Do I Need Floor Supporting?!?

[Averhoeven]

Do not worry about bridging, it is required for trusses, not joists. I-Joists that you have are to be treated as standard joists and would only require blocking for the diaphragm, which you probably don't need or it would be there already. I-Joists are indeed stronger than standard similar sizes wood joists and they deflect less.

Does the floor feel bouncy when you walk on it now that the tank is full? If not, you're probably fine. If you're still worried, let me know the depth of the joists the tank is sitting on, the size of the flange of the joists (the larger top and bottom peices) and the thickness of the web (the plywood piece connecting the flanges, the piece with the stamp on it you took a picture of).

I have since emptied the tank as I was just leak testing it at the moment, but I don't recall any bouncing at all. The hardwood floor underneath it did not appear to be bending under the weight either. My level had the whole thing as straight as well.
I made this diagram for another user who offered to help and take a look, but thought it might help here too. I am genuinely very appreciative of all the help. People have gone way above what I could have ever imagined.

 

[Windy]

Do not worry about bridging, it is required for trusses, not joists. I-Joists that you have are to be treated as standard joists and would only require blocking for the diaphragm, which you probably don't need or it would be there already. I-Joists are indeed stronger than standard similar sizes wood joists and they deflect less.

Does the floor feel bouncy when you walk on it now that the tank is full? If not, you're probably fine. If you're still worried, let me know the depth of the joists the tank is sitting on, the size of the flange of the joists (the larger top and bottom peices) and the thickness of the web (the plywood piece connecting the flanges, the piece with the stamp on it you took a picture of).



Against that corner where the stairs are? Should be no issue. 120 gallons is not a problem.

"Floor joist bridging is critical to the structural strength of a floor, as shown in Figure 1. ... When cross bridging is used, wood or metal, the upper portion of the bridge is nailed into the top of the floor joist, if it is metal." You don't know what you are talking about!

 

[Erica-Renee]

I will just leave this here , Thou what do i know I have no engineer degree.

http://www.renovation-headquarters.com/floor-joist-bridging.html

this is not the best information but it has good Diagrams ...

 

[OriginalUserName]

also with them being close to that wall has no bearing on how much they hold.
...

Can you explain why that is the case? If the load is centered over a joist's span vs centered a few inches from where the joist rests on the sill plate, isn't that a very different situation? Not arguing, I just want to know what I'm missing as I'm in a very similar orientation.

 

[Erica-Renee]

Can you explain why that is the case? If the load is centered over a joist's span vs centered a few inches from where the joist rests on the sill plate, isn't that a very different situation? Not arguing, I just want to know what I'm missing as I'm in a very similar orientation.

Say your tank is running Length wise With the Floor joist with one of the joist running center of the tank , The tank is in the middle of the span of a 14 ft long room.. Nearly all of the weight of the tank is resting on that one Floor joist.The floor decking will distribute some of the load to each joist.If there is proper bridging across the entire section from band to band This ties them together even more. Even of say that joist is 16 inches off the wall that one joist is supporting most of the load..

If your tank is running across the Joist span. Say tank is sitting on 4,5 joist that are sitting on seal plate/Foundation walls . And your tank is next to the wall. You are putting the weight of the tank across all joist under the tank. Spreading the weight better. Of Course again Proper bridging will help transfer the weight just like above but has less of a impact.

So if your tank is running long ways with the Joist . Extra support is almost a MUST for larger tanks. If the tank is running across the Joist span resting on multiple joist against there resting wall -foundation wall. Your tank is on the strongest position of the floor..

NOW...

IF your joist are running from a beam to a Foundation wall. and the tank is spanning across multiply joist your are distributing the weight on many joist but also onto that beam , This may cause the beam to sag . Beam may need reinforcing.. Joist hangers or method connected to beam ( sitting on beam, Joist hangers . TYPE Of hangers and so in NEED To be Carefully Considered into the Equation... The same goes for But even more so if the tank is running with the joist in in a room and resting long ways on one joist. that is connected to a beam not a wall or foundation wall..

 

[OriginalUserName]

I've decided to go ahead and sister the joists directly under the tank and then add 2 floor jacks with a beam stretching across several joists. That will be an overkill but it's not like this will be expensive for difficult. I think I will place the jacks under the far end of the tank which will effectively change the span of the joists under the tank from 10' to just 5ft (from sill plate to the jack).

 

[OriginalUserName]

So I won't be able to fully sister the 2x10 joist due to some plumbing. My plan is the cut the 2x10 at about the end point of the tank and sister it that way. Under the cut I will place 2 floor jacks using a doubled up 2x4 (glued/nailed together) to bridge 3-4 joists and supporting directly under the end of the tank/cut 2x10. The joists aren't bridged so I'm going to bridge 6 or so under the tank area. Does anyone see any issues? I think the jacks on their own would probably be sufficient but since I already have the 16' board in the basement I may as well use it. Obviously just sistering a cut beam does nothing, but if I'm supporting the area under the cut this should act as if I just have a 6ft span instead of a 2 foot span.

first pic shows what I'm thinking in terms of the new joist pieces. Second shows how the tank hits the joists (unfortunately just over 1 which is why I definitely need support)

 

[Windy]

2 x 4's aren't going to give much stability from the posts. You need a 2 x 10 or 2 x 12 on top of the posts. If you look at standard framing, doubled 2 x 4 's are going to sag over more than 16" of span.

