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Footing Problems - Forno Bravo Forum: The Wood-Fired Oven Community


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Footing Problems

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  • Footing Problems

    I dug 32" deep trenches for my footings, placed a drain pipe around the perimeter, then covered the bottom with a couple of inches of gravel for drainage. Before pouring the concrete for the footings I tied the vertical pieces of rebar to the horizontal rebar, hoping they would line up with the cinder block cores better than if I were to place them in the wet concrete. So far, so good...

    I ordered enough concrete for 10" footers, but the mixing yard gave me more than I needed and the footers are a little over 12" deep. By the time I got the last of the concrete into the trenches it was drying out and I wasn't able to work it to get it level. The best I could do was shoot for close to level.

    I am now placing cinder blocks on the footers and am running into some problems. First, my footings are not as level as I had hoped they would be. For the time being I'm just placing shims under the cinder blocks to get them closer to level. I figure I can then use cement or mortar to make a bed for the first course to rest on to get level.

    Second, some of the rebar doesn't line up perfectly with the cinder block cores. Some are off by about 1" and come up where the cinder sits (not into the core). I've tried to bend the rebar a little and even chipped out notches in the blocks to get the rebar into the core.

    Right now the best I can get is fairly close to level from corner to corner (still off by maybe 1/4").

    With the rebar touching the base of a few of the cinder blocks, I am not getting my blocks to line up perfectly straight and square. Some blocks are shifted a bit out of alignment with the rest of the course, and some are shifted forward, creating a gap between the blocks (about a 1" gap in two places). This is throwing whole base out of square.

    So, here are my questions...

    1. Should I use concrete or mortar (or some other way) to get the first course level?

    2. Is it going to be a problem for me if the cinder blocks are not in a perfectly straight line and not exactly square? The cores still line up enough that I can fill every other one with concrete. I'm setting only two courses of blocks and will then pour a slab on top. Will this affect the support under the slab if they aren't straight and squareunderneath it?

    3. Will the 1" gaps between some of the cinder blocks be a problem? The shift puts it out of square but with the rebar that's the closest I can get. Should I fill the gaps with concrete then put some vapor barrier around the base to keep out water?

    Basically, how close to perfect (straight and square) does my base have to be to support the slab that will be poured on top?

    I appreciate any help or input anyone may have.

  • #2
    Re: Footing Problems

    Once your footing concrete sets up in 3 or 4 days, you can bend the rebar and "zig zag" it into the block openings.

    As to being perfectly level, if it is not apparent to the eye don't worry about it. Some people even suggest that the structural slab (and hearth) should be slightly sloped by 1 to 2% to facilitate drainage should water get in.