Is reinforcement to floor needed for a 135-150 Gal Tank?

[ajm1961]

Someone told my wife that a tank of 120+ gallon is best placed in the basement because of the risk of the floor breaking(?), as the weight is too much.
Can someone tell me whether this is true? I live in a standard Minto built home, built in 1988, and was planning to put the tank on my main floor.
Any advice would be appreciated.

[jimskoi]

Is it going on an outside wall?
I wouldnt put it in the center of a room myself.If its on a wall that has a supporting wall under it.It would be fine.

[Quatro]

If given a choice I prefer to have large tanks in the basement on the foundation.  It is about 10 pounds per gallon of water so your 135gal would be around 1350lbs  

What a lot of people here have said is to make sure that the tank is running perpendicular to the floor joists.  Typically this means put in against the longest wall (external wall is best).  A 6 foot tank would then be resting on 4 or 5 floor joists which distributes the weight.

As jimskoi mentioned, a supporting wall underneath is a good ideal.

[jenn_zep]

i have a 90g tank with over 200lbs of rock on the secound floor of my houseagainst an interior wall with no supporting wall beneath. and  my place was built in the 50s, and i have no problems.

[garnpet]

I have my 150G on the floor with the joists running the wrong way.  We had the floor reinforced so that there are now 4 wooden posts underneath the tank in the basement "holding things up" so to speak.

[QueensU]

Just find 8 people who weigh 200lbs to stand in the spot where the tank will go!

[QueensU]

Haha, I was j/k. Hope It works out for you. If you were worried about it, you could always buy a jack post from Home Depot or somewhere. If you're in the same minto townhouses I was, there is already one jack post in the basement. Just put another one under where the tank will go and tighten it up. The standard red jack posts are rated for more than enough to support a fish tank. You would still have to make sure that the area around the post wasn't sagging at all.

[ajm1961]

Thanks to everyone for your advice.
I will definitely try to position the tank near an exterior or weight-bearing wall, perpendicular to the floor joists, and perhaps look into a few steel jack posts to help out the structure underneath as well.
This is a great forum!

[Canoe]

I've been told not to have a tank near an exterior wall to ensure temperature stability. Anyone? Anyway...

I'd take a different point of view. Where is the location you want your tank? To me, I'd want it where I can see it and enjoy it the most. Then I'd make that spot suitable, be it a separate electrical line on a GFI breaker, etc.. Is your basement finished in the area under where you prefer the tank?

Depending on the ease of access to the floor joists, ducts, plumbing & wiring, there are a number of ways of making the floor stronger and stiffer, including:

• doubling up floor joists (glued & screwed), locally or full span,
• solid cross-bracing,
• a supporting wall,
• jack post(s), and
• combinations of the above.

Let's call a 1,350 lbs. aquarium, 1,500 lbs with sump, pumps, etc., just to have a more meaningful number to work with.

Just to have a benchmark, keep in mind that 1,500 lbs. is more than a typical 9' concert grand piano (Steinway Model D at 990lbs, Yamaha CFIII at 1,100 lbs). A typical home piano might run from 300 to 500 lbs.. Any modern floor should be able to take a 300 lbs. piano. Key word there is should. Some modern homes will flex with what should be a trivial load. What happens if you bend your knees quickly while standing at the place you want your tank to be? Jump up and down? You want the floor to carry the load, but also you want to be able to walk normally instead of having to tip-toe so the floor doesn't flex, rock furniture (I've seen this, with glasses falling inside cabinets, book shelves rocking over, bathroom doors popping open, ...), etc.. 

If your floor is well engineered, well constructed and you have easy access to the floor joists, then doubling up the floor joists and adding solid cross-bracing is a way to address the issue without having an impact on how you use the space in the basement, now or in the future. If you call the builder don't ask if the floor will take 1500 pounds of aquarium; ask if it will take a 1500 lbs. grand piano. Don't expect a quick answer, if you get one.

Jackposts can seem like "absolute" solutions, but if you add one to carry a meaningful load (not just added to feel better), then you should be aware that if loaded they may damage the floor (allowing the post to lower, thereby reducing the load they're carrying or lowering the floor they're supporting) or even crack or punch through the basement floor if the load exceeds what the floor will take at that point. Hint: point (we'll come back to this). When a home is engineered to have a jackpost supporting a meaningful structural load somewhere in the middle of the floor, then before the basement floor is poured, there is a concrete pad - a mini-footing - constructed on the ground below where the jackpost will be. As with the foundation wall footings, this is covered when the basement floor is poured. The basement floor transfers the load to the dedicated footing/pad below the floor. If you're adding a jackpost or other significant load in the middle, you don't have a footing/pad below the floor to take transfered loads.

