# Tank weight in my new house



## ambull (Jun 14, 2005)

Okay, at the risk of sounding like a dumb ass.......

I was all set to buy a 215 gallon tank for my newly built house today. A tank that size weighs over 2000lbs. Builder came back and said my house could not take on that kind of weight and that I would have to hire someone to reinforce the floors for that size tank. He said that to stay in warranty, I could not exceed 10lbs per SF. Now, this is where my dumbassness kicks in. I calculate that to mean that a 2FT X 6FT sized tank could only be 120lbs. Also meaning, that if I laid in that spot I would be too heavy and void the warranty in my house.

Makes no sense. Obviously I doing something wrong. Can someone help me figure out what the biggest tank I can fit in my new house is???

Ever grateful for your help......


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## AfricansRule (Aug 25, 2008)

10 lbs per SQFt is not alot, he might have ment 10 Lbs per Sq In? I would think you would be ok, IMHO. i would ask him if he meant Sq IN or Sq Ft, i would think he said Sq Ft.


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## Toby_H (Apr 15, 2005)

I think... the builder you talked to was either making it up as he went along... or at the very least meant, 10 lbs per square inch...

Just about everything in your hose weighs more then 10 lbs per sq ft...

For instance... YOU weight FAR more than 10 lbs per sq foot... I'd estimate the bottom of your feet to have about .75 sq foot (that is if you have big feet and are flat footed, less if you have normal feet)... so if you weight 150 lbs, then you apply 200 lbs per sq ft...

Sure you don't sit in the same place and apply constant pressure... but do some math on your refrigorator and then tell me if the builder was lying to you or not 

As him to show it to you in writting... as he is lying to you to avoid the slitest risk...

But you paid for a properly built home, and should get to enjoy the freedom of having such a home. If he has reason to doubt your home can hold the tank, it's that he knows his men didn't build your hose properly...

I'd guess he is simply willing to deny you the aquarium to avoid the slightest chance at a problem taking place... at his expense...


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## AfricansRule (Aug 25, 2008)

I figured it out to be around 13.88 Lbs per Sq In. Are u sure the footprint is 6Ft X 2Ft? If i were you, i would try to get a longer tank if you are able to and if you have the room for say a 8FT tank.


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## Toby_H (Apr 15, 2005)

Is the house slab on grade (concrete floor) or crawlspace?â€¦

With slab on grade, psi or psf matters quite a bit, but can hold far more than 10 psfâ€¦ even far more than 10 psiâ€¦

For exampleâ€¦ go out on your driveway and balance all your weight on just your heelsâ€¦ thatâ€™s about 8 sq inches touching the concreteâ€¦ so if you weight 160 lbs, thatâ€™s 20 psiâ€¦ do you think your driveway is about to break?â€¦ your house slab, just like your driveway, is 4â€


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## ambull (Jun 14, 2005)

I went back to the builder for clarity... and I am not on a crawl space but a finished basement... my dreams have been shattered tonight lol.... I'm embarrassed to admit that this tank was a big part of my plans for this house... I just never took into consideration the weight of the tank until I was about to place my order tonight...


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## Toby_H (Apr 15, 2005)

If we assume the tank, water, sand, stand, etc is 2,500 lbsâ€¦

And the tank is 6â€™ x 2â€™ (making it 28â€œ~30â€


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## Toby_H (Apr 15, 2005)

Rattsâ€¦ for the purposes of my above postâ€¦ crawl space and basements have the same functionâ€¦

We just donâ€™t have basements in my region so I always forget to include them as an option


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## ambull (Jun 14, 2005)

Toby I really appreciate all of your input.

For the sake of not misconstruing the words of my builders representative, here is an exact copy/paste of what he had to say:

"Our houses are designed with a dead load of 10lbs/SF and a live load of 40lbs/SF...my guess is that a structural engineer should be contacted to suggest how to beef up the floor system to hold the weight...so to answer his question, a standard house will not support a 1 ton fish tank without additional structural considerations."


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## Toby_H (Apr 15, 2005)

ambull said:


> "Our houses are designed with a dead load of 10lbs/SF and a live load of 40lbs/SF...my guess is that a structural engineer should be contacted to suggest how to beef up the floor system to hold the weight...so to answer his question, a standard house will not support a 1 ton fish tank without additional structural considerations."


