Would i have a strong enough floor

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Invest777
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Would i have a strong enough floor

Post by Invest777 » Sat Jan 11, 2020 1:55 am

Ok I'm planning on building an approx 700 gallon plywood aquarium. One of the issues I'm going to be dealing with is : wondering if the floor will hold the approx 7000lbs of water and tank.

So the tank is going to be up against the wall which is at the edge of the house, also is right above the cinder block foundation. My plan is to sister serveral 2x12s to the existing floor joist in the basement to help support the weight then also build an support beam the span of the tank in the basement supporting the 2x12's and taking some of the weight off the cinder block foundation

Kinda sound like a solid plan to me. Do you think this plan is adequate or even necessary?

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Shannon
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Re: Would i have a strong enough floor

Post by Shannon » Sat Jan 11, 2020 9:09 am

Sounds like you have thought everything through except "plywood" aquarium? That sounds like a disaster waiting to happen.
Actually I do have other concerns. You say 700 gallon tank and 7000 lbs which would be correct for the water only. I would think you will have rocks ,coral,plants,fish,equipment and the tank itself as well? You need to factor all of that in ,I would guess you are likely more like 9000 pound min. I would likely add a second beam under the end of the joists at the wall as well. Since this is a lot of weight and you need more than just joist hangers and nails holding this thing up. I would be more keen on placing this in the basement on a solid concrete floor. Are you sure this is really a good idea? 700 gallons of water in your home is kinda scary to me.
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A. Spruce
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Re: Would i have a strong enough floor

Post by A. Spruce » Sat Jan 11, 2020 9:27 am

I would agree with Shannon, more than 7k pounds in total and more support needed! This is a lot of weight, you don't want any chance of structural issues. I would suggest supporting the joists every 3 or 4 feet along the length of the tank with beams and posts that go to the floor. Second, what is the thickness of the concrete floor, anything less than 4" isn't going to have the strength to support that weight, you may need to thicken the slab in this area as well.
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Shannon
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Re: Would i have a strong enough floor

Post by Shannon » Sat Jan 11, 2020 9:30 am

Good point about the concrete floor below the posts Spruce. All of those point loads may crack the concrete .

You may actually have to get an engineer involved here , we can give general advice but this is kinda out of the ordinary for sure.
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Invest777
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Re: Would i have a strong enough floor

Post by Invest777 » Sat Jan 11, 2020 10:22 am

Ok. Thanks guys. First to answer shannon. Few weeks ago plywood aquariums were unknown to me as well. Until I heard and saw people building them on YouTube upwards to 1500 gallons! Granted not on a floor joist. But it's basically using strong birch 7 ply plywood/ also additional framing and waterproofing the plywood with waterproofing epoxy. It's basically a cheaper alternative if a person doesn't want to spend $3000+ on a aquarium that's 300+ gallons. Plus if done correctly the aquarium really holds up.

I did have my doubts about putting that much weight in a short span of an area. I might just go with 300 or 400 gallons instead with the same setup.

Also I would assume that the basement concrete is 4+ inch thick. But a fish tank in the basement is a no Go, sense I wanted it for an attraction. 250 gallon tanks are common in living rooms, i would think adding 150 gallons more wouldnt be a huge issue with the extra loading bearing wood added.

But the plan was to install around (8) 2x12 on the seal plate of the foundation that extends to the center beam of the basement. Than add an additional beam as well just in case you guys needed more clarity.

But I'll do some more studying and probably get an engineer opinion as well

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Shannon
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Re: Would i have a strong enough floor

Post by Shannon » Sat Jan 11, 2020 4:35 pm

If you go this route I would use a wider metal plate under each post to spread the weight out over more floor area. Maybe a 3/8" plate that is 12"x12" or so?
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Invest777
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Re: Would i have a strong enough floor

Post by Invest777 » Sun Jan 12, 2020 6:09 pm

That's a good idea Shannon, will do.