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I need to make sure my concrete slab is flat and level (with slight fall for water runoff).

I have some spare bricks. I was thinking I could set some of these bricks into the slab as I pour it and use them as my height gauge. Is that an ok thing to do, or will the bricks absorb water and break up or anything like that?

EDIT: This is because I can't put an edger/form along two of the sides due to an existing wall.

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  • How large a slab? Runoff angle was set when floating to a level surface, guided by a few boards around the slab's edges, in my limited experience of pouring shower house floors. If you really need references in the middle of the slab, I'd just plant a few sticks, mark the desired height on them, and pull them after they have served their purpose, rather than leaving something embedded in the slab ..
    – keshlam
    Commented Sep 22, 2023 at 16:18
  • Tapcon a 2x4 to the wall. Screw a 2x4 short on top of your 2x4 screed board, sticking out ~2". The short rides on top of the one attached to the wall. But you only get to jiggle it less than 1.5".... diy.stackexchange.com/a/183937/23295
    – Mazura
    Commented Sep 28, 2023 at 4:02

1 Answer 1

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Just do what every concrete job normally does and set screed guides (usually the tops of the forms - takes a fairly huge job to required intermediate ones, which are fussy and annoying because you have to screed the concrete and then pull them at the right point that the hole they leave can be filled, but the surface around them does not slump when they are pulled. Easy enough for pros, difficult to judge right for amateurs.)

If your slab is huge, pour it in sections so you can screed with the top of the forms. Bricks will at minimum be a weak spot in a concrete slab, and don't really make a good screed guide.

You have edited to update that you are pouring against a wall on two sides. Do your walls and your slab a favor and use expansion joint material between the two, and set the top of the expansion joint material at the correct level/slope to guide your screeding.

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  • And if you can't use a piece of expansion joint, at least paint yourself a line on the wall you're pouring up against!
    – Huesmann
    Commented Sep 23, 2023 at 13:19

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