire length of the room (so there are only about 15 or so boards to the entire room).

What you really need to determine is what distance the joists span. As of right now a 2x6 std&btr floor joist 16" OC spanning 12' would not even come close to passing building code for a live load.

http://www.sjgov.org/Commdev/cgi-bin/cd...s_Handout09?grp=handouts&obj=Handout09

I'm not a structural engineer, but I did stay at a Holiday Inn Express last night.

 

[exodus454]

I'll have to check on those joist measurements again, 6" sounds a bit short to me.. especially considering the floor on the first floor has joists made of 2x12's

Since the house is a balloon frame, I'd think they span from the front of the house to the back, which is probably 20'.

The whole balloon frame thing kind of has me puzzled a bit on this one.

 

[jagec]

Why do all that fancy calculating? 600 lbs really isn't all *that* much...just get two fat guys to stand on the board. If it holds, you're golden, if they fall through, videotape it and post it on youtube.

 

[BlueWeasel]

If possible, you'll need to verify the type of lumber (look for a stamp on one of the floor joists). Douglas Fir is much weaker than Southern Yellow Pine (SYP), and as such, the span lengths for 2x6's @ 16" OC are fairly short. If you've got SYP joists, then it might be possible.

I'm a structural engineer, and if you can wait until tomorrow, I can check the loading and deflections for your particular situation given the span, lumber type, and joist spacing.

If the container is only placed 4" from the supports (the outside wall), then bending moment and deflection aren't the problem -- it's shear. M and D would be the issues if the full 600# load was placed at the midspan (equal distance from the end supports).

 

[exodus454]

Originally posted by: jagec
Why do all that fancy calculating? 600 lbs really isn't all *that* much...just get two fat guys to stand on the board. If it holds, you're golden, if they fall through, videotape it and post it on youtube.

It may hold while the fat guys are there, but what about them standing there for years on end?

Not the same.

 

[exodus454]

Originally posted by: BlueWeasel
If possible, you'll need to verify the type of lumber (look for a stamp on one of the floor joists). Douglas Fir is much weaker than Southern Yellow Pine (SYP), and as such, the span lengths for 2x6's @ 16" OC are fairly short. If you've got SYP joists, then it might be possible.

I'm a structural engineer, and if you can wait until tomorrow, I can check the loading and deflections for your particular situation given the span, lumber type, and joist spacing.

I'm not sure of the type of wood ('ll get a picture up to see if you can tell), but its a very fine-grained wood with no visible knots where I have access to it. I'd say the span of the joists is about 20'.

This part of the house is quite old, the other half was added on in the 50's.

 

[jagec]

Originally posted by: exodus454

Originally posted by: jagec
Why do all that fancy calculating? 600 lbs really isn't all *that* much...just get two fat guys to stand on the board. If it holds, you're golden, if they fall through, videotape it and post it on youtube.

It may hold while the fat guys are there, but what about them standing there for years on end?

Not the same.

Umm, are the beams rotting? Are you emptying and refilling the aquarium over and over to impose a cyclical load? How exactly is it any different?

 

[exodus454]

Originally posted by: jagec

Originally posted by: exodus454

Originally posted by: jagec
Why do all that fancy calculating? 600 lbs really isn't all *that* much...just get two fat guys to stand on the board. If it holds, you're golden, if they fall through, videotape it and post it on youtube.

It may hold while the fat guys are there, but what about them standing there for years on end?

Not the same.

Umm, are the beams rotting? Are you emptying and refilling the aquarium over and over to impose a cyclical load? How exactly is it any different?

No, but the floor can start to bow after some time with that amount of weight on it in one spot, which can eventually lead to total failure.

 

[JinLien]

are there any walls that support the beams/joists.

According to the California Code of Regulations 4x6 Douglas fir @ vertical can handle 450 lbs load at center of beam.

My home is from 1973 & it have 4x12 @ 48" center, and I have had as much as 1500 lbs or more (books) and the spans at the longest point are 12'. I have measure the flex of empty room to full room of books and the floor flexes about 1/2".