My reply would be... "great, if you can just show me where it says that in my warrantee I'll leave you alone."

You need to see it in writing, meaning in the contract somewhere, not just â€˜his writingâ€™â€¦

As I described aboveâ€¦ you are a live load well over 40 psfâ€¦ your couch with no one on it is well over a 10 psf dead loadâ€¦

The guy is saying psf when me means psiâ€¦ which displays he has no clue what he is talking aboutâ€¦

I deal with contractors like that all the time... they say whatever makes their moment easier and removes the most responsibility from their shoulders...

My opinion is you paid full price and deserve full service... 
Well, in this economy I'm sure you got a bit of a discount, but I'm sure they appreciated the work!


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## Lunafish (Aug 9, 2009)

Check out this link for some information:

http://www.awc.org/technical/spantables/tutorial.htm

Look at Figure 2

Here are some quotes from that site:

"The house acts as a structural system resisting dead loads (weight of materials), live loads (weights imposed by use and occupancy), like snow loads and wind loads. Beams, studs, joists and rafters act as a structural skeleton and must be strong enough and stiff enough to resist these loads. "

"Examples of code-prescribed deflection limits and live load values are:

* Living room floors L/360 & 40 psf
* Bedrooms and habitable attic floors L/360 & 30 psf
* Attic floors with limited storage L/240 & 10 psf."

Notice that "Live Load" is not dancing or walking. But is all load *applied* to the floor. "Dead load" is the weight of itself, such as the drywall for the ceiling below, insulation, the floor joist, sub floor and your flooring.

Also notice that 40 Pounds per Square FOOT is the standard. Also notice that 50 PSF is for your garage!!!

The way I read things if your tank is not exceeding a pressure of 40 PSF on your floor then you are fine. As for some engineering solutions? My advice is a couple of sistered 2x6's and those steel poles people put under floors that are collapsing.

Matt


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## Toby_H (Apr 15, 2005)

Having red the article you linked, I see where you/it are coming from...

If you have a 20' x 20' living room... it can handle a live load of 20 x 20 x 40 = 16,000 lbs in the entire room... But that is NOT to say that each square foot of the room can only hold 40 lbs... as your average human being weighs well over 40 lbs and has a footprint that can stand within a square foot 

So according to the article linked above... if your living room is 20' x 20'... and your aquarium is 2,500 lbs... then you can have up to an additional 13,500 lbs worth of stuff in the room before your challenging the limits...


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## Lunafish (Aug 9, 2009)

Toby_H,

That is what I gathered from that article also. I sort of reached that conclusion when I saw 50 PSF for a garage floor. Since generally speaking car tires have a bit more weight then that when holding up the old family Lincoln.

Matt


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## fox (Jun 11, 2009)

The builder is right about 40 lbs psf live load for living areas and 30 lbs live load psf for sleeping areas and 10 lbs dead load . I design and build residential structures here in New York State and those figures are tatooed in my brain. Its the spans, direction and size of the joists you need to be more concerned with. *** boomed 3' worth of 4 x 12 gypsum board and laid it flat in the center of a room on the 2nd floor many more times than I care to remember, this weighs much more than that 210 G tank but the weight is spread over 48 sq.ft.

The biggest complaints we get from homeowwners is bounce in floors. Empty rooms bounce more so when furniture goes in the complaints lessen but you do not want your water shaking around in the tank when you move around in the room. Questions you should ask:

Which direction are your joists running
What size joist and what spacing on center are they
Span of the joist you want to place the tank on
Thickness of the sub flooring

Consider:

Placing the tank on an outer wall or inner bearing wall with a girder or wall beneath
And place it such that it rests on multuple joists, not parrallel to and only on 2 jst's.


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## Toby_H (Apr 15, 2005)

Matt,

Although I do Construction Material Testing for a living, there is not testing done in residential construction once the concrete is down. So I'm not thorough with my interior residential lingo... Thanks for sharing that link which cleared things up a bitâ€¦

In my ramblings above I described how/why it seemed â€œtotal weightâ€


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## 12 Volt Man (Sep 22, 2008)

I was going through the same thing when I was house hunting, only I was planning an Aqueon 72x18x29.5 tank, about 165g and I was concerned about the weight on an upper floor, so I found a nice house with a finished basement and put it down there.

you mentioned you are in a basement, can you put the tank down there? the earth should be underneath it, or at the very least, it is probably a slab concrete foundation. you should be able to put almost any size thank there, since weight of the tank with the 'world' underneath it is not a concern...


