Will my floor hold it? Structural engineer recommendations

[JollyGreen]

Hey all,

So long story short we had a 210g waterbox peninsula, and while moving it into the new place it broke, ran the corner of the tank into the door nob. So after looking for a replacement come to find out they don't make that tank anymore so there was no way to find a replacement tank to go on the stand. So of course I took this as a sign from the heavens that the tank was too small, and promptly ordered a 300 gallon tank stand canopy from glass cages 96L x 30W x 24H.

It got here today and boy is it BIG. super excited, but I'm having some second thoughts. I mean we're talking a minimum of 2400lbs from just the water, not to mention the tank is heavy The tank is on the 1st floor above the basement. It's in a corner 12" away from the exterior wall and the wall behind it is a concrete block wall. It's parallel on the joists and they look to be 16" apart. So I am thinking I should support the floor with at least 4 column jacks and some wood to spread the load. I have zero experience with this, I'm new to the area and where I'm from (south florida) everything is built out of concrete so I've never had to deal with wood floors like this.

So any suggestions or thoughts would be appreciated. Also I'm looking for a recommendation on a structural engineer if you know of one.

thanks in advance.

Jorge

no swearing...

 

[BiGGiePauls33]

You can take a look here at Nick's build for an idea:

Nick's 345G Build

Howdy, Welcome to another new chapter of Nick Liu's build thread. lol. Hopefully, this one will be up longer than the 3 years on the last Miracle build. The last tank build can be found here. And the prior tank is somewhere in that thread. I think it's toward the end...

bostonreefers.org

 

[coralfishreef]

... So of course I took this as a sign from the heavens that the tank was too small, and promptly ordered a 300 gallon tank stand canopy from glass cages 96L x 30W x 24H.

Looking forward to your build.

 

[this is me]

Here's the blunt reality and my blunt response.
You've expressed concerned about what you're doing and therefore aware of the potential catastrophe. That tank will end up over 3600lbs when it's all set and done. Sitting on two parallel joists, 2x12 at best. Even if we pose here as structural engineers(and I'm not) and say it's okay, would you be able to sleep at night? You shouldn't...
Have you looked into getting a structural engineer to come inspect the floor? Just to get them into your door and write some recommendations alone will likely cost more than the work itself.

Wood is stronger than most people give it credit for. However, wood flexes! If that floor don't come straight down after the tank is filled, it will bounce when someone walk or especially when a kid runs in the same room. Wood can hold up a lot of weight only if they're used right with enough pieces to support each other. A tank that size sitting on parallel joists would not allow me to sleep at night.
Also, having the tank near a wall but it's sitting on parallel joists is no better than the tank sitting in the middle of the room.

 

[gobyvin]

Nick is right, I would be very nervous about placing that parallel to the joists and without additional columns below. It could be done parallel, but the joists should be sistered on both sides, add perpendicular bracing in between each one and the neighbors for as far as possible, and install columns (4 minimum and maybe 6 to be safe). I am no engineer, but I think this would be enough. Load bearing range for conventional lumber is easily referenced on the internet. I would check what your house is made of at a minimum and go from there. I highly recommend changing tank orientation to perpendicular to joists in house, and then add additional supports too. Parallel is hard to prevent crushing of single joists under the immense weight over time, creating a front to back lean potentially and unevenness of the tank.

 

[PSU4ME]

Proactively brace it, no doubt. As Nick said, you’re already pushing boundaries so just plan to do it. It’s actually quite simple to do. The heavens also agree......

 

[kgstei]

Yes you definitely need to brace underneath your tank. Wood 4 x 4 posts would do a great job and they're much cheaper than screw jacks.

 

[nilaydeshmukh]

I am not a structural designer but an architect by profession. I have worked on several substantial size building over my 20 years career. Normally, houses are designed to receive uniform live load of 40 pounds per square foot (40 psf). From the footprint of your tank, it will be adding approx. 480 psf of live load that too parallel to the joists. Most buildings can handle more loading than what they are designed for (with factor of safety included). However, this is 12 times more loading than what is anticipated. In my opinion, this much of additional loading (especially parallels to joists) is not advisable. At the advise of my colleague who is structural engineer, I had doubled up joists and had added additional studs to transfer the load to the basement for my 120 gallon tank. A much as I would like to have a bigger thank, I couldn't do it. You also need to consider seismic implications. Just last month (on 11/8) southern MA/RI experienced an 3.6 magnitude earthquake. Thankfully, that was a minor event. Structural integrity of the entire house could get compromised due to uneven load conditions when dynamic forces such as hurricanes or earthquakes are applied. Though wood is a good material to carry bending loads, it could suffer shear failure with so much additional loading in a focused area. Ideally, if you are able to do it, the entire footprint for the tank should be independently supported and separated from the rest of the house (structurally) with a seismic joint so that both the structures stand on their own and could move independent of each other. I would urge you to consider overall safety of your house/family and suggest hiring a structural engineer before you fill the tank.