 

[OriginalUserName]

2 x 4's aren't going to give much stability from the posts. You need a 2 x 10 or 2 x 12 on top of the posts. If you look at standard framing, doubled 2 x 4 's are going to sag over more than 16" of span.

Ok thanks, I have extra 2x10 I can use for the top of the posts so I'll go ahead and swap them out tonight. I do have the base of the posts resting on 2x10 pieces to spread out the pressure on the concrete floor a little.

I ran into some problems with sistered joist. I got it into place and the board was flush near the exterior wall but about 1/4" lower at the support point. I assumed I had it installed incorrectly, but after taking it back down it seems like the existing joist is cut a little narrow or bows upward a little. It didn't seem right to have just the new sistered joist resting on the support.

I'm positive that two jack posts connection to 3 joists right at the end point of the tank, combined with adding bridging to the surrounding joists will be sufficient to hold up the tank. I guess I'll know soon enough.

 

[SeaJay]

I just got finished with a floor reinforcement project to support my new tank. The tank sitting parallel to the joists was going to leave pretty much the whole load on one joist. I have 12" engineered joists, so I made a beam out of a 2x10 and a couple of 2x4 and placed that between the joist the tank is resting on and the one it doesn't quite reach. Then I built a 2x6 deck and framed walls around the perimeter. This carries the entire load of the tank down to the basement slab and should ensure that I never have any issues. It may be overkill, but I'd rather be safe than sorry. The room is going to be finished off as a rec room for the kids, so I'm going to hang the TV on it and use the space for storage and to hide electronics.

 

[OriginalUserName]

I just got finished with a floor reinforcement project to support my new tank. The tank sitting parallel to the joists was going to leave pretty much the whole load on one joist. I have 12" engineered joists, so I made a beam out of a 2x10 and a couple of 2x4 and placed that between the joist the tank is resting on and the one it doesn't quite reach. Then I built a 2x6 deck and framed walls around the perimeter. This carries the entire load of the tank down to the basement slab and should ensure that I never have any issues. It may be overkill, but I'd rather be safe than sorry. The room is going to be finished off as a rec room for the kids, so I'm going to hang the TV on it and use the space for storage and to hide electronics.

Looks very well built. Install some slide out shelves in there for your electronics and you can really use the space.

 

[SeaJay]

Looks very well built. Install some slide out shelves in there for your electronics and you can really use the space.

Thanks, I didn't think about slide outs. I'll have to google around for some ideas. I put the studs 12 on center so I kinda limited myself on what I can do across the front. Pretty much everything will have to be accessed from the sides.

 

[Windy]

Your job looks great, but it's way over-built. I am an engineer and have framed homes as well. If I were you, I would double that header over the middle of the wall, and remove the two center studs so you have a 3' doorway. A double header over a 3' opening is very strong and now you have a useable closet.

 

[Windy]

 

[Art2249]

Haven't read through all the posts but I have built a lot of houses. From my experience, engineers are mostly full of it. Unlike other branches of science which require precision, Engineering is a science of "barely good enough to prevent failure>" Failure happens a lot in the "science" of engineering. Wiil the floor hold your tank? Probably. But what about 5 years from now? Wood will fatigue much faster than steel. And you don't need to build a sophisticated structure under your floor joist. A few strategically placed 2x4 will often do the trick.

 

[SeaJay]

Your job looks great, but it's way over-built. I am an engineer and have framed homes as well. If I were you, I would double that header over the middle of the wall, and remove the two center studs so you have a 3' doorway. A double header over a 3' opening is very strong and now you have a useable closet.

Thanks. It's one of only two walls I can hang a TV on in that room. If I decided to hang the TV on the opposite wall I will certainly take your advice. The tank was on the way, so I was up late the night before just trying to get it done and didn't think that far ahead.

 

[Art2249]

Thanks. It's one of only two walls I can hang a TV on in that room. If I decided to hang the TV on the opposite wall I will certainly take your advice. The tank was on the way, so I was up late the night before just trying to get it done and didn't think that far ahead.

You did a great job. Nice framing!

 

[SeaJay]

You did a great job. Nice framing!

Thank you.

 

[Erica-Renee]

You did a great job. Nice framing!

I agree thou the header was WAY above what was needed.. Still tight framing with no gaps. It drives me Batty when i see huge framing gaps ,Bad Cuts and mostly TO MANY NAILS....

 

[kalare]

While I'm sure you're just trying to help, I would recommend that nobody follow the above table, as there are way too many variables to have a "rule of thumb" for header size vs. length, especially if we're talking about putting a tank over them.