Civ-E question

[~Flighty~]

How strong is a cinder block wall?

I want to build a cistern in the basement and am wondering if a simple cinder block and mortar wall will suffice. The wall will be L shaped an span 4 and 8 feet. It will be six courses (4ft) high. The water won't normally go to the top, but it has to be strong enough in case it somehow overflows to that depth. That's 1.76 PSI at the bottom I think.

Will I have to tie it to the foundation or floor? Would I need to re-bar reinforce it? If it wouldn't be strong enough would increasing the thickness at the bottom fix it? Can I somehow use flying buttresses? I like flying buttresses

 

[Matt L.]

I am a liscenced Civil Engineer (well, almost -- I just have to get the money together to pay for it), but I think this is more of a question for a contractor.

It seems like it should be okay, but I am not sure of any code issues. Yes, the wayer at the bottom will be about 1.8 psi. The overall force acting over the 4x8 wall would be about 4000+ pounds, or 125 pounds per square foot. The overall force acting over the 4x4 wall would be half (2000+ pounds), but have the same force of 125 pounds per square foot.

With those forces, if the wall isn't tied down to the basement floor, I could imagine that there could be some cracking or separation even if the cinder blocks are all cemented and properly restrained with rebar internally.

Matt

 

[Jim Tansey]

Cindy I think you need to build a saltwater pool and you can get some use out of it.

Jim

 

[~Flighty~]

No thanks, you may want to revisit the thread about Piscevore's lip.

 

[maurod]

No thanks, you may want to revisit the thread about Piscevore's lip.

I still think he made out with a frogfish.

M.

 

[delta]

i wouldnt recomend it and with all you need to do i think the steel frame would be cheaper all said and done.
i think you are going to have too many structural issues to over come here.
cinderblocks are not designed to take a load from the side let alone one side and not the other. filling the wall completely with high PSI concrete along with steel reinforcment from the walls and floor is a must but by the time you are done you might as well have a steel frame welded up and put plywood on the inside then use your'e pond liner.

HTH

 

[~Flighty~]

i wouldnt recomend it and with all you need to do i think the steel frame would be cheaper all said and done.
i think you are going to have too many structural issues to over come here.
cinderblocks are not designed to take a load from the side let alone one side and not the other. filling the wall completely with high PSI concrete along with steel reinforcment from the walls and floor is a must but by the time you are done you might as well have a steel frame welded up and put plywood on the inside then use your'e pond liner.

HTH

I think you're right, but I don't have to like it.

Anyone have the specs on how much force a cinderblock wall can take to back it up? Or how deep could I go with cinderblock? 3 courses? 4?

 

[NateHanson]

I really don't have any educated input to contribute, but my gut agrees with greg on this on.

Nate

 

[~Flighty~]

I really don't have any educated input to contribute, but my gut agrees with Greg on this on.

Nate

Oh ya? well all of you are poopheads. That's what I think. I'm going to hold out for a fourth opinion.

 

[NateHanson]

Maybe the fourth will have a clue as to what they're talking about.

 

[~Flighty~]

Doesn't Denis do something like this for work or am I remembering that wrong? Maybe he knows how to tell a girl what she wants to hear

 

[Matt L.]

Cindy, why not use a bathtub or a hot tub shell? Those are designed to hold that kind of weight. Plus, they are already plumbed and should have a surface easy to clean. A bathtub has got to hold 40gal, right?

Matt

 

[~Flighty~]

Looking for 600+ gallons and it has to fit through a 38" door. That's a lota bathtubs. Looks like I may go plywood, but that is so less sexy than masonry.

 

[NateHanson]

If you want "sexy" go for the hot tub.

I'll bet it would be cheaper and certainly easier to stack two 300g rubbermaid stock tanks. You could have a very simple metal stand made to stack the tanks.

Nate

 

[Mini4x]

Thats one hell of a sump design!!

 

[KAS]

If you want "sexy" go for the hot tub.

I'll bet it would be cheaper and certainly easier to stack two 300g rubbermaid stock tanks. You could have a very simple metal stand made to stack the tanks.

Nate

My hot tub is 500 gals and has an easily removable insulated cover.

I don't think I can turn the heat down below 90 though.

 

[NateHanson]

Maybe we'd better come do a little research into that technology Karen.

 

[~Flighty~]

LOL We have a 6 person hot tub. It even has a uv sterilizer built in. Only problem is it is like 50 feet away from the sump. Now, putting a big display tank in the hottub room... Hmm, how would I keep the condensation off of the glass? ...

 

[dedfish]

I have no clue what I'm talking about but I think Cindy just really really really wants to build a wall out of cinder blocks no matter how much work it is.

 

[MarkO]

Concrete is great in compression, but has very limited tensile strength.
Do the kids know how to swim?