Worrying about the weight of my new tank

[robert_s]

Hi. I am getting a new tank (size: length 130cm/51", height 80cm/31", width 70/28")

I am not sure exactly how many gallons/liters but I guess it will be about 100gallons or even more. So really heavy. 1 liter=1kg

I leave on first floor flat with a wooden floor. It may sound silly to you but I am not sure if it will be safe to have such large tank standing on this floor. This floor is not made of concerete but wood as most of the old english houses. Do you think its OK?

 

[down&dirty]

If those measurements are right you are talking more about 190 gallon setup not 100. (51*31*28)/231=191.63 gallons. If you neglect the weight of rocks and sand and everything else and just consider the water you are already up to a 1600 pound setup. I would put the final weight with rocks and stand and everything to be on the safe side at around 2200 pounds. Remember SAFE SIDE. If you hunt around online you will find that most houses are built to handle a max of 204.8lbs/ft2. So you will need to distribute that weight over 10 ft2, but the key here is to distribute it across the entire 10 ft2. Which is just the space that you have under the tank. Personnally I would build a stand fill it and see what happens. I wouldn't have even crunched these numbers normally, but it is a slow work day. But, if you really want the setup, and chances are you do, I would try and get under the floor and check to see if the joist look up to it. It might be the case that with just a little reenforcement you will fell better about the weight.

 

[Anonymous]

By old english house, how old do you mean? If it has regular floor joists (around 16 inches apart) make sure that you place the tank perpendicular to the direction the joists run. That way it will be supported by many, rather than one or two joists.

Do you have a basement? If so it's easy to insert some kind of support columns underneath for insurance.

 

[robert_s]

thx down&dirty

I would try and get under the floor and check to see if the joist look up to it.

Yes I'll have to get under the floor and see the joists condition.

make sure that you place the tank perpendicular to the direction the joists run

Very good point DanConnor.

Thank you for help all! I'll get this tnak no matter what!

 

[Fl_Seagull]

I don't know about old English houses; but, I have been under many old American houses and would question the 204.b lbs/ft2. Most 20 yrs or so American houses would meet this. However, 50 - 70 yrs old American house would not. One I worked on was close to 125 lbs/ft2 and each step felt like the the whole floor was a bouncing.

I would recommend adding some support.... or at least make a measurement before water and various point as you add water. If you see the joists sag more than an inch(25 cm) I would re-enforce. JMO

 

[Fl_Seagull]

How about 25 mm . At 25 cm you have broke a joist.

 

[ChrisRD]

If you hunt around online you will find that most houses are built to handle a max of 204.8lbs/ft2.

Do you have a link? I'm curious as to where this number came from...

 

[ChrisRD]

FWIW, most modern homes in America are designed for a 40 PSF first floor live load (live load = furniture, people, appliances, fish tanks, etc.).

Unfortunately, thinking of the floor loading exerted by the tank in terms of pounds per square foot (PSF) isn't very helpful in determining whether or not you're OK. There's no easy answer. A real answer requires a lot more information and a much more complicated analysis...

For those who are interested, check out an excellent explanation here

 

[down&dirty]

I did some more hunting for floor load requirements, and I couldn't find the link that had the numbers I used earlier. The nuber they quoted was 1000kg per square meter. All the other numbers I came up with were around the 40 psf range depending on the city. Some are working to get this increased.

 

[Fl_Seagull]

Thanks to the moderator for the link. It is a good article of the issues and problems with answering the question of "Will my floor support my tank?"

I won't attempt to defend my numbers since my I have already proven myself to be a fool.

But, I will attempt to shove the rest of my leg into my mouth .
1) The main point I would like to make is that old houses were built to different standards and the orginal structure may be stronger or, more likely, weaker than modern houses.
2) Most homes I have been in of the 50-70 yr range had hidden damage to the joists from water or insects which reduced the overall load carrying ability of some parts of the floors.