The problem is not that your floor couldn't handle the load, because 600 lbs is nothing for your floor because the weight is spread out over many joists, however your floor will flexes/bounce when you jump or walk on it.

You can run 2x12" fir (or laminate) beams across the joist to give it more strenght with 4x4 or 6x6 supporting colums if it is a concern.

 

[BoomerD]

If you put it against a load-bearing wall, you should be fine. As mentioned, 600 lbs isn't much actual weight, and should be easily handled. (actually, if you figure 10 lbs/gallon, you'll be closer to the actual finished weight) If you were talking about a big aquaruim, then maybe you'd have problems, but a 55 is barely big enough to not be considered a nano... Not a bad starter size though, although personally, I'd recommend a 75 over a 55. The extra depth (front/back makes a ton of difference in aquascaping, without being so big that it becomes a daunting task trying to take care of it.

 

[jagec]

Originally posted by: exodus454

Originally posted by: jagec

Originally posted by: exodus454

Originally posted by: jagec
Why do all that fancy calculating? 600 lbs really isn't all *that* much...just get two fat guys to stand on the board. If it holds, you're golden, if they fall through, videotape it and post it on youtube.

It may hold while the fat guys are there, but what about them standing there for years on end?

Not the same.

Umm, are the beams rotting? Are you emptying and refilling the aquarium over and over to impose a cyclical load? How exactly is it any different?

No, but the floor can start to bow after some time with that amount of weight on it in one spot, which can eventually lead to total failure.

If you don't hear any squeaking or groaning when the fat guys are on it, it won't fail. That's how you gauge your margin of safety with wood.

It won't bow enough to cause trouble, if you don't hear the distinctive sound of getting near the failure point when applying a greater "test" load. Now, if you hear it groan when you install the aquarium...that's risky. Still, most people vastly underestimate their safety margins...just look at how much weight gets successfully transported in a third-world truck or bus as compared to here.

 

[exodus454]

Originally posted by: JinLien
are there any walls that support the beams/joists.

There is one parition wall right in the center of the joist span, which is pretty heavy duty but it doesnt go all the way to the basement. I'm sure that could help with any flexing if it were to occur.

I dont mind the floor flexing when I walk on it either, since its a bedroom there is very minimal foot traffic in here. It wont really bother me if that happens, as long as I'm not looking at a possible total structural failure.

Originally posted by: BoomerD
Not a bad starter size though, although personally, I'd recommend a 75 over a 55. The extra depth (front/back makes a ton of difference in aquascaping, without being so big that it becomes a daunting task trying to take care of it.

I'd love to get a 75, I have a 55 freshwater downstairs in the livingroom and would love to have the extra depth. But there's no way I could really convince my dad to let me put a tank of that size on the 2nd floor.

I could put a 75 downstairs and move the 55 upstairs, but thats so much work I figured a 55 up here would be a good size for a delve into saltwater reefkeeping. Not too small, but not too big.

Someday!

I know when I move out, I'm looking for a 1st floor apartment with concrete floors

 

[JinLien]

Originally posted by: jagec

Originally posted by: exodus454

Originally posted by: jagec

Originally posted by: exodus454

Originally posted by: jagec
Why do all that fancy calculating? 600 lbs really isn't all *that* much...just get two fat guys to stand on the board. If it holds, you're golden, if they fall through, videotape it and post it on youtube.

It may hold while the fat guys are there, but what about them standing there for years on end?

Not the same.

Umm, are the beams rotting? Are you emptying and refilling the aquarium over and over to impose a cyclical load? How exactly is it any different?

No, but the floor can start to bow after some time with that amount of weight on it in one spot, which can eventually lead to total failure.

If you don't hear any squeaking or groaning when the fat guys are on it, it won't fail. That's how you gauge your margin of safety with wood.

It won't bow enough to cause trouble, if you don't hear the distinctive sound of getting near the failure point when applying a greater "test" load. Now, if you hear it groan when you install the aquarium...that's risky. Still, most people vastly underestimate their safety margins...just look at how much weight gets successfully transported in a third-world truck or bus as compared to here.

