Tank weight vs house construction

[chimpsnest]

Hi all, I realize that these questions have been covered numerous times, but I haven't seen anything that resembles my situation. What I need is somebody familiar w/construction I suppose.

I want to put a 60 gallon tank along an outside wall on the 2nd floor of my house (tank = 48" long. framing = 2 x8 16" OC) Framing runs front to back on 2nd floor, tank stand would span across about three joists. Can't remember if tank stand is four legs, or solid frame on bottom (it's still @ the store).

The dilemma is that the 2nd floor of my house bumps out 2 feet from the first floor (ie garage/first floor level = 26' deep and 2nd floor/fish tank level = 28' deep). No option for tank on 1st floor unless I want it in garage or entry area.

I'm not certain that the 2 x 8 joists run from the front of the 2' bump out all the way back to the steel beam in the center of my garage -OR- if they ran the joists from the steel beam to rest right on top of the frame of the garage doors, then separately put in joists to frame the bump out on its own. I would think the 2nd scenario couldn't be the case because the front wall of the house supports the weight of the roof and that would mean that weight was supported by a suspended area of 2 x8 's kind of floating 24" out from the front of my house.

I've linked to some construction shots from when the house was built in hopes of finding my answer (I also have more pix @ home that I hope will yield more construction info for me - and I have my plans too, but I know what's on paper doesn't match the final build exactly). Hopefully my cheesy MS Paint rendition of the construction helps illustrate what I mean along w/the pix. click on the pix to look closer and get my descriptions.

chimpsnest/Aquarium - Photobucket - Video and Image Hosting

At one time I had a 55 gallon aquarium upstairs in a hallway of a cape style house, but it was on a load bearing wall.

Any help or suggestions or construction input is appreciated I just don't want to mess up my new house in a HUGE way!

 

[Zagz]

My best opinion would be to check with the builder. We can offer opinions but since a lot is riding on the answer, the builder would be the most accurate bet. My opinion is there would be no problem.

 

[BillD]

I'm a little rusty with the necessary calcs and don't have easy access to my strength tables but, I would xpect that the load rating for that bit of floor on the overhang would have to be at minimum the same as the rest of the floor. If 4 of your biggest friends stood together on that section of floor would you expect a problem? My guess would be that you would be fine, especially if you kept it inside a bit and spanned 3 joists. If the stand had 4 legs I would be inclined to set it on a 2 x 4 frame just to distribute the weight more evenly. This of course is only an opinion, and I have not done any calculations or checked any of the tables.

 

[jsoong]

Where exactly would you be putting the tank .... in relation to the garage doors?

I think you should talk to a structural engineer or the builder to be really sure.

Looking at your pictures, it appears the joists runs all the way front to back (at least on the right side - not over the garage doors). If you have not covered the garage ceiling, you should be able to see how the joists are placed over that section. <Building code would mandate the joists over a cantilevered section to run back all the way to the middle support .... I know, as the building inspector for my addition insisted on us tearing out the drywall to see that it is so .... but you prob should be certain that is true in your case.>

My worry however, is if you place the tank over the garage door opening. That section of the floor joists rests on a beam (size?) which is supported by a stacked 2x post (I counted 6 2x lumber in the center post ... is that 2x4 or 2x6?) The critical part of the construction is actually the beam across the garage door, as that is supporting the entire front of the 2nd floor (plus the roof). If you place a tank directly in the middle of the beam (at the midpoint of a garage door opening between the 2 posts), that may sag the beam enough that your garage door might not open/close properly. A small tank like a 60 is UNLIKELY to cause this, but I am no structural engineer & I don't know your beam size/structural strength ... etc.

I think sagging is your main worry, it would be quite unlikely to have a structural failure. Then safest spot over the garage doors is to have the tank directly on top of the middle (or one of the side posts), as those are load bearing elements that directly connect to ground.

 

[HooKooDooKu]

I'm going to go with jsoong on this one.

I'm not very worried about the joists because as others have pointed out, they would almost HAVE to be solid joists from the beam out over the garage doors. But as others have indicated, you should be able to check this out yourself from the garage. If the joists are still exposed in the basement, then you should be able to easily determine if the end caps as seen from within the garage are cut and nailed between joists (almost a certainty) or is the end cap solid with joists ending and restarting at the garage.

But my biggest concern would be that point load over the garage door.

I know that for my house, the builder insured the upstairs garden tub was properly supported by framing a closet under the upstairs tub.

In your case, it's the fact that you want to add a point load to a wall that is already... full of holes... is my concern.

Assuming 24" hang over joists are solid, I would want to sister another board to the header over the garage door to strengthen it to avoid the sagging jsoong was talking about... and it wouldn't hurt to sister the 1st stud on each side of that same garage door.

 

[jcarlilesiu]

Im an Architect... see if I can help.

I am with most of the others here. Because the floor at the 2nd level extends beyond the front face of the 1st floor (at the garage opening location), the floor must be rated by code to the same capacity as the rest of the room, or the non-cantilever portion.

It would be extremely difficult to frame this without running the joists all the way back to the center support beam. That beam is most likely located under the ridge line of the roof and picks up the mid-span loads from both the front and back of the house. Framing that cantilever any other way would be extremely difficult and costly... you would have remembered.

Placing a 60 gallon aquarium across 3 joists shouldnt be a problem in my opinion. That is well about 600 pounds (estimated) with tank, equipment and water. 200 pounds per joist, especially with bridging installed between joists shouldn't be too much for the 2 X 8s to handle.

I disagree with what somebody else talked about in regard to the header at the garage door. Those built up 2X headers are designed to carry the floor load of the level above, plus the snow load of the roof, all the way across the entire span of the opening. Infact, because that header is installed almost UNDER your aquarium is beneficial to your cause as the load doesn't have to transfer to the exterior wall before transfering to the foundation.

Of course, your milage may vary, and I don't take any responsibility for my advice either implied or otherwise (makes my E&O insurer happy when i say that)... but in my opinion, you should have no problem.

 

[HooKooDooKu]

...
I disagree with what somebody else talked about in regard to the header at the garage door. Those built up 2X headers are designed to carry the floor load of the level above, plus the snow load of the roof, all the way across the entire span of the opening. Infact, because that header is installed almost UNDER your aquarium is beneficial to your cause as the load doesn't have to transfer to the exterior wall before transfering to the foundation...

Jcarlilesiu is correct in that header is going to be pretty strong and likely nothing special has to be done.

However, my personal concern is that when these things get sized, they are usually based on calculations that usually assume spread out loads. So when that header is holding up the snow on the roof, that snow load is distributed accross the entire length of the header as well as the parts of the wall beside the garage door.

Relatively speaking, the fish tank is going to be a point load. Now the reason to insure the weight is across at least three floor joists is to help insure the load is spread out, and that's all that might be required, especially if the tank more to one side of the garage door rather than right in the middle of the span. But if it's close to the middle of the span, and the header is still easily accessable from the basement, it won't cost much to sister that header (basically, screw another piece of wood to the side of the header) to insure you don't get too much flexing of that header.

Now I would be EXTREAMLY suprised if that header ever failed if you did nothing. I don't think failure of the beam is an issue. But it's the flexing and bowing of that header over time that would consern me.

If the header isn't easy to reinforce with a sister joist, then just concentrate on spreading the load. Either get a cabinet that is oversized to spread the load on to more floor space, or try to position it such that the tank sits above 4 floor joists rather than just 3. If you have a standard 48" tank with 16" spaced floor joists, then you should be able to place the tank such that the left and right side is sitting right over a floor joist, with two more in between.