Shoring up a floor

in_the_tank · 04-23-2012, 03:51 PM

Hello everyone ! 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 aquarium. The aquarium 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.

Where should I start ?

CplDevilDog · 04-23-2012, 04:00 PM

An Engineer

You're essentially putting a Hot Tub in your living room. I wouldn't guess on something like that. If you're wrong the structural damage and risk to life would be severe.

Have you done something like this before? I suspect arrangements would have to be made for venting the extra humidity to the outside.

cortell · 04-23-2012, 04:25 PM

You're talking about 3-4x the load a normal residential floor is designed to bear. You should indeed talk to an engineer. My guess is you'd need to pour a rebar reinforced concrete pad, or a number of oversized footings and frame like crazy above it, probably using engineered beams and joists (or use concrete blocks). If you're lucky, you live where there is no frost line (or not much of one); otherwise you might be looking at some serious digging...all of which has to happen by hand.

danpik · 04-23-2012, 04:26 PM

Definatly get an engineer. He will need to look at the structure under the floor (most likely 2x8/10 framing on 16" centers) to see what to recomend for structure under it. I would suspect there will be some digging to install a footing of some sort.

in_the_tank · 04-23-2012, 04:36 PM

Quote:

Originally Posted by CplDevilDog

An Engineer

You're essentially putting a Hot Tub in your living room. I wouldn't guess on something like that. If you're wrong the structural damage and risk to life would be severe.

Have you done something like this before? I suspect arrangements would have to be made for venting the extra humidity to the outside.

At least a hot tub if not 2 or 3 in weight. You are correct if it caves the floor in the house is giong to be in rough shape. No I have never braced a floor with anything other than cinder blocks. I will not use blocks for this project, it needs to be rock solid and lasting 20+ years. All the tank details are figured out along with venting and elect.

in_the_tank · 04-23-2012, 04:42 PM

Quote:

Originally Posted by cortell

You're talking about 3-4x the load a normal residential floor is designed to bear. You should indeed talk to an engineer. My guess is you'd need to pour a rebar reinforced concrete pad, or a number of oversized footings and frame like crazy above it, probably using engineered beams and joists (or use concrete blocks). If you're lucky, you live where there is no frost line (or not much of one); otherwise you might be looking at some serious digging...all of which has to happen by hand.

I am in western South dakota there is a frost line

cortell · 04-23-2012, 04:45 PM

Quote:

Originally Posted by in_the_tank

I will not use blocks for this project, it needs to be rock solid and lasting 20+ years.

Concrete blocks are plenty strong. More US homes are held up with concrete block foundations than poured concrete foundation walls. When built correctly--with vertical rebar and horizontal bond beams--they can hold up just about anything. They should rest on a poured concrete footing, though.

Ravenworks · 04-23-2012, 05:40 PM

You could ask your eng about spread footings and bridge across them supporting the existing joist.

in_the_tank · 04-23-2012, 06:45 PM

Any engineers on here want to take a stab at this ?

AndyGump · 04-23-2012, 10:33 PM

How about hiring an engineer rather than asking for a free design?

They need to eat too.

Andy.

in_the_tank · 04-23-2012, 10:46 PM

Quote:

Originally Posted by AndyGump

How about hiring an engineer rather than asking for a free design?

They need to eat too.

Andy.

yes they do, but so do I. isn't this a diy forum ?

AndyGump · 04-23-2012, 10:56 PM

What you are asking for is way outside IRC or any prescriptive practices.
Yours is a project that could very well involve life safety issues.

Even if you wanted to get his permitted to be compliant and safe your Building department will probably want engineering on this. Not something designed by knuckleheads that have never visited, seen or taken one measurement of your house from a DIY talk forum.

Sorry, I am sounding a bit nasty, I will stop.

Andy.

cortell · 04-23-2012, 11:00 PM

Quote:

Originally Posted by in_the_tank

yes they do, but so do I. isn't this a diy forum ?

It's for getting advice on specific questions or general questions. It's not a site where you describe what you want to accomplish and someone crunches the numbers for you--be it materials list, costs or structural specs. Expect ideas, not specifics.

CplDevilDog · 04-23-2012, 11:09 PM

I think what Andy meant to say is, we get a lot of questions here asking for Engineering design.

We like answering DIY questions but there are so many things to consider with a project like this that we don't feel comfortable offering off-the-cuff solutions.

What are the soil conditions in your crawl space?
Is there currently a slab poured in the crawl space?
How far away from your exterior foundation are you going to be?
Since you'll probably want to pump the concrete, an Engineer would be able to design a proper mix for you.

See how quickly things get complicated?

Try calling around, often you can find a local Engineer that can work with a homeowner for a very reasonable fee. An ounce of prevention is worth about 8000 pounds of cure in this case.

in_the_tank · 04-24-2012, 12:25 AM

Quote:

Originally Posted by CplDevilDog

I think what Andy meant to say is, we get a lot of questions here asking for Engineering design.

We like answering DIY questions but there are so many things to consider with a project like this that we don't feel comfortable offering off-the-cuff solutions.

What are the soil conditions in your crawl space?..........dry since 1924
Is there currently a slab poured in the crawl space?.......no
How far away from your exterior foundation are you going to be? 1' at the closest.
Since you'll probably want to pump the concrete, an Engineer would be able to design a proper mix for you.......... There is no way to pump ready mix into this space, 5gl buckets are about the only way.The space is a bedroom with 2 small windows.

See how quickly things get complicated?........Yes I do but this cant be that complicated. It's basicly just a fishtank stand.

Try calling around, often you can find a local Engineer that can work with a homeowner for a very reasonable fee. An ounce of prevention is worth about 8000 pounds of cure in this case.

........I hear you but there has got to be a good way to diy this without calling out the national guard.