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Filling the hole left by my chimney

kvng | Posted in General Questions on

I just finished removing the last brick of my chimney and now I’m left with a bit of a dilemma: I didn’t plan how to fill the void in the garage floor where the chimney had been sitting.

I got stamped drawings for the crawlspace opening I plan to make in the void left in the stem wall, but I’m unsure about how to form the concrete base and handle “flashing” the crawlspace liner around the opening. I drew up my naive solution to how I could handle it, but I knew you guys would let me know if I was doing something silly.

Edit: also included an image of a sunken entryway that might be easier to implement.

Also, is rebar a bad idea in this case? The portions of my foundation where rebar was used appear to be experiencing spalling/efflorescence due to the wet nature of the soils around here.

Should I put some kind of capillary break under any pour I do, or is that counterproductive because it’s on top of the chimney footing?

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  1. PAUL KUENN | | #1

    So it sounds like you are going to put an access hatch there, correct? As you have soil exposed, I would dig out a bit more under the slab so you can add some 3/4" gravel without fines around the perimeter as a capillary break before the pour. If that pad in front of the access will be less than 4" of concrete, I would add a bit of rebar or fencing.

    1. kvng | | #2

      Sounds good; I think I'll pour it flush and lay down 2 inches of 3/4" gravel across the whole thing, as I'll still have enough room for the opening to meet code even if it's flush all the way.

      The crawlspace was semi-encapsulated by a previous owner, so I'm planning to stash infrequently used items down there. That said, I can't think of a good reason for needing an enormous opening.

      Would you recommend doweling rebar into the existing slab at all? Using any sort of treatments to help with bonding or drying?

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