Largest possible tank

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Bender

Aquarium Advice Regular
Joined
Dec 16, 2008
Messages
83
Location
Atlanta Ga
What is the largest Freshwater tank seenin homes? I know technically there would be no limit on how large a tank could be assuming you could house it and filter it....But I dunno guess im looking for pics of some sort???
 
I saw a pic of a 225gallon one I think o_O

Wish I had that, tho it'd probably fall through the floor xD
 
OMG!!! Wow if I had room for that then I would so buy it and swim with my koi Aiko and Akiko they are identacal except Aiko is bigger and they are inseperable.
 
I wouldn't put anything larger than a 240g above a first floor personally. I've seen 300's and I know you can get 480-500 or so.
 
Even on a second floor, so long as you provide the proper supports, there isn't any reason you can't have a 500 to 1000 gallon. While the exact numbers depend upon how tall the 1st floor is, a standard 4x4 is rated for something like 4,000 or 5,000 pounds. Properly installed, you would only need as few as 4 - 4x4s to support he weight of a 1000 gallon tank.

Actually, our 2nd floor garden tub holds something like 200+ gallons. Our builder simply studded in a closet in the downstairs bathroom under the tub to provide additional support.

In the summer, we safely place a 500+ gallon swimming pool on our deck that is 8 feet off the ground. Of course the deck's primary supports are 6x6s, I've reinforced the joists and the studs on that wall of the house, and added a pair of 4x4 s directly under the pool.
 
I'm talking about an average house that has been already built as far as supporting a tank of up to 500g. Certainly it can be done with different materials like 4 by's or even steel and concrete. How many houses have steel reinforced concrete floors?
 
I'm talking about an average house that has been already built as far as supporting a tank of up to 500g. Certainly it can be done with different materials like 4 by's or even steel and concrete. How many houses have steel reinforced concrete floors?

Well, let's start over in our consideration of what the typical house. Modern building codes require that every floor support a minimum of 40 pounds per square foot. 60 pounds per square foot is more typical, with 100 pounds per square foot being on the high end.

Next, consider a waterbed. That's one of those pieces of furnature that people begin to wonder if their house can support the weight of that piece of furnature. Well a typical king size water bed can weight around 2,000 pounds. But that weight is spread over an area of over 75 square feet. The net weight of the water bed is about 25 pounds per square feet. That's well below the 40 pounds per square feet standard, so any modern house should feel safe placing a waterbed in the bedroom.

Next, consider a 55 gallon tank. The tank is going to weight around 500 pounds or more. But it occupys only 4 square foot of floor space. That makes of a net weight of about 125 pounds per square foot. So even with just a "small" 55 gallon tank, you are already exceeding the load limit of an extreamly well constructed floor. Of course that just means that you can NOT fill your room with 55 gallon tanks. A single 55 gallon tank is not going to cause your floor to collapse. But in a 12ft x 15ft room, a single 55 gallon fish tank can represent about 10% of the total weight thr room can safely support.

So even with a simple 55 gallon tank, you have to begin thinking seriously about support. At a minimum, you are going to want the tank near a wall and not in the middle of the room, and you are going to want to ensure that the tank weight is spread across as many floor joists as possible.

But given the numbers I just reviewed regarding a 55 gallon tank, I would say that anything larger than a 55 gallon tank and you have to either consider placement of the tank VERY CAREFULLY, or you have to reinforce the house in some manner. That reinforcement can be as simple as installing sister floor joists to the existing joists, or it might require framing some sort of support under the floor.

Framing in a support is VERY doable if your house has either an unfinished basement on concrete, or has a crawl space over dirt. In the case of a crawl space, you can add supports the way you would for building a deck (4x4s on either a poured footer, or deck blocks). In the case of an unfinished basement, you just have to have the practical space to frame in something like a closet or storage space under the tank. Basically, you build a wall under the tank. Standard stud walls, especially if you frame with either 2x6 or doubled up 2x4s can hold LOTS of weight. The major limitation in wheither a floor can hold 40 or 100 pounds per square foot is the floor joists, not the walls. I would therefore claim that if a 15ft x 12ft room can hold as much as 60,000 pounds with the right joists, that means the walls can support about 1,000 pounds per linear foot. So a 4ft x 18in closet framed in a basement under a fish tank could support a tank upto around 10,000 pounds, and that would be equivilent to a 1,000 gallon fish tank.

So if you have the practical space in the basement to install reinforcement walls, the typical home owner is only limited to the size fish tank his budget can affort. Because when you start talking about fish tanks greater than 100 gallons, the cost of the tank is going to be more than the cost of building a support wall under it. So your only true limit is where you can build support walls, OR your limitation is going to be in the height of your fish tank. The taller the fishtank, the higher the pounds per square foot load is going to be.

So consider a 600 gallon tank. I've seen tanks about this size in commercial applications. For those that know about them, Guthrie's used to have salt water fish tanks in all their resturants. These tanks were about 6 feet long, 3 feet wide, and 4 feet deep. As 600 gallons, the weight would have been about 6,000 pounds, or 350 pounds per square foot. Given that a house wall can be made to support 1,000 pounds per linear foot, and such a tank has 18 linear foot around its base, a modern house can easily install a 600 gallon fish tank if they have the basement room to build a standard load baring wall under the tank.

Based on that last set of measurements, I would say that the only thing limiting the typical home owner is that he can't have a fish tank any TALLER than about 8 feet tall without having to resort to EXTREAM measures to support the tank... again, assuming there is the practical space in the basement to build a support wall.
 
