Floor under the DT issue

[awais98]

Im not sure if Im imagining this.

When ever my son runs around the living room DT, I feel like there is more percussion and some sway on the DT then Id be comfortable with.

So I decided to check my joists, which look fine.

Researched about strengthning the floor and then I found to my dismay that the best config for the tank would be to be sitting perpendicular to multiple joist, near a weight bearing wall....

Now my problem, its sitting parallel to the joist resting on at best 2 joist, almost near the middle of its 16 feet span, next to a partition wall/stair case!

Before I started all this I had casually asked someone if this Dt would be ok on first floor and was told its not too big just keep near a wall , itll be ok.

Now Im thinking about sistering those 2-3 joist and also putting up a small wooden beam and 2 lally columns on 2 sides of my sump. ( if you rememebr mysetup, DT in living room and sump in the basement, pretty much below the DT)


Sistering end to end 16 feet would not be easy especially with cables etc running between the joists

What you guys think? best solution? Experience?

 

[woodnaquanut]

Sistering will have minimum effect on such a long span. Added to that the difficulty of re-routing all the pass thru items.

Your best bet would be to add beams perpendicular to the joists with support to the floor below. This will go a long way to making the floor stiffer so your boy can let loose and not worry about a flood!

Do you have any pictures of the basement structure?

 

[sleepydoc]

So you've got 1000+ pounds resting on 1, maybe two joists and the rest supported by the underlayment of unknown quality in the middle of a 16' span of a joist of unknown size. No wonder it bounces. And every time it bounces, all the joints in the tank are likely flexing slightly as well.

No one here can say for sure what a safe solution would be. I can say that what you have isn't. The best solution would likely be to turn the tank 90º and put a support wall under it. Beyond that, you need to have someone qualified look at your construction.

 

[Speed]

Consult a local structural engineer sooner rather than later, not the great group of well intentioned folks on a reef keeping board.

his rate to advise you on correcting it will pale in comparison to the possible long term damage it could do. it would really stink to come home and find your tank in the basement or worse yet, have it happen while your sitting in you recliner enjoying a beverage.

that being said, I agree with woodnaquanut.

saw this in another thread on this subject. Take a peek...

http://badmanstropicalfish.com/articles/article28.html

 

[Alberta-newb]

I'm currently in a similar situation. My layout sounds about the same except I have a shorter 12' span. I've consulted an architect and we've come to the decision I need to "sister" two joists (they are on 16" center and old growth fir). The "sisters" though will be either HSS (hollow structural steel) or actual "I " beams. One end of each will be right on the foundation, the others on the main beam. In addition, an additional jackpost will be required under the main beam. The DT will be over 6000 lbs (about 250 psf vs. the 50 psf my current floor is rated for. It's a lot to sort out, so I recommend finding a structural engineer and follow their advice. Every home/tank is a unique situation.

 

[awais98]

Thank you for all your input.
My current joists are 2"x12"x16', 16 inches apart.
House is not old abt 10 years.

Underlayment is 3/4 Mdf like everywhere else, on top of it is solid hardwood perpendicular to the joists.

Here are some pics:

 

[awais98]

 

[awais98]

Thank you for your input.
Your engineer just reinforced what I had planned to do. Sistering 3 joists and 2 perpendicular beams under them supported by 2 lally columns( jack post).

Not trying to say Im an engineer, I'm not; but educated enough to research that the best or most you could do is exactly that: buttress the joist by sistering and support them by heavy columns. What more could anybody do, without changing the current config?

I'm currently in a similar situation. My layout sounds about the same except I have a shorter 12' span. I've consulted an architect and we've come to the decision I need to "sister" two joists (they are on 16" center and old growth fir). The "sisters" though will be either HSS (hollow structural steel) or actual "I " beams. One end of each will be right on the foundation, the others on the main beam. In addition, an additional jackpost will be required under the main beam. The DT will be over 6000 lbs (about 250 psf vs. the 50 psf my current floor is rated for. It's a lot to sort out, so I recommend finding a structural engineer and follow their advice. Every home/tank is a unique situation.

 

[awais98]

I completely agree with you
But just to appease the mind with some labor, sistering AND beam/ column supporting would go a long way for peace of mind.

Sistering will have minimum effect on such a long span. Added to that the difficulty of re-routing all the pass thru items.

Your best bet would be to add beams perpendicular to the joists with support to the floor below. This will go a long way to making the floor stiffer so your boy can let loose and not worry about a flood!

Do you have any pictures of the basement structure?

 

[DerekFF]

http://www.reefcentral.com/forums/showthread.php?t=2310672

 

[awais98]

Derek thanks for the link, can u share pictures of your work?
Thanks

http://www.reefcentral.com/forums/showthread.php?t=2310672

 

[DerekFF]

Oh just saw this reply. I was just under the house today lol. Crap. Guess ill go back into "the hole"

 

[don_chuwish]

How heavy is the DT and what are the dimensions? There may be someone on here with enough structural engineering knowledge to give solid advice, but they'd need to know those numbers first.
I'm working with an engineer/draftsman right now on a house design and it's amazing how quickly he can run numbers in his head. How much weight a given structural element can support at a given span, etc., including the assist from the OSB floor sheeting, for example. I'd strongly suggest paying for that professional advice - they can not only make sure it'll be OK but also help avoid overkill.
If you're going to just DIY it though and do sistering + columns, you could cross brace or solid block all the joists instead of trying to run a long sistering 2x10 (or whatever). Cross blocking joins the joists so they better share the load and you won't have to worry so much about the pass through wiring, etc. A couple of interesting links:

http://www.youtube.com/watch?v=R_OF9KgWhzI

http://www.doityourself.com/stry/floor-joist-cross-bracing

Good luck!