The base of the jackpost creates a point load, in that the load it is carrying is concentrated to the area of its foot. A 1500 lbs load on a 4" square jackpost foot results in a loading of the full 1500 lbs. at that point on the floor and a little over 93 lbs. per square inch (1500/(4x4)). Put a 6" square wood block under the foot and it's now a little under 42 lbs. per square inch (1500/(6x6)). Well, not exactly, it's concentrated towards the middle as the wood will deform under the steel plate load, but it's close. And the deforming wood will cushion the load such that you don't end up surface differences resulting with the load on, say, the 1 square inch where the two surfaces actually touch, for 1500 lbs. per square inch - a very high point load - very bad. So a block of wood under any jackpost steel foot is a very good idea. A thin sheet of plastic or sill plate gasket between the concrete floor and the wood block, and again between the steel foot, provides a moisture barrier.

The same goes for supporting wooden posts. They should have a suitable footprint to distribute the load. And a moisture barrier.

Put in a small 2x4 wall 4' long with its 2x4 plate (3.75"? wide), and it's down to a nominal 8.33 lbs. per square inch (1500/(3.75x48)). Nominal, because again, it's not exact as most of the load is at the studs unless you place some 2x4s or 2x6s on their side on top of the floor plate to act as a load distributing beam. And instead of 1500 lbs. in one spot, it's distributed over a four foot span of the floor (especially if you made the beam on top of the floor plate). Please use some sill plate gasket to isolate the wood from the concrete, or make sure the entire bottom of the wood plate is covered with construction adhesive (which also means you don't need to nail-gun the plate into the concrete floor). Construction adhesive? Use gloves, disposable recommended, unless you want - for the next week - to look like you were wrestling an alien or have a strange skin disease. Don't ask me how I know.

Hope I did the math right, but you get some ideas to consider anyway. YVMV!

[RossW]

What about using a 12"x12" piece of steel plate instead of the 6" square wood block?  Would it not outlast the wood and do a slightly better job of distributing the load?

Also, where the jack posts meets the joists, does it make sense to also distribute the load there?  How about using 3/4" plywood there, or also steel plate again?  I was considering 6" strips of 3/4" playwood run perpendicular to the joists, maybe 6" apart, glued and screwed in place.

The base of the jackpost creates a point load, in that the load it is carrying is concentrated to the area of its foot. A 1500 lbs load on a 4" square jackpost foot results in a loading of the full 1500 lbs. at that point on the floor and a little over 93 lbs. per square inch (1500/(4x4)). Put a 6" square wood block under the foot and it's now a little under 42 lbs. per square inch (1500/(6x6)). Well, not exactly, it's concentrated towards the middle as the wood will deform under the steel plate load, but it's close. And the deforming wood will cushion the load such that you don't end up surface differences resulting with the load on, say, the 1 square inch where the two surfaces actually touch, for 1500 lbs. per square inch - a very high point load - very bad. So a block of wood under any jackpost steel foot is a very good idea. A thin sheet of plastic or sill plate gasket between the concrete floor and the wood block, and again between the steel foot, provides a moisture barrier.

[ajm1961]

I will check with a few engineers I know, but it seem to me, now that I've had time to reflect on the various input, that if the load is spread amongst 3 or more joists and that it is near to the exterior wall, where the joists are resting on the foundational support, it would be highly unlikely that this additional pressure would make a difference. In this case, my stand would extend no further than about 21" from the exterior wall. There's no way the joists would sag as they are too close to the supporting wall.
But I will double-check anyways to see what would be the consequences over time.
Again, I am glad to read all the advice and debate over the topic, it certainly something to ponder as an aquarist.
Cheers!

[Canoe]

What about using a 12"x12" piece of steel plate instead of the 6" square wood block?  Would it not outlast the wood and do a slightly better job of distributing the load?

Also, where the jack posts meets the joists, does it make sense to also distribute the load there?  How about using 3/4" plywood there, or also steel plate again?  I was considering 6" strips of 3/4" playwood run perpendicular to the joists, maybe 6" apart, glued and screwed in place.

12" square of steel is better than 4" or 6". Better again if it's thick enough to not bend under the load it's distributing. But still use wood between the steel plate and the concrete floor. The wood buffers the load between the steel plate and the floor so you don't get extreme point-loads. Think snow shoes. If it's a large load, stud off-cuts may not be enough, you might need hardwood. Plywood may or may not be strong enough. Depends on the load. I used to see particle board used frequently. However, if this is one jackpost, the entire load is still going onto the floor at the one spot, just the pounds per square inch is improved. Use the moisture barriers and the wood should last a couple hundred years. If you get spring floods from an overwhelmed sump, I'd epoxy coat the wood (and let the epoxy dry) before putting it in place.