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## Lunafish (Aug 9, 2009)

12 Volt Man said:


> you should be able to put almost any size thank there, since weight of the tank with the 'world' underneath it is not a concern...


 :thumb: Now presenting the ultimate in stable and secure home aquarium stands. This revolutionary stand will securely support any size tank and is completely customizable Also it is entirely "Green" using only recycled materials. I give you the EARTH! A product of Mother Nature Industries Terra Firma Division. :thumb:

 Matt


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## non_compliance (Dec 4, 2008)

Sounds to me like Mr. Contractor is TRYING to find a reason to void your warranty.

I'm quite certain that your floor would hold that weight load. Right now my livingroom has a 65, 75, & 85 gallon tanks in it. The 75 and 65 are RIGHT next to each other, and the 65 is on a stand with 4 metal feet. THey are quite small too.

So I have 7' of tank (4' and 3') that is acutally on a smaller footprint because of the small feet on the 65, and more gallons (140).

Also note that my tanks are NOT ACROSS joists. (yes, I also run with scissors)

The 75 is in a corner, so I was not worried about that, because the corner is the strongest area, also with someone elses "lever" reference... I was confident there would be no problems.

As far as the 65, I had to set up an emergency temp tank. It is also against the wall, but out towards the middle of the room.

So in conclusion, I have 140 gallons over 7' width sittin on a single joist. I am possibly an idiot, and a bit nervous after running some numbers... lol.. but it's been that way for about 2 months.

A 125 perpendicular to the joists and spanning 3-4 joists will NOT HAVE ANY PROBLEMS WHAT SO EVER.

If you are nervous about it, pour a small footing in your basement, and put a beam under all of the joists, and put a post to the floor for added support.


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## bfg112 (Feb 13, 2009)

I wish I jumped in on this one earlier.

Moral of the story is: Order the tank. It will in no way void your warrantee.


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## CharlieTuna (May 20, 2006)

if this helps. and no laughing from the peanut gallery :roll: when i set up my 55gal i was worried because i was setting it up in the middle of the house and not on a support wall or outer wall so just for my peice of mind I placed the tank accross a number of beams as oppossed to along 1 beam and then as a 2nd measure I placed a 3ft piece of 2"x8" wood on the basement side of the beams with a floor jack underneath, also considered a cut to length 6"x6" but my father had some extra floor jacks so i barrowed one. I probly over did it for a 55gal but my house had a support wall removed years ago where a bed room was and the ceiling cracked there so I didn't want to mess around.


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## ambull (Jun 14, 2005)

I appreciate everyone who posted in my thread and pitched their suggestions. I thought I would provide an update. I went ahead with the tank purchase. I bought an Oceanic 156 gal and ran 3 2x8's, and 3 support beams in the basement directly under the middle of the tank (running in the same direction as the tank). This may have been overkill but I will sleep at night which is important if i am to perform at work which will allow for me to pay for said new house and tank :wink:

I will take and post some pictures of the tank and basement support when I am done setting everything up.


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## jpond (Jun 19, 2009)

ambull said:


> Okay, at the risk of sounding like a dumb ass.......
> 
> I was all set to buy a 215 gallon tank for my newly built house today. A tank that size weighs over 2000lbs. Builder came back and said my house could not take on that kind of weight and that I would have to hire someone to reinforce the floors for that size tank. He said that to stay in warranty, I could not exceed 10lbs per SF. Now, this is where my dumbassness kicks in. I calculate that to mean that a 2FT X 6FT sized tank could only be 120lbs. Also meaning, that if I laid in that spot I would be too heavy and void the warranty in my house.
> 
> ...


I sell building materials for a living. Some of the information above is acurate, and some is just plain bull. 
My suggestion to you is to get the plan for your house, take it your local lumber yard and ask them to have the engineering department calculate what you could use, such as an LVL (laminated veneer lumber). The LVL can be put under the floor joist with a couple of lolly coluns to support the ends, which would solve your problem. If you really want that size tank it would worth the maybe, extra $150 dollars for the material.


