Floor support advice.....

[SPotter]

We just had a new house built that will include a new 360g tank. Our house is on a crawl space and we doubled up the floor I-joists with 16" between each joist in the room where the tank will be. I am a little concerned now because the builder asked me to sign a liability waiver of all damages if the floor should fail only if I exceed the max load capacity(something that I have asked for a specific number and they are working on). The builder says that their engineers say that the floor will be ok but it makes nervous that they want me to sign this waiver.

Details about the tank and where it will sit....
96x36x24 acrylic tank
perpendicular to the joists
6" (external overflow) away from load bearing exterior wall
Tank will sit across 7 doubled I-joists

Do I need more bracing? I am thinking about having 3 piers built to support a 12" micro beam or use cement blocks with jack posts and the micro beam.

Any and all feedback/suggestions are greatly appreciated!!!!

 

[hijinks]

Te strongest point will be against the wall where most put their tanks. I think you are ok but I'm not a structural engineer. I'd hire one for a few hundred dollars to take a look for the piece of mind

 

[Da Maui life]

"A liability waiver of all damages if the floor should fail only if I exceed the max load capacity" is standard in the industry and a smart professional knows better not to do so.

 

[Addict0Reef]

There are many variables in determining the safety of I-joist supporting aquaria.

If you draw up a sketch and post it to this thread of:

1. Your floor system including exact location of the aquarium over the joists (orientation already given)
2. Joist span (length of joist between supports - if joist is a continuous span over 3 or more supports provide the dimensions to each support)
3. Joist depth
4. What kind of joist you have (mainly the top and bottom flanges - 2x3 or 2x4 or LVL).
5. Any additional loads the joists might be carrying and location of load (for example a knee wall built on top of the joist that supports roof rafters or trusses)


I can then model your criteria and see if doubled joists will support the load adequately.

 

[SPotter]

There are many variables in determining the safety of I-joist supporting aquaria.



If you draw up a sketch and post it to this thread of:



1. Your floor system including exact location of the aquarium over the joists (orientation already given)

2. Joist span (length of joist between supports - if joist is a continuous span over 3 or more supports provide the dimensions to each support)

3. Joist depth

4. What kind of joist you have (mainly the top and bottom flanges - 2x3 or 2x4 or LVL).

5. Any additional loads the joists might be carrying and location of load (for example a knee wall built on top of the joist that supports roof rafters or trusses)





I can then model your criteria and see if doubled joists will support the load adequately.

Ok here is what I have so far.....

The joist 2"x1.5" thick, the web is 9.5". This for each joist so there are 2 at each location. The span of the joists is 14' where they are attached to an lvl. Each set of joists is 16" a part. The room is 10x12 and the tank will sit on the 10' wall. The room is in the front corner of the house so one of the 12' is an ext wall with a window and the other wall is a full wall going up to the ceiling. They only other items that will be in the room in addition to the tank will a couch, the cabinetry for the tank and me (280lbs of reef addiction).

The builder did put 1/2" plywood in the web of each joist starting at the wall and coming out 48" for additional web support.

I will try to get you a diagram soon.

 

[Addict0Reef]

Ok here is what I have so far.....

The joist 2"x1.5"

We are close to figuring this out:celeb2:, just a few more questions...

So from what I can tell from your spec's you have TJI 210 joists in 9.5" depth.

And if the span of the joist is 14' and the room size is 10'x12' (with the tank on the 10' wall) then you have a wall at the 12' point of the 14' span of the joist.

If so, does this wall support another floor and potentially a roof above or is it simply a non load bearing partition wall (to solve this question you will need to look at the floor and roof truss permit drawings if you have access to them)?

This stuff is fun isn't it? :crazy1:

 

[SPotter]

We are close to figuring this out:celeb2:, just a few more questions...



So from what I can tell from your spec's you have TJI 210 joists in 9.5" depth.



And if the span of the joist is 14' and the room size is 10'x12' (with the tank on the 10' wall) then you have a wall at the 12' point of the 14' span of the joist.



If so, does this wall support another floor and potentially a roof above or is it simply a non load bearing partition wall (to solve this question you will need to look at the floor and roof truss permit drawings if you have access to them)?



This stuff is fun isn't it? :crazy1:

Oh yeah it's so much fun there is a 2nd floor above the room. I'm pretty sure that wall has block underneath it in the crawl space. I have some pictures of when just the foundation was down and I will post them later when I find them.

 

[SPotter]

Floor support advice.....

ok here is a picture of the foundation before the flooring system went on it. I will crawl back under there again tomorrow and take more pictures of the joists and see how the support is on the back wall of the room where the tank will be.





the front right of the foundation is where the tank room is. Where I am standing is just about where the back wall of the room is. 2 rows of LVL's go from the front to the rear of the house. Better pictures to follow tomorrow.....

 

[NanoReefWanabe]

although i am no engineer nor do i pretend to be…but if it where my house i would just put in the couple pads and jack posts along with a the LVL beam you have described, across the front edge of the tank…it is pretty simple to do, just be careful not to apply any upward force to the floor, i.e. make it a tight fit, but don't hammer it in…the floor dropping a millimetre or two (if it even moves with the beam under it) once loaded with tank and on lookers won't effect anything...

as the floor is right now i am sure it would hold the weight as it is about 3500 pounds over a fairly large sq ft area…however, over time creep and fatigue will set in and the floor will begin to deflect and sag…i am sure it would have a bounce to it as well...

 

[radobahn]

Sorry, I don't know if you need more bracing, but we also live in a newer home with about a 3ft crawlspace and was told the floor would hold our 180 with 50g sump. But I still worried about it, especially since the I-joists ran parallel with the tank.

So knowing I'd always wonder about it, I installed these before filling the tank with water.