EDIT: Cross bracing/blocking AND posts I mean. Not just one or the other.

 

[awais98]

Thanks for your reply. interesting links.

The more I ruminate about it, I think, Just putting 2 columns on each side would be more then enough.

How heavy is the DT and what are the dimensions? There may be someone on here with enough structural engineering knowledge to give solid advice, but they'd need to know those numbers first.
I'm working with an engineer/draftsman right now on a house design and it's amazing how quickly he can run numbers in his head. How much weight a given structural element can support at a given span, etc., including the assist from the OSB floor sheeting, for example. I'd strongly suggest paying for that professional advice - they can not only make sure it'll be OK but also help avoid overkill.
If you're going to just DIY it though and do sistering + columns, you could cross brace or solid block all the joists instead of trying to run a long sistering 2x10 (or whatever). Cross blocking joins the joists so they better share the load and you won't have to worry so much about the pass through wiring, etc. A couple of interesting links:

http://www.youtube.com/watch?v=R_OF9KgWhzI

http://www.doityourself.com/stry/floor-joist-cross-bracing

Good luck!

EDIT: Cross bracing/blocking AND posts I mean. Not just one or the other.

 

[hllywd]

Sistering will have minimum effect on such a long span. Added to that the difficulty of re-routing all the pass thru items.

Your best bet would be to add beams perpendicular to the joists with support to the floor below. This will go a long way to making the floor stiffer so your boy can let loose and not worry about a flood!

Do you have any pictures of the basement structure?

This is the simplest, most effective solution you could even do today. I'd locate the position of the tank and add a piece for 4"x4" perpendicular to the affected joists supported by a post as close to each end of the tank as possible. For posts I'd use a couple 4"x4"s with shims tapped in at the top to make them snug, not even a need to spend the money on jack posts, 3 - 4"x4"s, a pack of shims, and a few nails and the floor will be rock solid. If the tank is resting on 2 - 12" I-joists with 3/4" T&G OSB and 3/4" hardwood on top of that the braced floor will be plenty strong for a 120.

 

[awais98]

Thanks you for the reply.

Seems to be this will be plenty! All I need is confidence building with two posts.
The floor is fine currently, the boy is continuing to run and the house is only 10 yrs old.
I might just get 4x6s or 6x6s....for the posts.....

This is the simplest, most effective solution you could even do today. I'd locate the position of the tank and add a piece for 4"x4" perpendicular to the affected joists supported by a post as close to each end of the tank as possible. For posts I'd use a couple 4"x4"s with shims tapped in at the top to make them snug, not even a need to spend the money on jack posts, 3 - 4"x4"s, a pack of shims, and a few nails and the floor will be rock solid. If the tank is resting on 2 - 12" I-joists with 3/4" T&G OSB and 3/4" hardwood on top of that the braced floor will be plenty strong for a 120.

 

[Jonviviano]

Sistering joists will do NOTHING if the tank already has the weight on the existing joists. the existing joists are already under stress. you would need to remove the load on the original joists, sister another on then put the weight back on

 

[Eud]

Here's what I just did this weekend for a 75 which was in place on a springy floor, but empty, so there was maybe 150 pounds of load on it.

I sistered in two 12 foot joists from beam to sill plate, then glued and screwed up a 4x6 piece of 3/4 plywood to the center of the span where the bending moment is highest.

 

[hllywd]

Thanks you for the reply.

Seems to be this will be plenty! All I need is confidence building with two posts.
The floor is fine currently, the boy is continuing to run and the house is only 10 yrs old.
I might just get 4x6s or 6x6s....for the posts.....

4x6s or 6x6s won't hurt anything, but in my opinion will be a lot of overkill. I would secure the two short pieces across the joists near the ends of the tank, you should be able to toenail into the bottom chord of the I-joist, then place the posts, tap in a couple shims at the top, and toenail the assembly together so the posts can't fall over if they loosen. Not really much to build, basically a T-post. In a few weeks when the lumber shrinks you may need to tap the shims in further, but IMO your fix is really this simple. Look at it this way, the tank is already supported, all you want to do is eliminate the deflection in the existing floor caused by the concentrated load of the tank.

 

[awais98]

I understand the sistering but where does the 4x6 plywood help? i think it was not required. If you still needed more, you could have jus put some posts to support the sistering joists. IMHO

Here's what I just did this weekend for a 75 which was in place on a springy floor, but empty, so there was maybe 150 pounds of load on it.

I sistered in two 12 foot joists from beam to sill plate, then glued and screwed up a 4x6 piece of 3/4 plywood to the center of the span where the bending moment is highest.