Will my aquarium fall through the floor?

[ReefDreamz]

You would be fine without any jacks or additional support if you weren’t in New Hampshire. In this instance the tank will absolutely fall through the floor especially since you are in that state.

If you don’t believe me ask an engineer but I’m sure they will back me up.

Modern wooden subfloors routinely fail in the State of NH.

Your sarcasm is not lost on me but the location was included because engineers often need to identify the type of wood used in construction of the home which varies in different parts of the country. All pine dimensional lumber is not created equal. It's mentioned in this article: http://www.african-cichlid.com/Structure.htm

 

[vintage detritus]

I had the same issue - same type of tank location, 6' 130G tank resting parallel to the 2 x 9 (net) joists. Jacks were out of the question. I used an online span deflection calculator and compared to tolerance charts. All good. Then, belt- and- suspenders, I had a structural engineer come out and take a look for a whopping $250 ( more than ten years ago, in the pricey SF Bay area) who ran the calcs, provided a report, and said I was fine. Like I said, belt and suspenders, so I sistered the affected and nearby joists with 2x8 (finished). Never had a problem.

Engineer said the danger was not the tank falling through the floor ( anybody ever hear of that actually happening in structurally sound house?) but instead the horizontal pull the joist deflection places on the load bearing walls. Like a string pulls on the bow, it can pull the walls inward, resulting in all kinds of problems.

I'd go with the SE or PE consult. You will sleep better.

 

[paintman]

I would go with a steel flitch plate bolted on the joist directly under the tank and 2 jack posts with a beam. Don't waste your money on an engineer he's only going to have you do the same thing. Except he will tell you to dig up you floor and put footings under the jack post. then hand you a 2K bill.

 

[ReefDreamz]

I would go with a steel flitch plate bolted on the joist directly under the tank and 2 jack posts with a beam. Don't waste your money on an engineer he's only going to have you do the same thing. Except he will tell you to dig up you floor and put footings under the jack post. then hand you a 2K bill.

Are you saying to bolt a flitch plate to the 2 joists under the tank? Those joists are 12 and a half feet long. That would be a massive piece of steel plus it would require removing the electrical and plumbing running through those joists, not something I could do myself. You don't think my idea of 2 4x6's running perpendicular to the joists each with a jack post below would be more than enough?

 

[jtf74]

Are you saying to bolt a flitch plate to the 2 joists under the tank? Those joists are 12 and a half feet long. That would be a massive piece of steel plus it would require removing the electrical and plumbing running through those joists, not something I could do myself. You don't think my idea of 2 4x6's running perpendicular to the joists each with a jack post below would be more than enough?

I think your plan is just fine. Use a jack plate like shown above .Concrete is normally like 3000 psi so I wouldn't worry about cracking.

 

[Supa]

I’m not an engineer but I am a carpenter and I would say it would support the weight. If it were my home and I was the one worried I would run another joist where the tank edges would sit. Use joist hangers etc your good to go. For that matter you could use a 4x6 or something beefy but don’t think it would be necessary

 

[Privateye]

Some good suggestions, but I just wanted to highlight that no structural engineer is going to give you a firm answer here. They wouldn't have liability protection of any kind. They may allude to suggestions but that's as close as you can expect. You've probably figured that but I just wanted to clarify in general.

 

[aws2266]

I'm curious what you ended up doing? I'm in the same situation with a 120g. My sister-in-law is working to become a contractor so I have her asking around about it. So far I've determined that my floor will hold 40lbs per square foot and the tank will weigh between 1200-1400lbs filled. We're looking at two options, building a frame, or use a steel plate and floor jack or a floor jack and either 4x4 or 4x6's. I'm hoping we can use the wood option cause that's gonna be cheaper. Priced out some steel plates and they are $250-$570.

 

[pdxmonkeyboy]

an aquarium will never "fall through the floor" . What happens is that the static weight will bow your floor joists.

Double up two 2x6 with glue and screws. Two installed around a foot inside the ends of the tank spanning the three joists supported by a single jack post. Done and done.

(I am not an engineer but I am "good with math and stuff" and have 800 gallon system above my crawl space.