Found this an interesting read

[Dearth]

Not sure if it has been posted before but found this an interesting read about placing larger aquariums on joists from a structural engineers PoV

http://badmanstropicalfish.com/articles/article28.html

[Evilweevil]

It was interesting , so I have to ask the question has anyone actually have an aquarium collapse a floor ? Or do damage that way?

[Evilweevil]

So after some searching all I could find was people asking if there tank would fall thru the floor not actual happenings off this , but i do find lots of stories of the seems splitting and the tanks rupturing ,so it makes me wonder if this could be what happens the tank gives way before the floor ever does .
Fill up a90 gallon with the back legs on a more solid joist the front feels solid but over time it flexes and gives maybe 1/8 to a1/4 inch the tank takes the stress and leads to failure in the tank ? I would think a tank could handle an eight but a 1/4 or more would be a lot

Might be a good myth busters episode

[Dearth]

I have found several instances of tanks falling through the plywood substrate but have only found one case of actual joist failure that was attributed to termite damage. A 110 gallon tank fell from 2nd floor through first floor to basement in a house in Georgia in the mid '90's and root cause was attributed to termite damage.

[Myka]

Thanks for posting! I'm a carpenter so I know those basics, but it is a GREAT article to link people to that is in layman's terms that anyone can understand.

Originally Posted by Evilweevil

It was interesting , so I have to ask the question has anyone actually have an aquarium collapse a floor ? Or do damage that way?

I've twice seen people use support posts in a basement to support a main floor aquarium in which the posts cracked the basement floor. I've heard "millions" of horror stories, but seen very few pictures of real incidences. The thing is, most people don't have aquariums that are big enough to do significant damage.

[sphelps]

The idea behind floor support and aquariums, or anything for that matter that your floor has to support, relates to displacement not gross collapse. The floor is designed to hold a certain amount of weight while not deforming enough to cause issues like floor warping or cracking tiles. The actual amount required to cause the floor to completely collapse would be significantly higher. It's actually so much higher it makes it pretty much impossible to do, even with very large aquariums. Even if you did manage to produce enough load to cause collapse the warning signs would be obvious enough to make you stop before causing joists to shear or buckle. In other words it would take a very "special" person to actually put a tank through the floor.

This of course doesn't mean you can install as big of a tank as you want without worrying about it. You simply just need to realize that your goal is to prevent displacement and not gross collapse. As Myka mentioned as well it's not as simple as just sticking support posts under the tank either. Posts need to be installed over piles, point loading a 2-3" slab will really do nothing except cause it to crack if it actually takes any load.

[Myka]

Originally Posted by sphelps

In other words it would take a very "special" person to actually put a tank through the floor.

Thanks for the chuckle.