Floor bracing ?

[B_IN_SD]

I have a summer project that I need to start working on. There is a crawl space under my house and I need to brace the floor to hold a large plywood tank. The tank will be 8' wide 7' front to back and 3' deep. that is 1000 gallons and 8600 lbs of water weight at 80% full so how ever the floor is braced it needs to be rock solid.

This is where I need the help. I really dont have a clue on how or what to use to brace the floor. Can I pour concrete pileings or something simular to make the foundation for the tank. the crawl space under the tank room is about 2' and I can pull up the flooring to work on the bracing and I can supply pics of anything needed.

I have tried another construction forum for answers but all i get is find an engineer. This has got to be easy enough that I can get er done without an engineer and will more than likely be way overbuilt for my peace of mind.

 

[Johnnylightning]

No offense if you can't afford professional work don't try for a monster tank. Insurance companies won't pay for stupidity.

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[james_unknown]

Or you could ask them to come out and give there professional opinion and what they would need to do it so you have an idea of what you need and what you would need to do but that might cost some money to


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[skjl47]

Hello; The suggestion to get the opinion of an engineer is sound and likely the best option. That said, as long as you are willing to take a big risk there are ways to brace a floor on your own. The potential issue(s) lie in not having the knowledge to recognize problems in the ground and/or the structure of the house.
A young friend is a geotechnical engineer and we have talked over time about the things he was learning in school and lately work site experience since he has taken a position in the field. Over the weekend he described a techinque for testing the strength of soil in order to determine how much and what type of footing to use. Without that kind of knowledge or experience you could make an error in pouring a footer. A general contractor might be a good second path to some advice on how to proceede.
If you go ahead on your own there are likely codes for footers that are published and likely will get you close to what you need. My guess is that SD is far enough north to require a footer to be poured below the frost line. Instructions for decks may help.
I have seen the type of piers you mentioned under houses many times. If you do take up the floor it will make digging the holes much easier. Once holes are dug cylinders are available to place in the holes into which you can add the cement and a metal bracket can be set on top of the wet cement that is made to accept a 4x4 post. Under a floor you will likely want to use pressure treated wood.
The floor joists can be strengethened by sistering additional joists onto them and by boxing in between the joists.
Metal jacks can be used in place of wood posts. I think they may be call a lolly post.
On the redneck end of the spectrum I have seen two by ten boards laid on the ground with cement blocks stacked on them and more boards on top of the cinder blocks to shim up a floor. Sometimes without any mortar at all.
It all depends on how secure you want to be and how much you worry about things.

 

[815billybob]

I have a crawl space also. I brace my floor for all of my tanks all you need to do is go to manards and get floor jacks and a couple 4x4s and some blocks for the jacks to sit on and put the 4x4s across your floor Joice and tightin your jacks it not a big deal as long as your not afraid of spiders lol. The jacks cost around 20 bucks

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[Totroc3]

I just set up a 475 gallon ray tank with a 90 gallon wet dry. I also had fears of the floor falling through. I called a handyman crew to come out and they had done this several times for others. They brought in 13 concrete piers and placed them on 2x8 boards for addition support on the ground. They then ran 4x4 posts up and attached them to the existing supports which were 4x12. They felt it would be fine without the additional supports but I needed to feel secure and had them do it anyway. Total cost was about 500. It was well worth it just for the peace of mind. Hope this helps you. Good luck with the tank.


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[snowhnter]

AT YOUR OWN RISK, Proceed how you think is best but this is how I would do it and I have set many moblie homes weighing much more than your tank will.
Assuming your floor joists are set on 16" centers you tank will span 7-8 joists. Under each joist dig a hole 2'x2' deep enough to hit hard soil (assuming you don't have access to GPR or sounding equip), or you can dig an strip 2' wide long enough to cover the joists you will span. Dig these holes at both ends of the tank and at the 2.5' mark and 5' mark. When you finish digging you will have 32 holes or 4 strips. In these holes pour in enough concrete to make a 6" pad, MAKE SURE THE PAD IS LEVEL. On each of these pads set 2-8" limestone blocks side by side, set 2 more blocks on top turned 90 degrees to the first 2, and keep repeating till you are within 6"-7" of the joists. On top of your piers place 2-4"solid limestone blocks following the pattern, the solid blocks keep mice and rats from nesting. On top of the solids place 2-oak or poplar headers. This should bring you very close to the joists. Use 2 wooden wedges on each block, coming in at opposite sides of the joists to tighten the piers to the joist. Done correctly floor can't sag.

