I have a wall that goes 3/4th of the way to the ceiling between my living room and dining room. I would like to put a fish tank in it, spanning the length of the wall.

I have the engineering skills to build the tank, but I don't know much about actually placing it in the house.

The tank will be 12x2x2 in size, so I'll need to cut a hole 12'x3' into the wall.

I'm concerned about two major things: I need the surface that the tank sits on to remain smooth to evenly distribute the weight, and the other is the weight.

This tank, once filled and assembled will likely weight close to 3500 pounds. What do I need to do to insure that there won't be any problems with the wall, floor, or anything else to support that much weight. The wall is on the first floor of the house, is not load bearing, and the foundation is a concrete slab.

  • Does the wall sit on the concrete foundation, or is there anything else between?
    – BMitch
    Sep 18, 2012 at 13:09
  • I don't know. How could I tell?
    – Malfist
    Sep 18, 2012 at 13:09
  • You can open a hole in the wall to inspect, you'll end up taking the entire thing down and building a new structure anyway. But you can infer the answer if you know the level of the foundation and of the floor. If there's a 8" difference or greater, you're likely on some joists and not directly on the foundation.
    – BMitch
    Sep 18, 2012 at 13:35
  • See also: Building an aquarium in the wall
    – BMitch
    Sep 18, 2012 at 13:57
  • Is it upstairs or downstairs? If upstairs, there are many other factors to consider, like trying not to bring down the whole house. NEVERMIND I just finished reading. Still, it's important to know for anyone reading this.
    – diy user
    Sep 22, 2014 at 21:54

3 Answers 3


Static load affects structures much differently than dynamic (moving) load. A dynamic load will give periods of relaxation for members to return to their previous shape. A static load will promote bending. Considering the pressure and surface area, you basically need this to sit on your slab. The tank can't take pressure, and you don't want the tank pulling your house down via the wall it is attached to, so for the house, you're basically building a 12 foot wide door, and a tank that's just under the door frame.

The rest is planning for eventual water spill and easy maintenance.

Most aquarium frames capable of holding a 2 foot by 2 foot cross section aquarium are made from 2x4 with 3/4 inch plywood facing. They use a ladder frame for the top and bottom, and have vertical members spaced every 2 feet. The exceptions to these rules include removing every other run in the floor frame (to accommodate sump equipment) and ever other riser on the access side of the frame (to accommodate repairing / replacing the sump equipment). Reinforce the frame as you see fit (most are very overbuilt), as skimping on a little extra 2x4 can buy you a lot of sleepless nights.

Build a pan into the frame if you can. Build a drain into the room if you can. Keep in mind that you'll need storage space for water treatment, and access to the top of the tank. The best solution is a "aquarium closet" with an extra tank just under 1/2 the size of your aquarium. If possible, build that room like a shower, with a central drain, and greenboard around the floor area. In the event that your aquarium develops a leak, it will probably do so when you're on vacation :)

Pay attention that the frame is level and solid on the floor. After you fill the aquarium it will not rock, but those warnings about static load apply to the frame too. If the frame bends, the glass sheets will encounter stress along the seams, and you will get a leaky seal between the sheets.

Ironically, at your size you really shouldn't be messing with anything except a reef-ready tank, which conveniently comes with holes drilled in the bottom :) (for those who don't know, that's a good thing as sump equipment is stored below the aquarium)

  • I won't be needing a sump, my tank is freshwater. I'll only need to hide the canister filter. A drain would be overkill, in my opinion. The back side of the tank will be in the dining room which is next to the kitchen. I can drain/refill from a waterchanger that stretches that far. (i.e. a python) I had already planned on leaving some space open below for the canister filter and supplies.
    – Malfist
    Sep 18, 2012 at 16:40
  • There are a lot of ways to set up a tank. A sump works well for freshwater too, if you go that route. Glad to hear you have a conveniently located kitchen. A large tank can generate enough noise that TV watching and conversation becomes difficult. Keep in mind that you can better soundproof the bottom of your aquarium than the top, and Reef ready will keep stuff from hanging off the side, if that is a concern.
    – Edwin Buck
    Sep 18, 2012 at 16:51
  • The only thing I can think of that would need to be on the side would be a heater. Which a sump would get rid of it, or I might be able to get a inline heater for the canister filter....need to do research
    – Malfist
    Sep 18, 2012 at 16:55
  • This answer is better than I could have said. Good answer.
    – diy user
    Sep 22, 2014 at 21:56

