# What size of tank can a 3rd floor Apt support?



## nschluntz (Jan 14, 2008)

Greetings!

I currently have a 55G fish tank and I was hoping to upgrade to a larger size. Hopefully as large at 90G. However I live in a 3rd Floor Apartment. I've already asked the management, and they have no idea if the structure of the building can support that on a third floor.

I've heard the ratio is 10lbs for 1G of water, for aquariums. Does that sound correct?

I've had some tell me that its like a waterbed, and most apartments only allow waterbeds on the first floor.

Any advice or experience in this department would be great! Thanks!


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## Julie's Julies (Jun 11, 2007)

My dad is a structural engineer and gave me these specs: most apartment complexes are designed to hold 40lbs. per square foot on upper levels (outdoor balconies can hold 50lbs, but I don't think you want a fish tank out there!). 

The general guideline is to calculate 8-10lbs. per gallon of water. A standard 55-gallon tank is 48x12, which equals roughly 4 square feet of space. If you do the math, you are really pushing the weight limit even with the 55-gallon up there. While it is highly unlikely that your tank will go crashing through the floor to your lower neighbors, I would have to say that a bigger tank is really not a good choice right now. If you could relocated to a bottom floor, though, you should be able to upgrade without any problems. Or you could get a second tank to put on the other side of the apartment and split your inhabitants between the two (though I would recommend a 29-gallon rather than another 55).

Sorry to be the bearer of bad news, but best wishes in finding an alternative.


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## Amphitrite (Sep 8, 2006)

That's very interesting to learn Julie - I've never seen the actual specs posted before. I remember asking someone a similar question a couple of years back, and was told that weight didn't really matter that much.. expecially if you take into account how much a bath weighs when filled with water - and that doesn't go crashing through the floor.

I suppose one argument would be that the bath isn't constantly filled with water, and therefore isn't putting constant strain on the floor below. It's also possible (and I'm speculating here) that bathrooms are made with additional support in the floor to account for the weight.

I've also heard that as long as the tank is placed against an outside wall over more than one supporting beam that it should be safe enough.

I don't know but I wouldn't risk it ... just in case.


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## herefishy (Dec 14, 2006)

I'm not an engineer, but, I find it hard to fathom that an apartment building is designed to a 40# psf spec for the floor load. A full 18cf refrigerator weighs more that that. As would a full bathtub with a full grown man at 200#.

I have worked for architects and, although I worked the mechanical and service side most of my career, I believe that BOCA requires a load of a much greater as a minimum. I believe that the design criteria is in the neighborhood of 125# psf for a live load. Local jurisdictions may vary. A roof on a home weighs aproximately 35# per square foot to give one an example. This is higher in areas where snow loading is heavier.

I may be mistaken, as I don't have my reference books handy, but the theory is hard to accept. One way to circumvent this would be to place the tank along a wall that is consistant from top to bottom. A good example would be a firewall. This would minimize deflection caused by the weight of the tank. Shear may be a concern, but I think it would be minimal. We are talking 440-550lbs. The weight of 3 average men standing in a 4sf area.

A few years back, I had a 125g, 180g and a 300g all on the second floor of an apartment complex. None fell through nor did any plaster crack on the ceiling of the floor below me.


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## dodgeboy (Dec 10, 2007)

that must have been a large apartment or you had no furniture. hehe. must had to be site to see. did your neighbours think you were craszy? or jealous? i vote jealous.


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## Elahrairah (Feb 16, 2007)

I was thinking the same thing. 

I am on the 3rd floor and want to upgrade a 29 gal tank with a 60 gal one and I am scared to try...


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## nschluntz (Jan 14, 2008)

Well I know you should be okay with the 55G tank. I haven't had any issues. I'm still hesitant to install a bigger tank. I might try splitting them up like suggested and put some of them into a 29G tank.


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## 86T/A (Jan 18, 2008)

i agree with "herefishy." i would not be scared of it falling throw the floor i would be scared of the fact that something may happen to it and spill 90+gals. on a 3rd. floor. lol thats why most landlords wont let people have water beds above 1st floor. just my 2 cents


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