Excellent information HooKooDooKu. Did your calculations, though, include necessary safety factors, or were you working off of pure breaking strength of the materials listed?

Also, others, if you are going to look into modifying your home for tanks, make sure to verify #'s given with your *local* building codes. What is allowed/required will vary widely just from one side of the country to the other... not to mention for codes in other countries.

For a large tank, my big suggestion would be to make sure that you have cross braced joists in the floor the tank is sitting on. Not only will this remove any springiness from the floor, it will prevent permanent warpage of joists the tank is sitting on over time. Of course, the only way to do this, though, is if you have an unfinished ceiling on the level below, or you are willing to rip out a lot of ceiling.
 
HooKooDooKu, I think you have misunderstood the 40 lb/sq ft building code.

That code does not refer to a point load on the floor, rather, it refers to the entire floor itself. <And it applies only to residential wood framed houses.> Strictly speaking, you calculate the load by the span of the joist multiply by the width of the room across the joist, and assuming a static load EVENLY distributed across the entire floor. So, if your joist spans 12', and you have a 12' room, then the load for the room is 12*12*40 = 5760lb. Note that this load rating has to support any structures above the room - so your load capacity of the room is reduced if you have a load bearing wall in the span, a heavy roof, snow on the roof, etc.

When placing fish tanks, you cannot assume even distribution of load. So people usu. calculate by using the width of the tank x joist span. So in the 12x12 room, placing the tank across the joist, you should be able to support 4x12x40=1920 lb. So even if you have a lot of other loads in the span, a 55 gal should be OK in that situation. So with careful placement, you should be OK with up to ~75 gal. <Let's use about 1/2 the rated load to be conservative, to account for the weight of the roof, & other things you have inside the room.> Anything more, & you need a structural analysis of your house.

BTW - a king size water bed is not necessarily OK without support. Our building code actually requires structural supports for water beds & jetted tubs & the like.

Anyway, I think that for the typical wood frame house, a 75-100 gal is about the limit for the upper floors without reinforcement. You can put as large a tank as you like in a basement concrete slab, as long as the slab is supported below frost line so it won't shift.
 
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Excellent information HooKooDooKu. Did your calculations, though, include necessary safety factors, or were you working off of pure breaking strength of the materials listed?

Also, others, if you are going to look into modifying your home for tanks, make sure to verify #'s given with your *local* building codes. What is allowed/required will vary widely just from one side of the country to the other... not to mention for codes in other countries.

For a large tank, my big suggestion would be to make sure that you have cross braced joists in the floor the tank is sitting on. Not only will this remove any springiness from the floor, it will prevent permanent warpage of joists the tank is sitting on over time. Of course, the only way to do this, though, is if you have an unfinished ceiling on the level below, or you are willing to rip out a lot of ceiling.

I didn't want what was already a long post to get bogged down in too many details. The actual details of the the 40 pounds per square foot are not based on breaking strength but actually a percentage of deflection in the wood. I do not recall the exact details and numbers, but it works something like this: If a floor is spanning a distance of 10 feet, the floor joists must be sized and spaced such that a 40 pounds per square foot load applied to the entire floor will not cause the center of the floor to deflect by more than 1/4". Again, I don't recall exact numbers, but that distance of 1/4" is actually some mathmatical formula based on the length of the span, and the desired pounds per square foot load.

The discussion of the wall strength is based on the notion of the upper end of typical floor strength designs is about 100 pounds per square foot. I do NOT know if it would take 2x4 studs on 18" centers, 2x6 studs on 18" centers, or doubled up 2x4 studs on 18" centers. I'm just calculating backwards from the notion of being able to build a floor that can hold 100 pounds per square feet in a typical sized room.
 
HooKooDooKu, I think you have misunderstood the 40 lb/sq ft building code.

That code does not refer to a point load on the floor, rather, it refers to the entire floor itself. <And it applies only to residential wood framed houses.> Strictly speaking, you calculate the load by the span of the joist multiply by the width of the room across the joist, and assuming a static load EVENLY distributed across the entire floor. So, if your joist spans 12', and you have a 12' room, then the load for the room is 12*12*40 = 5760lb. Note that this load rating has to support any structures above the room - so your load capacity of the room is reduced if you have a load bearing wall in the span, a heavy roof, snow on the roof, etc. ...

Thanks for including the clarification. I do understand that the 40lb/sqft is a distributed load, and all my calculations were based on that. But in re-reading my post, I see that I did omit that detail in the post.

And yes, everything was based on a wood frame house...

Thanks for the extra detail.


And just to make sure things are clear... all my numbers are general estimates, some of them making educated guesses based on what little I do know about wood framed houses. I'm not a house designer, nor do I know all the details regarding building codes. But I did research the subject enough so that I could reinforce my deck and feel comfortable with my children playing in a 500 gallon "kiddie" pool on a deck 8 feet off the ground.

And so I whole hartedly agree that basically with your basic summary...
which I would summerize this way...

Anyone installing a tank larger than what you can pickup at the local PetSmart (or similar store) is going to need to look into reinforcing their floors.
 
Even a seasoned House designer (architect) will tell you the most math they know is the phone number to their structural engineer ;P

Yea, when I was studying Engineering in collage, we had at least one teacher that phrased it something like this...

"An architect determines what color the light switches are, and engineer determines how to hold the building up."
 
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