How much weight can my floor take?

[kbnh]

So we've filled it up yesterday with tab water. Then we figured out that the floor is bouncy. Like really bouncy. It's just that few sqft between the staircase and the load bearing wall in front of the aquarium.

One firm step and the aquarium formed ripples on top. A lot of them lasting for as long as half a minute. It will also shake the floor when wobbling on the aquarium a bit. So when cleaning the glass for example, the water would start to splash and that would make the floor swing in resonance.

I measured from the rim to the floor and from the rim to the ceiling, but the floor didn't give at all. The leveling mat gave about 2mm.

We removed the water and it's still quite bouncy. There was a crack in the sheet rock under the middle floor joist's cross member. We feel like it has godden wider, but I forgot to measure it before and after.

Honestly, to see about 1500lbs shake like that is just terrifying. I nearly pooped my pants, that's for sure. I don't think we could ever sleep with that amount of bounce. My office is upstairs, so I walk past there every day, multiple times a day. Quite swiftly. Also once our son can walk, I don't want to be one of those parents that tell him "always be careful when walking past the aquarium because it shakes too much".

Gonna figure out how to go from here. It's really a bummer, but I don't think we could sleep at night like this.

If you really want it there ask a structural engineer on some options to increase support, provides solutions and peace of mind

 

[kbnh]

I would put a tank twice that size there and never think twice about it.

BTW - IRC says something like 40 psf for an entire room, minimum. They do not mention or cover smaller areas and the like. These are also minimums. Put both of your feet together and stand on the floor - this is about one square foot, or less. A 175lb human would collapse in a true 40 psf floor and they don't even budge. I don't know if IRC is the standard in the EU, but it does start with International. :) 300 gallons is my breaking point on floor joists that are running perpendicular with the tank - so like a 240g and 60g sump without even thinking twice about it.

Despite the name, the IRC is not actually an international code

 

[Asm481]

Is that finished space below the tank? The wobble is the killer here. You need to get support under it. Either an extra post or new structural floor joists. I had same dilemma with a 90 gallon tank only 2/3 full for a turtle.

 

[Mangimi]

Yeah it was all finished up space under there. We sold the large tank already and the small one which was standing there before is in my office now.

At the moment, we just don't have the time and nerve for construction in our home.

 

[BurgerFish]

That location for that tank is fine. You can also park your car there. It is supported by that 2X8 and the floor beams would be at least 2X6 but probably larger. I am not an expert on European construction but worked construction in New York for 50 years.

That's floor will support 72x32x20 or 96x30x22 tank?

 

[BeanAnimal]

One firm step and the aquarium formed ripples on top. A lot of them lasting for as long as half a minute. It will also shake the floor when wobbling on the aquarium a bit. So when cleaning the glass for example, the water would start to splash and that would make the floor swing in resonance.

Odd for such a short span to bounce that much, but who knows what they did under the sheet rock or how the joists are attached to the outside wall. The corner on the post is one thing, but given the joist direction and no other photos It is hard to tell how they framed the top of the stairs to the right of the tank. I assume just a double joist with stair box hanging from it and spanning to the post. So that doubler may be the source of the bounce and likely close to the drywall crack. It could be that the footprint and weight hit the right spot for it to resonate too. I doubt that there was any danger other than the rather bothersome bounce, but peace of mind is priceless, so I don't blame you for not wanting to leave it in that state.

 

[revhtree Verified Admin]

Did you decide on what to do?

 

[Dom]

That's floor will support 72x32x20 or 96x30x22 tank?

Shouldn't the 2x4s be the other way?

Installed this way, I would expect a bounce in the floor.

 

[dutch27]

Shouldn't the 2x4s be the other way?

Installed this way, I would expect a bounce in the floor.

Those are trusses, so they work differently than a 2x floor joist. Trusses carry the loads along the axis of the members, so its all compression and tension, no bending.

 

[Dom]

Those are trusses, so they work differently than a 2x floor joist. Trusses carry the loads along the axis of the members, so its all compression and tension, no bending.

Thank you.

 

[BryanM]

You either need an engineer or a new location.... Sorry to say.

And yes, that much movement would terrify me as well.

I do love that location, if I had the money I believe I'd be spending it in the improvements needed.

 

[Should I]

Yea ripples are normal on a wooden floor but 2-4 seconds of ripples not half a min. . .

 

[Üter]

the tank has been there for 2 years. did anyone look at the dates?