Can I pour my concrete over this rock bed after the rough in?


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Old 03-03-11, 05:37 PM
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Can I pour my concrete over this rock bed after the rough in?

Ok so to make a one year long story, very very VERY short...

-4x7 powder room needs to be a full bath but the gas meter is mounted indoors!
-gas meter moved outside to make room for shower
-concrete basement floor holds existing rough in for toilet only
-demo'd the concrete floor (4")
-dug down to reveal existing cast iron piping
-plumber comes to replace existing cast iron with PVC and rough in the shower drain (I just didn't feel up to it)

Our neighborhood has an extremely high water table. to give you an idea, my sump pit (although I just adjusted the level to less than the height of the sub drainage system) has a happy level of about 14" - 16".

Because of this, it made for an interesting dig down under the bathroom floor. once I got about 5 inches below the concrete, I found water. I mean, I FOUND water. meaning, standing water. This made it really hard to install the new drain pipes, we had to constantly bail the water out so he wasn't setting the glue on the pipes in water.

Anyhow, the inspector came out and passed the rough in. now it was time for me to fill the floor back in. I filled it in with the rock/clay (mostly little rocks though) that I dug out of it. anyhow, when I began back-filling there was about 4" of standing water. I continued to back fill until I had used all of the material which came out of there.

Once I was done, I noted that several spots (but mainly just in the center of the tiny room) were squishy. I mean, water bed squishy. so I went to home depot and bought some bags of rocks which I dumped in and stomped down. marked improvement however, it's still a bit "really really firm, water bed squishy".

because I know squishy is a relative term and it would be difficult for any of you to know the magnitude of this particular squishyness I speak of, I've made a short video starring my wife, the squishy bathroom rock floor adventurer. Hopefully this will illustrate what I mean.

QUESTION: can I really pour concrete on top of this in it's present condition? the outer edges of the room are pretty solid, it just seems to be the center part where the new brownish rocks are.

http://s797.photobucket.com/albums/yy251/moveright/?action=view&current=MVI_3178.mp4
 
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Old 03-04-11, 06:03 PM
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The good news is, your wife is a born star. The bad news is, the cement won't hold. At least I don't think it will. I would remove the stone & try to frame something that will hold the stone in place. Then you can pour whatever you want.
 
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Old 03-04-11, 07:41 PM
Tolyn Ironhand's Avatar
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IF your pouring 4" (3 1/2") of concrete Id say your fine. The concrete will hold itself. IF your worried add some rebar.
 
 

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