The 4x6's run perpendicular to the tank and were evenly spaced directly under the stand.

 

[SPotter]

Ok I haven't been able to get back under the house for a diagram or more pictures but the builder said that there's an lvl under the 12ft wall that leads up to the 2nd floor.

 

[sleepydoc]

You said the floor was designed to hold the tank, but yet they can't give you any specs? Most builders have engineers they work with to confirm design specs before they build. If they are having a hard time giving you the specs it makes me suspicious that they didn't use an engineer.

Did you give them weights and dimensions ahead of time?

 

[SPotter]

You said the floor was designed to hold the tank, but yet they can't give you any specs? Most builders have engineers they work with to confirm design specs before they build. If they are having a hard time giving you the specs it makes me suspicious that they didn't use an engineer.

Did you give them weights and dimensions ahead of time?

Yeah I have them the exact dimensions of the tank and where it would be located and an overestimate on the total weight. The builder is saying that there engineers say its more than strong enough to hold the load. I guess I got a little freaked out when they asked me to sign the waiver.

 

[Reefsi]

Most builders have architects they work with, not engineers(simple mishap). Anyways you should be fine, those I-Joists are way stronger than people think. To be honest houses are way overbuilt these days if they follow code. You get your cookie cutter homes that have poor workmanship but the lumber usually exceeds the weights needed by tenfolds.

1 Question
When you mean the I-joists are then connected to a LVL, are you meaning they are joist hangared to the LVL? If so what is the LVL sitting? Cause if that is the case the the LVL is what is carrying the whole load.

FYI, if the tank is going nearest an external wall then you could put 2 tanks there and their would be no worries.
My family has been building custom homes since 1901, 113 years in business!

 

[SPotter]

Most builders have architects they work with, not engineers(simple mishap). Anyways you should be fine, those I-Joists are way stronger than people think. To be honest houses are way overbuilt these days if they follow code. You get your cookie cutter homes that have poor workmanship but the lumber usually exceeds the weights needed by tenfolds.

1 Question
When you mean the I-joists are then connected to a LVL, are you meaning they are joist hangared to the LVL? If so what is the LVL sitting? Cause if that is the case the the LVL is what is carrying the whole load.

FYI, if the tank is going nearest an external wall then you could put 2 tanks there and their would be no worries.
My family has been building custom homes since 1901, 113 years in business!

Thanks for your input here. The I-joists are hangared to the LVL and the LVL is sitting on multiple piers.

I think I will proceed with the way the floor is as is. I will watch it very closely when I fill it up for a leak test.

 

[sleepydoc]

Most builders have architects they work with, not engineers(simple mishap).

Not sure if you mean using an architect is a mishap, or my statement was a mishap. The builders I have worked with have both - architects for the basic design, and consulting engineers for questions such as these. Regardless of who they used, you gave them specific design requirements prior to building. Now they want you to sign a waiver but they can't tell you what the design specs are. I would be concerned too.

There are other concerns besides whether the joist will support the weight - if there is too much spring in it, it can cause an excessive amount of shifting as people walk across the room, potentially weakening the tank.

 

[NanoReefWanabe]

There are other concerns besides whether the joist will support the weight - if there is too much spring in it, it can cause an excessive amount of shifting as people walk across the room, potentially weakening the tank.

that is the same fear i pointed out and would have"¦

$100 dollars worth of wood and posts would go a along way to me sleeping better"¦especially if the joists are hangered to the LVL"¦how many ply is the LVL"¦and hopefully they used N10 nails to hang the joists"¦and a butt load of glue to laminate the LVL"¦or is the beam paralam?

 

[sleepydoc]

that is the same fear i pointed out and would have"¦

$100 dollars worth of wood and posts would go a along way to me sleeping better"¦especially if the joists are hangered to the LVL"¦how many ply is the LVL"¦and hopefully they used N10 nails to hang the joists"¦and a butt load of glue to laminate the LVL"¦or is the beam paralam?

All excellent questions for a structural engineer!

 

[SPotter]

that is the same fear i pointed out and would have"¦



$100 dollars worth of wood and posts would go a along way to me sleeping better"¦especially if the joists are hangered to the LVL"¦how many ply is the LVL"¦and hopefully they used N10 nails to hang the joists"¦and a butt load of glue to laminate the LVL"¦or is the beam paralam?

I think it would take more than $100 worth of wood and posts to add any additional support. If you just put the supports on top of the soil won't that sink into the ground if the floor system failed? I would think that you'd have to pour cement footings and then build the supports on top of the footings.

 

[NanoReefWanabe]

I think it would take more than $100 worth of wood and posts to add any additional support. If you just put the supports on top of the soil won't that sink into the ground if the floor system failed? I would think that you'd have to pour cement footings and then build the supports on top of the footings.

8 bags of concrete is like 25$
8' PT 6x6 is like 15-20$
3 8' 2x10 is another 24 or so bucks"¦
a handful of 4" spiral construction nails is about 2.50$
and a tube a couple tubes of PL premium is going to be about 20 bucks"¦

so with tax you might be over 100$ sorry"¦

you might want to throw in a couple hangers too to tie the posts to the beam they are about 1 each"¦


no need to ask an engineer what the beams and joists are"¦go down and look at them"¦LVL looks like sheets of plywood glued together, parallam looks like strands of wood glued together"¦N10 nails are structural nails specifically used for hanging joists in structural floors and they are clearly marked on the heads for the inspectors to see"¦though i would not trust a single LVL to hold up a floor a couple of them glued and screwed to one and other is a different story"¦if there is a couple glued and screwed and the joist hangers are nailed in with N10's and all the nails are there and everything is doubled up like it was supposed to be great"¦would i trust it not to sag over time to hold a tank and onlookers"¦i would still spend the 100$ and add a mid point support.