Floor support question

djray77 · Sep 24, 2021

So I'm thinking about setting up a waterbox 100.3 in the office and wanted to get some thoughts on if the floor would support the weight. I googled 100 gal saltwater and it says its 850lbs but then you have sand, rock, etc so maybe about 1000lbs to be safe. Take a look at the picture and let me know if I should be OK or not. Thanks for any help.

redfishbluefish · Sep 24, 2021

Not sure if anyone can definitively give you an answer without a full inspection of all structure. That said, a 100 gallons on relatively new construction with a steel beam directly below on the wall edge.....I'd do it. I've done it with a 90 gallon DT/50 gallon sump without issue (although I did sister the existing beams), and my tank was parallel to the joists..

Now one thing that potentially is bothering me is whether or not there are squash blocks above that steel beam. It's too dark to see and tell. Google it if you're not sure what I'm talking about. Squash blocks keep wood I-beams from "squashing" from point loads. The steel beam creates a point load. If they're not there, please simply install them.

djray77 · Sep 24, 2021

There aren't any squash blocks that I can see the steel beam goes right onto the wood. How would I install blocks?

My only concern would be the back of the tank will be right under them posts and beam but the tank will be sticking out 2ft so the front of the tank will not. Is that an issue or not I guess is the question?

Onewolf · Sep 24, 2021

Keep in mind that the 850 lbs is just 100 gal of saltwater. Does not include the tank/stand/sump/equipment/sand/rock/etc. Unfortunately Waterbox does not include weights in their 'Tech Specs'.

That being said the stand is about 36"x24" = 864 sq"

1500 lbs (high estimate) / 864 = 1.73 lb/sq in. Which is not a lot.

I would not worry about that loading, but I'm not a structural engineer.

I don't suppose you have the engineering blueprints for your house?

djray77 · Sep 24, 2021

No, I don't have blueprints, unfortunately. I guess it's good I have them steel posts. I think it should be fine also, but as you said I'm not a structural engineer either. I was hoping maybe there might be some on here lol.

Onewolf · Sep 24, 2021

For your entertainment: https://www.thehulltruth.com/dockside-chat/1187184-ok-all-you-tht-structural-engineers.html

djray77 · Sep 24, 2021

So it seems like it would be fine.

flagg37 · Sep 24, 2021

I wouldn’t even hesitate with your situation. Full speed ahead.

djray77 · Sep 25, 2021

I'm wondering now if a 4x2 tank would be ok or maybe pushing it?

redfishbluefish · Sep 25, 2021

djray77 said:
There aren't any squash blocks that I can see the steel beam goes right onto the wood. How would I install blocks?

My only concern would be the back of the tank will be right under them posts and beam but the tank will be sticking out 2ft so the front of the tank will not. Is that an issue or not I guess is the question?

Squash blocks are very easy to add after the fact. Now I haven't been involved in commercial construction since the mid 90's, but I'd swear that the residential code required them on all point loads of wood I-beams. Anyway, HERE's the first link that popped up on my search explaining squash blocks. I usually used scrap wood, but a couple 2x4's should be good enough for your application.

djray77 · Sep 26, 2021

So if I add those blocks what would be the biggest tank I could go with you think?

Onewolf · Sep 26, 2021

djray77 said:
So if I add those blocks what would be the biggest tank I could go with you think?

I the grand scheme of $$$$ involved with a large tank, I would hire a structural engineer to give you an accurate assessment of the current load bearing capability and probably some inexpensive modifications that could increase the safe load.