Assuming you're directly on the foundation and don't have to worry about how load bearing the floor is, this should be doable. You'll end up removing the wall that's there today since it won't be structured to support the tank. The new structure can be framed similar to two windows and a short floor in the opening. Here are a few tips off the top of my head:

  • When opening the existing wall, check for electrical, HVAC, plumbing or anything else that may be running inside. You will either need to relocate this or incorporate it into your new wall.

  • You don't want untreated wood in high humidity or in direct contact with concrete. Either use pressure treated or a moisture barrier.

  • If you use pressure treated, make sure you use treated fasteners since PT wood will chemically react with normal nails.

  • I'd space the cripples below the window frame every 12" to spread out the load distribution as much as possible.

  • For the floor you build under the tank, I'd recommend 3/4" plywood resting on joists that are spaced at the same 12" to transfer the load directly to the cripples below.

  • Above the window frame, since this isn't carrying any load, you may be able to get away with a 2x6 over the 12' span.

  • When framing this, don't forget to account for nailing surfaces for drywall at every corner (especially the inside ones).

  • For drywall, make sure to use something that is mold and mildew proof. Green board is good, but they make stuff that's better than that.

  • Use the fiberglass tape on the drywall since it resists mold.

  • I'd protect any outlets at this wall with GFCI.

  • Will I need to remove the entire wall, or can I open up the lower half, reenforce it, and leave the upper half alone?
    – Malfist
    Sep 18, 2012 at 14:05
  • 1
    @Malfist When you remove a 12' span, the top half will fall. Building it from scratch will be faster, better, and easier than trying to retrofit what's there today.
    – BMitch
    Sep 18, 2012 at 14:23

3000 pounds is a load of weight to add, you'll need to make sure that the weight is transferred to the slab, not the wall. If the wall is not load-bearing then it will not be strong enough to hold up that kind of weight, so you'll have to pull down the wall, or at least the sections where the tank will go.

The main thing you need to solve is how to get the weight distributed from the bottom of your tank to the slab without your house's frame having to support it. Is your floor the slab itself? If it's a concrete slab foundation then it may be that the slab is the ground floor, or is just below a layer of flooring. If that's the case then all you need to do is build a strong frame (think pairs of 4x4 pieces here with 1" ply on top as a base for the tank) on top of the floor to hold the tank, then re-build the wall around it.

If your ground floor sits on joists on top of the slab things are a bit more complex. The joists may sit directly on top of the slab, touching along their entire length in which case you don't have to worry, but if there is space between the slab and the joists then they joists will need supports between the bottom of the joists and the slab under the tank's length. This will transfer the weight from the tank to the slab without your house frame having to support the weight and prevent structural damage.

The way to tell whether the floor is directly on slab is to measure from the bottom of the window frame to the floor on the inside of the house, then measure from the bottom of the frame to the top of the slab on the outside of the house. If the measurements are pretty much the same then it's on the slab, if there's more than 2 inches difference then you have something between your floor and the slab.

I'd check your local building codes to make sure you can actually do all this legally, and get some help figuring out your home's construction before making any construction plans.

  • Why would a building code prevent me from putting an aquarium in my house?
    – Malfist
    Sep 18, 2012 at 13:49
  • 3
    It's not the aquarium, it's the pulling down walls and adding 3000 pounds to the structure and possibly needing modifications to your foundation that's more likely to be the issue...
    – GdD
    Sep 18, 2012 at 13:52

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