My one fault of the article is that it leaves me thinking that I can only have a 55 gal tank before calling in a structual engineer and contractor. Since the author is a structual engineer, I suspect he is playing it very safe.

Obviously, if you live in a warehouse converted to condos you may be able to have a large tank without a worry while if you live in an apartment which bans water beds you may need to just get a bird.

I would recommend building support under the joists to support the whole weight of the tank. If I was doing the work, I would double the joists in the local area. Then place blocking between the joists. Support this with a built up beam, of 3 2 x 8 (3ea 50 x 200 cm?) nailed together, centered under the tank. Support this beam with a steel column. If you have a concrete floor on sand this is typically good for 2000 lb/ft2 while clay may be as high as 4000 lb/ft2. I would recommend placing a steel plate to spead the load of the column over atleast a 1 ft2. Of course, you may not have the room for all of this. but it will give you an idea of what is involved. $300 -$400 worth of materials is a small price compared to the cost of a damage from an undersupported tank. JMO which has been proven wrong before :lol: .

 

[Anonymous]

FWIW, most modern homes in America are designed for a 40 PSF first floor live load (live load = furniture, people, appliances, fish tanks, etc.).

I never really understood these kinds of numbers. How is it that I can jump up and down on one foot, effectively putting 100 PSF (~215lb / ~2 sq.ft) or more (considering I'm jumping) onto a floor between joists and not go through the floor?

 

[Anonymous]

John, read the page(s) on link above more carefully. You're putting a short-term puncture-type pressure on the framing, not a sustained load. - In the link above an analogy is drawn using the cutting of a tree. (You know, notch it, back cut it some, let time/pressure take it's course.. - You could back cut it, give the trunk above the cut a solid smack and it'll just sit there, but if you don't touch it, give it a little time...... TIMMMMBER!)

Anyway....

Something else to consider for those thinking of putting a nice big tank in the basement...

New houses in some areas are now being built with radon venting. - What this means is that your basement floor doesn't sit directly on the ground.

There is a layer of pea-gravel put down and then plastic sheathing on top of that which is gathered around a vent that should run straight up through the roof. Your floor is poured over this sheathing, leaving lots of little air pockets between it and the ground.

I would guess theres some risk in having a big tank sitting on top of something like this as well, though probably not as likely to be as obviously catastrophic as an upper floor failing.

But it could become an issue come sale time if there are large cracks in the floor where the house is supposed to have radon venting.

 

[Anonymous]

John, read the page(s) on link above more carefully. You're putting a short-term puncture-type pressure on the framing, not a sustained load. - In the link above an analogy is drawn using the cutting of a tree. (You know, notch it, back cut it some, let time/pressure take it's course.. - You could back cut it, give the trunk above the cut a solid smack and it'll just sit there, but if you don't touch it, give it a little time...... TIMMMMBER!)

::thumbsup:: I just never understood how that worked.

 

[ChrisRD]

John,

The PSF thing (ie. your jumping on one foot example) is a common misconception. The article I linked above gives a pretty thorough explanation - there's really not a short answer, unfortunately.

Basically, the floor system is designed to handle an average load of 40 PSF over the entire floor. In other words, the floor structure of a 15' X 15' room (225 SF) should readily handle a uniform load of 9000 pounds.

Now, if you want to concentrate more of that load in certain parts of the room (ie. a large fish tank) it gets more complicated. You have to take into consideration where the tank is in relation to the supporting structural elements of the floor, how it is oriented in relation to those elements, what condition those elements/connections are in, etc.

Also, keep in mind, when a structural engineer talks about a structural failure, we're not necessarily talking about something falling down or crashing through the floor. That's a sudden, catastrophic failure and would take load levels WAY beyond design loads.

There's acceptable amounts of deflection for your floor construction. If the load you're putting on it exceeds that deflection the system is beyond capacity. In the case of a fish tank this could have indirect catastrophic effects, for example the tank could also deflect, crack, and flood your house. The excess deflection might only result in a sagging floor, damaged floor/wall coverings, etc.