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## cjacob316 (Dec 4, 2008)

yeah telling a person that your floor only holds 40 lbs per square foot is like telling him he can't even stand on the floor so even though it may be 40 lbs per square foot times the area of the room for the total load in the room, the guy is a moron for putting it the way he did without explaining it, thankfully people like toby actually take the time to look stuff up and get the facts because people who should know this stuff apparently don't give a sh...


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## cjacob316 (Dec 4, 2008)

btw how much would it suck to place your 55 parallel to and right between two joists, i say 55 because i assume joists can't be more than 14 inches apart 55 is 13 inches wide, they may be closer and it could be impossible for a tank to not cross a joist


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## fox (Jun 11, 2009)

cjacob316 said:


> btw how much would it suck to place your 55 parallel to and right between two joists,


People could die, Be Sure.


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## bfg112 (Feb 13, 2009)

Floor joists are 16" on center, so yes a 55 could be placed parallel between joists. The weight of a full 55 is about 625 pounds. The preimeter of a 55 is 120 inches. That means, assuming the subflooring is 0.5 inches the stress on the floor will be:

625 lbs / (120 in * 0.5 in) = 10.4 psi

Average shear strength of southern yellow pine (the cheap stuff) is about 19 psi. That means the 55 can sit between joists and will not fall through the floor.

So many people worry about fish tanks falling through the floor, when really, unless the floor is rotted, it's just not gonna happen.


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## fox (Jun 11, 2009)

^^ Don't make me pull out my WFCM now.

Not sure on how your math works and how perimeter fits into the equation, you might need to recalculate your math steps.

A 55G tank will prolly be ok parallel to the jst's in most situations, 1nd or 2nd floor. The load has more to do with span and nominal dimension of the fl beam. 600 lbs on a 10' span will deflect less than the same weight on a 14' span and it is this deflection you need to be concerned with. If popping a seam is a concern anyways. You really do not need the tank to flex every time you feed the fishies.


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## bfg112 (Feb 13, 2009)

No, I do not need to recalculate my math steps. If you don't know how perimeter fits into the equation then you don't know what shear stress is.

And yes, given the same size joists you will have more deflection over 14' than you will at 10'. But, your not going to pop a seam in the tank due to floor displacement. And, I said nothing about displacement. All I said was the tank isn't going to fall through the floor.


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## fox (Jun 11, 2009)

Lighten up Francis.

Perimeter is arbitrary. 120 inches of perimeter is the same for a 55 x 5 as it is for a 50 x 10. one is 275 sq in and the other is 500 sq in. You might want to reconsider your approach, FWIW I am not sure you know how perimeter fits into the equation let alone design shear walls for stress.


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## bfg112 (Feb 13, 2009)

I think we can agree that the floor joists will hold the weight of the tank. I was responding the this post.



cjacob316 said:


> btw how much would it suck to place your 55 parallel to and right between two joists, i say 55 because i assume joists can't be more than 14 inches apart 55 is 13 inches wide, they may be closer and it could be impossible for a tank to not cross a joist


If a tank is placed between joists and we agree the joists will hold the weight, the only way for the tank to fall through the floor is to go through the plywood subfloor. With the tank sitting parallel and directly between joists the only way to fail the subfloor is in shear. The shear area is the perimeter of the tank (the base of the stand actually) multiplied by the thickness of the subfloor. I chose a subfloor thickness of 0.5 inches to be conservative. Shear stress is the weight of the tank divided by the shear area giving stress in pounds per square inch.



fox said:


> 120 inches of perimeter is the same for a 55 x 5 as it is for a 50 x 10. one is 275 sq in and the other is 500 sq in.


That is correct, and the shear stress on the floor will be the same for both. The bearing stress will be different, but shear depends on perimeter.


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## PfunMo (Jul 30, 2009)

We all pretty much have beat this subject to death on the calculations. It's pretty much agreed the builder is a jerk. How many times do tanks fall through floors even in the oldest house? What tells me the builder is a jerk is the way he reacted. He had a major chance to show his customer some real service. Like sending two guys and a few beams to make him feel good. Couple hundred dollars and he copuld have sent him on his way as a happy camper. Instead he pulls the jerk act and proves he can't be trusted. Is there any reason for him to whine that he just can't sell houses and goes belly up? Post up the guys name on every site and every day. Screw the greedy jerk.  
As for the warrenty, we all should know they are only as good as the company behind them. How much do you think this one is worth? If the windows fall out, is he going to fix them?


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