Floor Reinforcement

hi all, please help this noob out with regards to how to proceed.

I bought my first house with a complete based that was build in 1996. I’m a huge aquarium hobbyist and would like to put a large aquarium on the main floor. the aquarium, with water and everything, will be roughly 2500lb but if you add people and whatnot, i will round it up to 3000lb for the sake of simplicity. the aquarium will sit in parallel with the joists and will be sitting on AT MOST 2 joists.

when i went to my basement, i discovered that the joists are engineered i-beams. but here’s the problem: whoever build the house made large cutouts in the i-beams. at least 2 large holes per i-beam. is this structurally safe? how do i go about and reinforce it so that the floor can support the aquarium? the aquarium is 6ft x 2ft. the ibeams are 11-7/8 inch with 19 inch spacing. the holes are just shy of 9 inches in diameter.

1st pic: showing size of the large cutout
2nd pic: showing at least 2 large cutouts per i-beam

Those engineered joists are completely compromised. You’ll need the services of a qualified framing contractor and quite possibly an engineer.

Read this. http://www.techsupport.weyerhaeuser.com/hc/en-us/articles/201758840-Where-can-I-put-holes-in-a-TJI-joist-

Strengthening the hole may not be your biggest problem. The weight of the aquarium may overload the joists. Can you supply the manufacturer of the joists and any markings found on the side? Also will need the span length and the distance from the support to the aquarium.

i can’t find the marking of the manufacturer anywhere that i looked. this is the only marking i was able to find.

one of joists is 16ft. the other joist that the aquarium could possibly sit on is longer. can’t see with all the duct work and foam insulation.

the distance from the load bearing wall to the first large hole is roughly 5ft. the center to center distance between the two large holes is roughly 32 inches.

the aquarium is 5ft long.


thanks. i have read this article before posted on other sites. however, it does not address how i can address the situation that i’m in.

i was recommended that i can put 2x8 on each side of the i-joist (for as long as i can) in order to somehow reinforce the i-joist due to the large holes. furthermore, i need to put a jack post per i-joist to hold up the weight of the aquarium. therefore in total there will be 4 2x’s (2 per i-joist) and 2 jack posts.

is this ok?

Considering the substantial weight you’ll be adding I would go directly to a structural engineer for the joist fix and additional reinforcing for the aquarium.

None of its rocket science but I think this beyond most contractors.


I did not see the grade of the joist, so assuming they used the cheapest joist that would span 16 feet, the two joists supporting the aquarium regardless of where it was placed would overload the existing joist.

I suggest you get a local structural engineer involved. Good Luck

I agree. :slight_smile:

That’s all you “can” do! You ain’t that smart enought to come up with anything else…HUH?..

Just messing with you Brother…
Then again…Maybe not! :twisted:

I think I have managed to repair, fix or build a few things a little bit more difficult than that problem, in the past Mr. Lewis. I’ll leave it up to you to come up with a solution. :wink:

how would you fix this?

That would only be possible to determine when on site and gather up all relevant information. My time to do that is equivalent to you calling a structural engineer to design it for you.

Probably should have had a Home Inspection to find those destroyed joists. If the floor isn’t sagging too much, I would be grateful and forget about the aquarium.

If you are committed to spending a significant amount of money for a significant remodel, hire a competent General Contractor with experience doing structural upgrades. No point in hiring an Engineer just to have him tell you that all those cut joists have to be replaced/doubled-up, with significant additional support going to where the tank will be. This will require redoing all the plumbing, wiring, and ductwork that currently runs through those members.

There are no cheap tips or tricks that will safely support a 3,000 lb aquarium.