 

[MDFiend]

Is the basement a living space? If not, what I would do is build a solid wooden box in the joist space with lumber that matches the joist size you have. Then get/or rent some screw jacks and lift the local joists about a 1/4". Then buy a few pallets of hollow core concrete blocks. Then get the sand, portland cement and lime, and build a masonry wall right up to the timber box built in the joist space. Then lower the 1/4" onto it. That would be plenty of support with a distributed load force straight to your foundation floor. I replaced my whole foundation with masonry wall myself by hand. Do some research and you can do it. I believe in you.

 

[wdebenedettojr]

Not anywhere near a structural engineer but I use to work at a large fish store and was a part of a lot of large aquarium purchases/installs 200, 300, 400 gallon tanks. I can tell you once someone got to 150 gallons we would always strongly suggest an engineer come out and look at the structure. I have seen 250 gallon tanks on 3rd floors before and there is no way I would ever do that nor would I be able to sleep at night. I would strongly recommend you at minimum consult with an engineer or like nick said, the cost to do so might cost as much to just reinforce your floor. Good luck

 

[coralfishreef]

Check with your home insurance company too.

 

[Stanley Wong]

What is the span (between support beam) of the parallel joist ? 16’ ? Double the joists and put the 4x4 column support from the ground.

 

[bvs12]

The age of your home plays a huge roll on what you will have to do to make this safe. If you have an older house the slab in the basement might be thin and just adding 4x4 from the joist down might not be enough. Because they could punch a hole in the thin slab. I am a carpenter and have seen slabs do this. The size of the floor joist also are a big concern. Could build some walls under the tanks and maybe incorporate them into a room in the basement. Walls with plywood would be the best way to transfer load to the cement slab. Plywood on them will keep stiffer and help transfer load down.

 

[kgstei]

The age of your home plays a huge roll on what you will have to do to make this safe. If you have an older house the slab in the basement might be thin and just adding 4x4 from the joist down might not be enough. Because they could punch a hole in the thin slab. I am a carpenter and have seen slabs do this. The size of the floor joist also are a big concern. Could build some walls under the tanks and maybe incorporate them into a room in the basement. Walls with plywood would be the best way to transfer load to the cement slab. Plywood on them will keep stiffer and help transfer load down.

Best answer yet! It's actually what I'm doing in my house. I'm using 2 by 6 plates and four by four supports. I drilled the slab and it's 4 in but I also found out that the floor joists had an unsupported load from the second floor. And like Joe Rice 's comments below I'm making a sturdy Closet in that area..

 

[Joe Rice]

If you have an older house the slab in the basement might be thin and just adding 4x4 from the joist down might not be enough. Because they could punch a hole in the thin slab.

When I first got my 150g tank I needed to add a jack post in the basement and faced just this problem. I wound up buying a 3/8" thick 7" diameter metal disk to place under the post to help distribute the load a bit. Eventually I finished the basement and replaced the post with a ridiculously overbuilt closet

 

[Knight]

Is the basement a living space? If not, what I would do is build a solid wooden box in the joist space with lumber that matches the joist size you have. Then get/or rent some screw jacks and lift the local joists about a 1/4". Then buy a few pallets of hollow core concrete blocks. Then get the sand, portland cement and lime, and build a masonry wall right up to the timber box built in the joist space. Then lower the 1/4" onto it. That would be plenty of support with a distributed load force straight to your foundation floor. I replaced my whole foundation with masonry wall myself by hand. Do some research and you can do it. I believe in you.

By yourself??? That is not exactly how I remember it. :O But yes, totally doable.

 

[this is me]

OP probably thinking "WTF have I done" at this point. Lol.
It could be a little overwhelming at first but building the support is not difficult or costly. But it something you must do.

 

[DJTank]

Even with the reccomendations of building a closet of sorts, which you will have to do, you do really need to ensure your slab can hold it. Beams without footings will go through the majority of slabs with that weight, then you tank falls and now you have a major structure issue. If you do wood walls you will need at minimum 2x6 with plywood walls at least 1/2, and suggest larger studs and toung and groove 3/4... actually suggest cement with new footings (thats what I would do). You likely will need to cut your floor and build footings. It seems like a lot and I get it but you don't want to find out in a few years you caused massive damage to your house. The reference to 40 pounds per square foot is all you should consider (which is about a 55 gallon tank - wide not tall). If any contractor tells you less, don't use them. It is not worth saving a few hundred and risking catastrophic damage to your house. I strongly suggest having a structural engineer do plans, a couple hundred for insurance and piece of mind is well worth it. I would then still slightly over build to those plans incase you add extra rock or a chair next to it or something, give yourself some padding. Heck, you can turn the room below into one heck of safe by putting some steel reinforcing into the walls and a safe door.... or of a walk in refrigerator & keg room with a cooling unit and insulation... or a wine closet and make the wife happy .

 

[CrypticLifeStyle]

nilaydeshmukh Nailed it! I'd say start planning your basement fish room bud. Man cave it up!