24” long for the slab frame

Good Morning,
Is it necessary for the wood stakes to be 24” long for the slab frame? The ground that I am working with is very hard, and I fear they will break off before I reach the 3” – 4” off the ground. Thank you for any advice.
I‘m located in Southern California.

Hello, Lia!

24 inches is ideal. The idea is to anchor most of the stake in the ground because you are pouring a lot of mass into the form, and the pressure outward on the forms can easily uproot a stake.

It sounds like it must have been quite a slog to dig the “footprint” for your slab as well.

Rather than simply pounding them in, here’s a couple of ideas:

  • If you have a “breaker bar” (which is simply a long steel rod with a point that is very heavy and is typically used to break up rocks and stones while digging), you could try using that to open a “pilot hole” for your stakes. That way you’re not depending on the stake to open up the space.
  • You could also use a shovel to break up the soil where each stake goes, then use your concrete tamper around the stake to compress the soil again. If you were in a shallow hole it wouldn’t work very well, but the depth should secure the stake well enough for what you need.

However you do it, I encourage you to find a way to anchor your form properly, or you could end up with concrete spreading out instead of forming a nice slab.

Hope this helps, and let us know how it goes!

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Thank you so much! I had no idea that my backyard has so many boulders :slight_smile:

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Our front yard was like that. I installed a vinyl picket fence along the sidewalk a few years ago. It was nice soil on top, but about 10 inches down it was all big rock and stones which had spread out from the base for the sidewalk. There are eight posts, and I had to break all that stone to get the holes down past 24 inches.

The nice part about a breaker bar is that all you have to do is lift it, and then guide it while gravity does the work. It’s an amazing feeling when the rock breaks!

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