I'd assumed that there was a beam under the floor joists, with jackposts, wooden posts or studs supporting the beam. If the beam is stiff enough, a single jackpost could take the load, but will the basement floor? If the tank is four feet long and the beam under the floor joists is six feet long, and you use a beam-on-plate-on-floor six feet long, then two jackstands, each two feet in from ends, would do a nice job. It depends on how much load you'll be transferring from the floor joists to the jackstands and onto the floor. Add a third jackstand in the middle for larger loads? The bigger the load, the more stiff/strong the beam needs to be and the more you need to distribute the load at the floor.

If your tank is going across the floor joists, a beam under the tank running lengthwise should be sufficient. I'd feel better going to the next joist beyond the end of the tank, just because.

If the tank is going along the joists, then I'd be putting in solid cross-bracing where I could. Then if it was my house, I'd want mini-beams running across the joists (like joists under the joists), going to the joist beyond the end of the tank, or even the next beyond if the tank is close to a joist. Where I've done this type of support (although not for aquariums yet), I've laid out the 2x4 or 2x6 mini-beams/joists on the concrete floor below where I want them to support the floor above. Then I glue and screw 3/4" or better plywood onto the mini-beams/joists. You can cap the ends with another 2x4 or 2x6 if you like. This gives you a box, although somewhat heavy, that you can have two friends lift into place while you screw the plywood into the floor joists in a few spots so the screws hold the box in place while you build the final support under it. You can do this without the two friends helping, but only if there is no one around with a video camera and you don't mind risking your back, head, blood-pressure, certain vocabulary, etc.. The support is a beam parallel to the floor joists so that it crosses the mini-beams/joists, with jackposts, wooden posts or a stud wall. If this is in a finished space in the basement, it really messes up the visuals and the finishing effort. Doubling or tripling up the studs and adding cross-bracing makes for a much easier-to-finish basement ceiling; you still have a load distribution issue at the floor when dealing with heavier loads, where you're facing a beam-on-plate wall with internal jackposts or studs, or jackposts with large feet/pads.

I wouldn't glue the plywood or beams to the underside of the floor joists. To much risk of structurally damaging the joists if you ever take the aquarium supports out, say for selling the house.

A stud wall is cheaper. Jackposts are adjustable. DON'T lift the floor higher than it's original height!!!

If you're putting in a larger tank, (400 gallons upwards? I don't know the weight at which you HAVE to check) you'd better be getting an engineer to confirm the load on the main floor and the required support of the main floor. Don't be surprised if you're given the specifications of the footings/pads (yes, that's plural) you'll be putting in under the basement concrete floor, although there may be cases where they'd O.K. a wooden structure looking much like a deck for distributing the load across a large area of the existing concrete floor.

[alexv]

I have a 220 gal tank (regular glass 12-15mm thick) on a wooden stand made of some 2x4s (rather heavy) sitting along an outside wall across the floor joists. So far nothing bad has happened. I hope it stays that way

Our house has engineered floor joists (it's rather new - just about 4 years old)...

[Canoe]

... if the load is spread amongst 3 or more joists and that it is near to the exterior wall, where the joists are resting on the foundational support, it would be highly unlikely that this additional pressure would make a difference. ..There's no way the joists would sag as they are too close to the supporting wall....

Probably not an issue, IF it was designed to code and BUILT to the design, without shortcuts, errors or defective materials. I've seen modern premium houses that had front rooms that were so poorly engineered or built that:

• a bookcase sitting on hardwood (not floating floor) on an outside wall fell over from young kids jumping in the front room (it missed),
• walking in a front room where all the cabinets in the room would shake and rattle glasses just by anyone walking through the room - they couldn't keep any vases or such on top of any cabinets, etc.,
• party of ten in a front room (foundation on three sides), a few decided to start dancing and the entry-way bathroom door (15 feet away, one wall on foundation, door not facing the audience) popped open and the dancing stopped to steady various cabinets (on thick wall-to-wall carpet).

The floor structures weren't built properly.

One was an executive townhouse with a large footprint that didn't have the joists on top of the foundation, but on a 2x? bolted to the foundation supporting one end of the joists and the other end of the joists were supported by an independent stud wall. ?!?? Architect/builder/owner was renting it out.

Assuming the tank isn't huge, try the simple jump test. You might feel good to go after that or you might be going "I'll add some bracing and check again", or even "oh my, catch that - I need an engineer". People have had problems from a piano. Some tanks weight more...

I would recommend NOT doing a jump test beside an already filled tank. Only at a location you're considering putting a tank.

YRMV