Floor Support Design

[BlackTip]

I am in the process of adding additional floor support for my 240g tank and 65g sump. I am already half way through the project, but I thought to seek your advice.

The house was built one year ago. The back of the tank will be against a wall. 6" away from the back wall. A wall on each side 18" away. The floor joists run parallel to the tank. Each joist is 18" apart. 14" high I-Beam type joist (OSB sandwiched between top and bottom flange). The joists run almost 20' between supports. With original support, the tank will be on one single joist.

What I did/doing:
1- Install 2 additional joists. The weight of the tank will rest on 3 joists. Each joist will be 8" apart.
2- Run 3 perpendicular support beams. Each beam is made of 3 pieces of 2X6 treated lumber. The beams are 48" long.
3- add 3 house jacks under the beams. The house jacks will rest on 16X16X10 poured concrete footings. And a 16X8X4 concrete block.

I am working on a crawl space that is 26" high. I'd have liked to dig deeper footings , but it took me 5 hours to dig 3 holes. The soil is very hard.
The support beam on the edges will be within 6"-8" from the edge of the tank. I wanted to place the edge support beams at the edge of the tank, but I was afraid my calculation is wrong and left some room for error.

What I have done already is: installed the additional joists, dug the holes for the footings, and assembled the cross beam support.

Here is a a diagram to domenstrate my design. Please let me know if this will work, or will I have 300g on the floor.

Thanks,

 

[nctinter]

I'm no engineer but this looks like more than enough support.

 

[dave.m]

Hire a structural engineer. He will tell you how to do it right and sign off on it. This is important as your insurance company will take you to town if there is ever a problem and you don't have that signature.

Dave.M

 

[sleepydoc]

+1
Think about what you're doing - You're putting a tank that will weigh over a ton. You're concerned about the structural integrity of your floor and trying to reinforce it but not sure if you're doing it correctly. So you ask a bunch of people you don't know, with who-knows-what credentials training and experience, and under absolutely no obligation to be right.

Having a professional look at it seems to be an easy choice to me

 

[BlackTip]

I appreciate all the responses so far.

Hiring a structural engineer was the obvious choice, but I found it to be very costly and overkill. An engineer will not sign off on anything without proper planning and documentations. House plan, floor blueprint, joists specifications, soil analysis, jacks specification, etc. This process will easily cost close to 2K. Where I live, an engineer demand $650 just to start talking with me. Overkill, IMHO.

I don't need a permit from the City, because it is considered non-permanent structure. So, I don't see any reason for a problem with an insurance company. I am not removing any existing structure. I am adding to it. I don't see what could possibly go wrong?

I have a retired friend who used to do this kind of stuff for living, and he educated and guided me through the design.

The reason I posted this here is because I am sure many reefers had the same issue to solve. I was looking for tips, anything I missed, etc.

 

[sleepydoc]

Understand your thoughts, but the usefulness of any advice you get here is of limited value for the same reason the engineer requires plans, specs, etc. All those things matter and can significantly impact the integrity of your structure/solution. Something that's adequate for one application may not be for another.

Not requiring a permit does not automatically mean there will be no insurance issues if there is a problem. Regardless, the insurance should be a secondary concern. I'd rather not need to use my insurance in the first place!

It sounds like your friend may be your best resource for this - he has experience, he can actually look at your house, and he's your friend

 

[SeargentSlice]

You know you don't want treated lumber in your house rite? Second I would have used untreated solid 6/6 for your beams. Your 6/6 are ok but you could have sandwiched plywood between them with liquid nail and screw it together. Plywood on edge is way stronger than milled lumber hence the construction of your existing joist. Plus you added more floor joist already between existing to bearing points. That alone will hold the tank but good call on Cross support beams and jacks as well I think you got her done. For what you are doing you don't need an structural engineer lol. And on a side note being in commercial construction for 15yrs Architects and Engineers make there fair share of mistakes and are constantly making revisions to the blueprints as the structure takes form.

 

[BlackTip]

Thank you for your response.

Could you please tell me why I don't want treated lumber in my crawl space?

You know you don't want treated lumber in your house rite? Second I would have used untreated solid 6/6 for your beams. Your 6/6 are ok but you could have sandwiched plywood between them with liquid nail and screw it together. Plywood on edge is way stronger than milled lumber hence the construction of your existing joist. Plus you added more floor joist already between existing to bearing points. That alone will hold the tank but good call on Cross support beams and jacks as well I think you got her done.

 

[SeargentSlice]

Thank you for your response.

Could you please tell me why I don't want treated lumber in my crawl space?

Treated lumber is toxic supposedly they changed the chemicals used to treat the wood to make it safer after 2003 lol yeah rite.
I only would use it outdoors or in well ventilated areas that are not subject to the air in my home . I have alot of carpenter friends in the trades that are experiencing health issues from cutting , handling and breathing fumes from treated lumber.

 

[BlackTip]

^^^
Thanks for the explanation.

 

[SeargentSlice]

^^^
Thanks for the explanation.

Just google it and you will find plenty of info. If your crawlspace is not subject to the air in your home then maybe no concern for you.

 

[sleepydoc]

In many cities (including mine) baseplates at grade are required to be treated.

Treated lumber is by definition toxic. The whole point of the treatment is to make it toxic to the organisms that can cause rot and decay. These substances are also toxic to humans, which is why it is advised to wear a respirator when cutting treated lumber so you don't inhale the dust.

Working in an environment where there is dust from freshly treated lumber is very different from having a board of treated lumber in your house. If it's in an area where the board may be susceptible to rot, I would use treated lumber. Otherwise you risk your support becoming unstable with time.

 

[SeargentSlice]

In many cities (including mine) baseplates at grade are required to be treated.

Treated lumber is by definition toxic. The whole point of the treatment is to make it toxic to the organisms that can cause rot and decay. These substances are also toxic to humans, which is why it is advised to wear a respirator when cutting treated lumber so you don't inhale the dust.

Working in an environment where there is dust from freshly treated lumber is very different from having a board of treated lumber in your house. If it's in an area where the board may be susceptible to rot, I would use treated lumber. Otherwise you risk your support becoming unstable with time.

Lol my house was built in 1920 and built with 100% hardwood material and I don't have any rotted wood! And I gurantee it stands for another 100yrs! Sry baseplates are pretty much sealed off from air circulation and ik its code don't mean its good. I didn't say treated lumber in your house was bad cuz i felt like It! You can make that call on your own I was just sayin I know people suffering from it Im not one to get into ****ing matches but McDonalds claims its a healthy meal good day sir.