 

[B_IN_SD]

No offense if you can't afford professional work don't try for a monster tank. Insurance companies won't pay for stupidity.

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I can afford it but I am also willing to do the work. there is no reason to pay someone to do what you can do. no offense taken.

Or you could ask them to come out and give there professional opinion and what they would need to do it so you have an idea of what you need and what you would need to do but that might cost some money to

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Thanks I will look into that.

Hello; The suggestion to get the opinion of an engineer is sound and likely the best option. That said, as long as you are willing to take a big risk there are ways to brace a floor on your own. The potential issue(s) lie in not having the knowledge to recognize problems in the ground and/or the structure of the house.
A young friend is a geotechnical engineer and we have talked over time about the things he was learning in school and lately work site experience since he has taken a position in the field. Over the weekend he described a techinque for testing the strength of soil in order to determine how much and what type of footing to use. Without that kind of knowledge or experience you could make an error in pouring a footer. A general contractor might be a good second path to some advice on how to proceede.
If you go ahead on your own there are likely codes for footers that are published and likely will get you close to what you need. My guess is that SD is far enough north to require a footer to be poured below the frost line. Instructions for decks may help.
I have seen the type of piers you mentioned under houses many times. If you do take up the floor it will make digging the holes much easier. Once holes are dug cylinders are available to place in the holes into which you can add the cement and a metal bracket can be set on top of the wet cement that is made to accept a 4x4 post. Under a floor you will likely want to use pressure treated wood.
The floor joists can be strengethened by sistering additional joists onto them and by boxing in between the joists.
Metal jacks can be used in place of wood posts. I think they may be call a lolly post.
On the redneck end of the spectrum I have seen two by ten boards laid on the ground with cement blocks stacked on them and more boards on top of the cinder blocks to shim up a floor. Sometimes without any mortar at all.
It all depends on how secure you want to be and how much you worry about things.

Thanks, I have a contractor friend I will ask what he thinks. I need to be absolutly certain this will hold and for a long time ! Blowing the floor out is really not an option. The blocks and lumber method is how my 360 is being held up and works as expected BUT this build is bigger and heavyer and will be in place for a long while so it needs to be done correctly. I work at a mine and there is an engineer i can ask about soil compaction.

I have a crawl space also. I brace my floor for all of my tanks all you need to do is go to manards and get floor jacks and a couple 4x4s and some blocks for the jacks to sit on and put the 4x4s across your floor Joice and tightin your jacks it not a big deal as long as your not afraid of spiders lol. The jacks cost around 20 bucks


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That is what I originally had planned on doing BUT the more in depth I get on this I am thinking I really need to be to code + some. my house was built in 1924 it would be ashame to collaps half if not more of the house after that many years. Thanks

I just set up a 475 gallon ray tank with a 90 gallon wet dry. I also had fears of the floor falling through. I called a handyman crew to come out and they had done this several times for others. They brought in 13 concrete piers and placed them on 2x8 boards for addition support on the ground. They then ran 4x4 posts up and attached them to the existing supports which were 4x12. They felt it would be fine without the additional supports but I needed to feel secure and had them do it anyway. Total cost was about 500. It was well worth it just for the peace of mind. Hope this helps you. Good luck with the tank.

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Thanks

 

[B_IN_SD]

AT YOUR OWN RISK, Proceed how you think is best but this is how I would do it and I have set many moblie homes weighing much more than your tank will.
Assuming your floor joists are set on 16" centers you tank will span 7-8 joists. Under each joist dig a hole 2'x2' deep enough to hit hard soil (assuming you don't have access to GPR or sounding equip), or you can dig an strip 2' wide long enough to cover the joists you will span. Dig these holes at both ends of the tank and at the 2.5' mark and 5' mark. When you finish digging you will have 32 holes or 4 strips. In these holes pour in enough concrete to make a 6" pad, MAKE SURE THE PAD IS LEVEL. On each of these pads set 2-8" limestone blocks side by side, set 2 more blocks on top turned 90 degrees to the first 2, and keep repeating till you are within 6"-7" of the joists. On top of your piers place 2-4"solid limestone blocks following the pattern, the solid blocks keep mice and rats from nesting. On top of the solids place 2-oak or poplar headers. This should bring you very close to the joists. Use 2 wooden wedges on each block, coming in at opposite sides of the joists to tighten the piers to the joist. Done correctly floor can't sag.

Thanks Snowhunter I will ask about this and it is very simular to how I braced my floor for the 360.