Floor reinforcing for Aquarium

Hello everyone,

My first post here on this site!

I need some assistance on how to properly reinforce my floor for plans of a 210 gallon reef aquarium. Currently there is a 79 gallon in place.


Tank I plan to upgrade to is a 210G from the same company. Foot print will be 63" x 31.5", aquarium is about 500lbs plus roughly 210 gallons of water and stand is maybe 100-200lbs.

Interestingly my current home only has supports running across the center of the house perpendicular of the joists. Unlike homes I been under in the past there were supports or jacks every few feet of the entire floorplan. I did notice a different joist design. Older designs I seen were just straight solid joists where mine looks like a truss type joist design.

Here is a quick drawing of the floorplan.

Access hatch




Truss type joist

Joists are 24" apart.


The back wall where the tank is sits in front of is right on top of the cement support underneath. I'm guessing a main support for the house and 2nd floor.




Other side of the house

It looks like you have serious water issues under your house. I can see a water line 6"-8" deep on concrete! You will want to make sure this is an old problem. On the fish tank thing, looks like you'll play hell trying to find something hard enough to pour concrete on. But one great idea I can think of is get two sheets of 3/4" plywood and rip them full length(8') long by height of floor trusses minus 1/4", this will make it easier to get them in. Now take them, should be about ten of them, and bring them under house with some decent nails. Start just past one end of tank and slide boards above foundation wall about to where the upward web attaches behind foundation wall, this should leave at least 4' or so past the front of new tank. Hold them flush with bottom of truss and nail to truss every 8" across top and bottom and on diaganals. Do this on both sides of them, should be five trusses, to get you beyond both sides of the tank. Now that thats done, scrape the earth away from bottom of foundation along this wall to expose lip of footing. Now you can cut 2x4's at angle that rest on footing ledge at ground and go to bottom side of truss about 2' off wall. You should place building or tar paper under these on concrete and use 3" screws, 2 in each board, to fasten to truss at each truss you have plated. Now you are ready to fill tank. And don't forget to check into that water marking. Good luck!......

No offence ...but you must be an engineer Triple D.
You need an engineer plain and simple, the advice you got will lead to failure of the truss. Those are top loaded trusses and the concrete wall between them is doing nothing as far as support goes. The truss buy-passes the wall in one picture and is supported somewhere else.
It's your decision, but I know any inspector coming through "will" need to see documentation it was done by a licenced engineer, with the paperwork.
Also update that crawlspace by installing some plastic on the dirt....your house will last longer.
Good luck with the fish.

Sorry it's been a while. I didn't get the notifications that there were replies. But here's what I ended up doing after talking to several contractors and framers.

We used 3/4" plywood to sandwich the sides of the 4 joist. 11" high and 4' long with 3 1/2" screws.




Once the boards were in place we also used 4 screw type jacks to reduce floor bounce on a 2x6 and 12" pavers dug 4" down.


There's almost no floor bounce now with me jumping in front of the tank half full. before doing it I could make ripples from jumping. I'm glad I did this.

floor jacks love to kick out especially on wet dirt. looks like the are not very level. it would be a good idea to make sure they are level before filling the tank up.

Sorry I did not mention. The jacks were in place for the pic at the time of that pic. They are actually sitting on 12x12 stepping blocks that was recommended to be dug down, set, jacked, then burried so it does not puddle if it ever flooded.

I'm not sure why there's a water line on the cement wall. Possibly from the building stages of the home? The foundation is quite elevated from the street level. The perimeter of the home is all concrete and drained to the street.