Additional floor support for 180 tank


New member

How do you know or what calculations did you use to figure out how much weight a floor joist can take? I noticed in your photos that you reinforced two floor joists in your basement. I guess it's because the tank appears to run parallel to the floor joist.
Worst case, if you didn't reinforce the two floor joists, how long would it take to crash through the floor? Is there anyone who's experience this unfortunate occurance in the past?

wsrich :eek1:
I have a friend who is a Mechanical Engineer. She calculated the amount of support and bracing I would need.


Did the mechanical engineer tell you approximately how much weight one floor joist can take at one time? :fish1:
It depends on how much load, and the way that your floor will support it. In general, I would not worry too much about a catastrophic failure, unless your home is not built to code.

The necessary information needed to calculate this would be the geometry of the tank, and how many joists it spans; the size of the floor joists (LxW); the span between the joists and the support beam for those; and the location of the center of the tank relative to the joist end supports. With that information a beam stress calculation can be done. If you have good flooring, I would not worry too much about it, typical floor joisting is 2x6 with 12-16 inch spacing. You will hit at least one joist, and if you are close to a wall you can count the wall support as a second joist. A 180g tank should easily be supported by 2 2x6 members.

(although I will not accept ANY liability for above statements) :D

wsrich said:
Did the mechanical engineer tell you approximately how much weight one floor joist can take at one time? :fish1:

No... I just gave her all of the information and she told me the best way to reinforce the floor. :)

Rather than start a new thread I figured I'd piggyback on this one.

I just installed last night a 180 in the typical "worst case" scenario of parallel with the joists in the middle of a 12' beam span. I guess I have to say I was surprised at the effect this had on the floor. It is quite bouncy in front of the tank, with normal walking causing water ripples and a slight "hop" causing the tank to rock slightly, but perceptibly. While I seriously doubt this would cause a floor collapse (my West Virginian civil engineer friend would still claim that it was 'overbuilt' - but you should see his house), it's annoying and could cause undue stress on the tank in the long run.

I will be off to Lowe's for two jack stands and some 2x10's this evening. I perceive a new wall appearing in my basement tonight!

How did your experience go?
in the middle of a 12' beam span.

Yeah... That is definitely 'worst case'... The span is a direct multiplier to the bending stress on a beam.

Yes... The "calculations" regarding beam deflection/beam stress don't take into account dynamic response (vibration inputs). Reinforce the floor; otherwise 'walk softly', and no dance parties! :p

I will be installing a 150 soon. I was 'peaking' under the house over the weekend through an exterior vent (just have a crawlspace) to determine if I can snake plumbing lines through to a sump in the garage. I noticed right away that there is a 4x6 beam running in parallel to the exterior wall (in about 1'). This makes me feel better about the support issue in my situation.

Hmmm... I wonder what kinds of stresses are imposed on your floor during an earthquake (being that I live in earthquake central)! :eek2: