Reef nutrition

Weight concern with new tank

DurTBear

DurTBear

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Hey guys...so I'm getting really excited since I was told my new tank should be done by the end of this week. But now I'm getting concerned about the weight issue again. I live in a relatively new condo in SF which was built primarily with concrete. I was reassured in talking to various people that my floors could handle the load of a 120 gallon tank. But I recently spoke to a construction buddy of mine and he is having serious concerns. He said the load for standard concrete floors in a building like a condo is 100 lbs per square foot. I would be well over that number if I assume the tank and water is about 1400 lbs. With a 9.2 square foot footprint, this comes out to about 152 lbs per square foot. And that doesn't even factor in equipment and stand. I'm guessing with a sump, stand and equipment, the total weight could be close to 2000 lbs. Trying to figure out if the wall it will be closest to is a load-bearing wall as this may help. But do you guys have any advice, concerns, suggestions, etc?
 
Well, no expert here nor close to trying being one but that load (100lb/sq. ft) seems out of wack for concrete construction and being in earthquake country makes no sense.
 
Yeah not an expert here... although I did stay at a holiday inn express last night! 100 pounds per square foot? I would more than double that capacity just by standing still, not to put your buddy down but I'd get a second opinion on that number, 100 PSI maybe, but not 100 PSF
 
Yeah...to me 100 pounds per square foot seems very low to me as well. Maybe he meant PSI like you said. But I'm just trying to err on the safe side here. 2000 pounds is a lot regardless so I just want to make sure it's safe.
 
No I'd totally err there :D But you literally could not have any sort of party (no dancing either) with people, otherwise your whole floor would be at danger to collapse if that were the case.
 
sfsuphysics said:
No I'd totally err there :D But you literally could not have any sort of party (no dancing either) with people, otherwise your whole floor would be at danger to collapse if that were the case.
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That's true. But he was saying something about dead load (which the aquarium falls under) and live load (which would include people). I think the problem might lie in the fact that that much weight is sitting in a small area 24 hours a day whereas a party would only have a lot of people for a matter of hours.
 
JAR said:
Clearly you worry too much!
LOL :D
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Yeah, I was fine until I spoke to my friend today. I know you said it should be fine. But for some reason I'm worried about it again. Just want it to be safe, you know?
 
There are other factors.
If you put the tank in the middle of a big room that has no supports or walls under it your dead load becomes more of an issue.
Maybe just put it on wheels so it becomes a live load. :D
If you are truly worried about it I could put you in touch with a structural engineer who would come out and take a look. It might cost like $100-200 for that.
 
The tank will definitely be going against a wall (maybe even a load-bearing wall but I need to confirm). Might need to talk to your structural engineer friend. Will do a little more research before deciding on that. But would the structural engineer know the answer just by looking at the building or would they need blueprints, specs, etc.? Trying to not involve the building managers as much as possible since the new association rules say I'm not technically supposed to have a tank this big.
 
He could just look at it.
The problem with this guy is that he talks real loud so you may want to ask him to whisper the conversation.
Clearly if it is going against an outside wall it would be load bearing.
You can go in the basement/garage and look for columns and beams for the other load bearing walls.
Your friend is probably close with his #'s but the failure #'s are usually more than twice the rated loads.
 
My guess is that up against the wall, with concrete floors, you will be just fine.

Yet I would strongly advise actually paying a structural engineer for a written opinion.

Two things to worry about:

1) Worst case scenario, and LIABILITY.
Think earthquakes / Shoddy construction of your floor.
Basically, there is a very low, but non-zero chance of it falling through the floor and doing major damage, if not injury.
Guess who they will look at first, regardless of real cause.
And if you knowingly/secretly violate the weight standards, it could be considered deliberate negligence.
As such, insurance companies may not pay, and you could be really screwed.

2) Condo associations and neighbors.
What happens when the downstairs neighbor makes an official complaint?
If you have a nice written opinion that it is safe, everyone might be happy.
Otherwise, the condo board is unlikely to take a risk, and will simple force you to get rid of it.
All those years of effort...
 
Yeah, maybe it's best if I get a pro to come in and properly assess the floors. I just want to make sure it's safe because I don't plan on letting the association know simply because they have an unreasonable tank limit of 20 gallons. I currently already exceed that with my 40 gallon tank.
 
Yes, actually telling people about it seems like a bad idea.
20 gallon limit is a joke, and confirms that they are paranoid.
Hey, right now, houses are cheap, and rates are low .... Simple. :)
 
Durwin

First with my experience in the construction world (over 15 years) I have never seem nor found a building code nor a concrete company that would carry concrete that is less than 2500 PSI (2500 Lbs Per Square Inch) and I am talking to a concrete slab like a driveway that is only 4 inches thick.

With that in mind remember that the concret slab between floors in apartment/condo, parking garage, commercial buildings would be at least 12 inches thick is not more.

Therefore the weight of your new tank with water, livestock, equipment, stand, etc. should be not a problem.

So word of advise DO NOT WORRY TOO MUCH AND JUST DO IT.
 
The compression strength of concrete is dirrerent than what a concrete floor can span. Compression has a solid base underneath. The load of a floor in a building has more to do with the reinforcement. This can vary for buildings. You could start by looking at the relevant building code for the time your building was completed for multi tenat residential.
I am a landscape architect and have done several projects similar to the building you live in. Most of our work is done on the level directly over the garage (podium level). For this area we can usually place 2.5' of soil before the structural engineer without getting the ire of the structural engineer. Soil weighs 120 lbs per cubic foot when wet. But on higher levels of the building we have been held to 12", sometimes less.
I also think if you where near a load bearing wall that you would be fine since the walls are designed to carry so much more, but you ahold consult with a Strutural engineer. Rygh is right you, you should cover yourself given the condo situation.
 
rygh said:
Yet I would strongly advise actually paying a structural engineer for a written opinion.
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I'd be surprised if one would provide anything in writing without first seeing structural drawings for the building.
 
Mr. Ugly said:
rygh said:
Yet I would strongly advise actually paying a structural engineer for a written opinion.
Click to expand...
I'd be surprised if one would provide anything in writing without first seeing structural drawings for the building.
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Same here. Everyone I have dealt with in fact required them prior to any consultation :(
 
Orion said:
Durwin

First with my experience in the construction world (over 15 years) I have never seem nor found a building code nor a concrete company that would carry concrete that is less than 2500 PSI (2500 Lbs Per Square Inch) and I am talking to a concrete slab like a driveway that is only 4 inches thick.

With that in mind remember that the concret slab between floors in apartment/condo, parking garage, commercial buildings would be at least 12 inches thick is not more.

Therefore the weight of your new tank with water, livestock, equipment, stand, etc. should be not a problem.

So word of advise DO NOT WORRY TOO MUCH AND JUST DO IT.
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Yeah, I totally wasn't worried when I originally talked to a few people and went ahead and placed the order of the tank. It was only until a couple days ago when a construction buddy voiced his concerns. I also thought about the two-story garage on the bottom two floors of my building and how it holds 50 cars or so on the second floor. In my gut I think it's fine but I guess I just want to be 99% sure that it's completely safe.
 
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