That why many trucks/buses rolled/broke their axels in third world countries. And, there is a greater amount of death per earth quake in third world countries than the US/California.

 

[Greenman]

Sounds like it's a very old house, so be carfull. I've seen floor systems overspaned by a factor of two in some old houses.
Here on the West coast, 40# per square foot live load (the stuf and people in your house) is what we build. So a 550# tank of water over an area of 4 sf is over the limit, but as long as the rest of the system isn't at it's max load it will hold just fine, and won't sag.
But in what was once an old barn, I wouldn't place that much point load on the floor system unless I was certin of the framing. 2x6 @ 16" O.C. with a 20' span is a very weak floor, I'm talking weak enough for a catastrophic failure. And if it is indeed ballon framed walls, the floor system is prolly only nailed to the studs, another poor connection. As others have said, near an outside or bearing wall is the best bet, it's far and away the strongest part of the system.

btw, I'm a building contractor with 30 years in the trades, so I know a little about home building.

 

[Soccerman06]

Think about it like this, theres 576 sq inches there holding 600lbs. Each sq inch needs to hold 1.04167lbs. I think putting a 20lb barbell on one end and if the floor caves in, then you cant put a tank there, if it doesnt cave in, your good.

 

[exodus454]

Originally posted by: Soccerman06
Think about it like this, theres 576 sq inches there holding 600lbs. Each sq inch needs to hold 1.04167lbs. I think putting a 20lb barbell on one end and if the floor caves in, then you cant put a tank there, if it doesnt cave in, your good.

That would be a good test to see if it would end up punching through the floor, but wouldnt be good test of overall strength I don't think.

 

[JinLien]

There is one parition wall right in the center of the joist span, which is pretty heavy duty but it doesnt go all the way to the basement. I'm sure that could help with any flexing if it were to occur.

The wall isn't a load bearing wall but it could be use to tie the walls together and spread the weight making the ballon frame stronger. (honey comb/strut effect)

 

[alphatarget1]

Wood is better for short term loading btw.

It'll be better if you don't put it in the middle of the room. You still get a lot of shear though. I'd do some calcs with the wood code before I do anything. What is the span length for the 2x6 @ 16" O.C.? It seems awfully small honestly.

 

[alphatarget1]

Originally posted by: JinLien

There is one parition wall right in the center of the joist span, which is pretty heavy duty but it doesnt go all the way to the basement. I'm sure that could help with any flexing if it were to occur.

The wall isn't a load bearing wall but it could be use to tie the walls together and spread the weight making the ballon frame stronger. (honey comb/strut effect)

It doesn't go all the way to basement? So the wall is being supported by floor joists below or something?

It'd be nice to see floor plans!

 

[exodus454]

Originally posted by: alphatarget1

Originally posted by: JinLien

There is one parition wall right in the center of the joist span, which is pretty heavy duty but it doesnt go all the way to the basement. I'm sure that could help with any flexing if it were to occur.

The wall isn't a load bearing wall but it could be use to tie the walls together and spread the weight making the ballon frame stronger. (honey comb/strut effect)

It doesn't go all the way to basement? So the wall is being supported by floor joists below or something?

It'd be nice to see floor plans!

Yes, its being supported by the floor joists on the first floor, and then there's another partition wall underneath that in the basement.

I cant today, but tomorrow I can go get the floor plans from the town if needed.

 

[dangereuxjeux]

For your own sake, please listen to the structural engineer and not the intuitive responses from those simply thinking about psf. Structural materials (like your floor joists), can fail in several ways, not just in the simple bearing capacity that most of the analogies here are considering. Your floor joists need to be able to handle the loads in vertical and horizontal shear, bending, deflection, etc.

 

[exodus454]

Here's a few shots of the part of the floor I have access to. Used to be a heat vent in the floor.

http://img.photobucket.com/albums/v260/exodus454/IMG_7931_R.jpg
http://img.photobucket.com/albums/v260/exodus454/IMG_7932.jpg

 

[BigJ]

Is that roll-on glue in that second picture?