how much weight can a concrete foundation handle?

[BBQHILLBILLY]

how much weight can a concrete foundation handle?

Im thinking of purchasing a 300 gallon tank. Thats 8lbs per 300 gallon for 2400lbs of water.

When does the concrete foundation begin to have a problem?

Thanks

[randomfish]

if your slab is 6 to 8" you should be fine

[justahobby]

Not to mention the tank itself which probably weighs several hundred pounds, plus stand, live rock, sand, sump w/ water, rock, etc. Are you planning to put it on bare concrete? Might want to find kkiel's build thread and see if he addresses that issue. I remember his tank being in the 300g range.

[Gseclipse02]

my buddy has a 300G his house that side with the tank is now 3 inchs lower in 6 months or so

[Texreefer]

all depends how it is reinforced, if its near an outside wall and if its got a solid base under it.. the load is spread over a large area of concrete.. and the concrete itself has 1500-2400 lbs/in"2 of crush strength.. unless its an old house on soft soil, i say you have Zero to worry about

[tiger_eyed1]

Let’s put it in perspective. Would you be worried about having 15 200lb people or 11 mastards stand where the tank would be? You will be fine.

[hobogato]

i love the conversion factor of 15 normal people = 11 mastards :lauging:

[alton]

i love the conversion factor of 15 normal people = 11 mastards :lauging:

Hey hey this is getting personel

Here are some comparisons

Your 9000 lb ford 350 sits on top of your driveway that is 3.5" thick and only contains wire mesh, usually no rebar. And that comes out to 2,250 lbs per square foot.
A 4 x 4 pallet of carpet grass wet is like 4,000 lbs

If you have a brick wall and it is 8' long x 9' tall with morter you are looking at something like 3,300 lbs

[BBQHILLBILLY]

this is great information and perspectives. So does it matter to place a 300 gallon tank parallel or perpendicular to rebar and

Why would someones foundation get a pitch of 4 inches as stated earlier? maybe because it was hollow under foundation?

Lastly would the weight distribute through a larger area if 2x8 wood/plywood be placed under the stand? safer?

great info by the way and thanks

[rrasco]

It's not uncommon for foundations to move in this region due to the soil drying out and re-hydrating, over and over.

[alton]

In my slab the rebar was laid on 12" or 18" centers running vertical and horizontal, the main beams where 24" deep. I have seen beams 3' deep..
Some contractors in San Antonio do not use rebar, they use cables to hold the slab together. I do not think this is a trade secret but a large retail store does not have any steel in there slabs. They put steel in there outside beams and of course in the concrete holding up the columns.

The more you spread out the weight the less pressure on the slab.

[grouch]

Be thankful your in SA not DFW. The foundations in DFW have steel tesion cables through them and rebar. The steel cables are there to hold the foundation together if it cracks due to earth movement. The builder of my house in Keller have to come back for several homes including mine and pier the foundation which is jacking your house up to level and driving steel piers all the way down to bedrock under the foundation, this was 35ft. in my case. In SA especially on the north side there is so much rock so close to the surface I don't think the foundations are going to move nearly as much. I'm sure there are areas with foundation problems here as I have seen foundation repair companies in buisness. The clay soil in DFW can contract 5x the size in relation to soil moisure content but as I have noticed there is not much topsoil here and if your house is on rock it doesn't move much.

[rrasco]

Oh, they move here. There are lots of foundation repair companies around here and it's not cheap. My foundation needs to be fixed (pier reinforcement), my dad has had his fixed, and I know several others who have had repairs. This summer has been especially difficult due to the drought, as the soil dries out, it compacts and the foundation settles, often causing damage to the house, although, mostly cosmetic. Cracked/lifting tiles, cracks in drywall and ceiling, doors sticking/not closing, etc. That's why they say to water around your foundation with a soaker hose, it get's difficult though when it's as dry as it was this year.