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Discussion Starter #1
Hi all. As an early step in my basement finishing project, I had a plumber rough in a powder room. He dug the trench and tied into the sewer line and buried the pipes, but did not lay any new concrete (we agreed to this prior to the work being done).

So I'm just curious, what is the best way to patch up the slab where the trench was dug? Is there a specific kind of concrete or mortar that is best for this application? Do I need to add any crushed stone or anything, or can I just lay my concrete right on top of the soil? My 1926 house has a 3"-ish slab.

I should add that once I have things patched up, I will be leveling the floor with a self leveling compound. For this reason, the patching doesn't need to be perfect. God damn I can't wait for that floor to be smooth. It's a mess!
 

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Do I need to add any crushed stone or anything, or can I just lay my concrete right on top of the soil? My 1926 house has a 3"-ish slab.
Ayuh,.... If yer lookin' at a 3" deep trench now, I'd just go buy enough bags of plain ole bagged concrete mix, 'n start mixin', 'n pourin',....

It's only gotta support yer weight, 'n if the rest of the slab is sittin' on dirt, yer patch won't care whether there's stone under it or not,....
The only reason to add stone is so ya don't haveta mix as much concrete to fill the hole,...

Level, 'n smooth it as close as ya wish, let it set a few days, 'n do yer levelin' compound thing,...
 

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Tamp the dirt down as much as you can. Use a 4x4 or something similar. Then fill the hole even with the bottom of the existing slab and fill the rest with concrete mix. Do not use mortar mix. It is too soft.
 

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Discussion Starter #5
Hi all, thanks for the responses. I picked up a few bags of Quikrete High Strength Concrete Mix and plan on patching everything up this weekend. It sounds like I don't need to fuss with crushed stone since I'm working with a 3" slab that is sitting on top of dirt.

Attached is a photo of the trench. On the left is a french drain that is being repaired once the plumbers are done working today. Once the waterproofing people repair the french drain, I'll be all set to level my floor. Can. Not. Wait!

 

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I've no idea what was done in the compaction department before the drain was laid, but that's important to maintain the slope required by code.
 

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Remodel and New Build GC
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Oh Boy.... getting that finished will be great.....:smile:

Sometimes in new build/addition.... I think the best part of the job is getting the slab poured and getting out of dirt.....
 

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You have a job ahead of you, get the rest of the broken concrete out on the left side of the pic, then compact the dirt to the 3" point of your slab, and be sure you put a bulk head in when you stop pouring for the day, unless you have a lot of help and can finish it in one day.
 

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Do you have some code requiring cast iron. Why wouldn't they have replaced that cast with new PVC while the hole was open?
 

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Naildriver
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I'm confused. Is that dirt in the trench? No concrete? Maybe I missed something. We usually put water in our concrete mix.
 

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Remodel and New Build GC
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I'm confused. Is that dirt in the trench? No concrete? Maybe I missed something. We usually put water in our concrete mix.
Rationing restrictions....????

But I like the custom color of the concrete... should look nice under the floor covering.
 
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