Should I be worried about the rebar shifting during the pour?

Rebar drifting during a pour is usually caused by the force of the wet mix pushing the cage into the softer soil side, especially if your trench walls aren't uniform. If that steel ends up too close to the edge of the concrete—less than two or three inches of coverage—you're looking at potential **spalling** later on when moisture hits that metal and it starts to oxidize. Since you're dealing with tree roots and clay, the ground is going to hold moisture differently than the asphalt side, which makes that concrete cover even more vital for long-term stability.

What you should do right now while the mix is still wet is use a piece of scrap lumber or a rake handle to pull those cages back into the center. You don't necessarily need to restart, but you have to ensure that rebar isn't leaning against the dirt wall. Even if it looks slightly crooked from the top, having that **minimum clearance** on all sides of the steel is what prevents the footer from snapping when the soil settles or goes trough a freeze-thaw cycle.

Next time, it helps to drive some vertical pieces of rebar deep into the subgrade and wire your horizontal cage to those stakes. It keeps everythign locked in place so the weight of the truck's discharge doesn't blow your alignment out. Since you're right against an existing asphalt edge, you've basically created a rigid form on one side and a soft form on the other, which always encourages the mix to migrate toward the path of least resistance.

Don't sweat the aesthetics of the wet footer too much as long as the steel is buried deep enough. Once you start stacking those Nu Rock blocks, the weight will be distributed across the center of that footer anyway. Just make sure you've cleared out any loose clay chunks that might have fallen in during the drift, because pockets of dirt trapped inside your concrete will definitely create those weak spots and cracks you're worried about.

I had this exact thing happen with my last retaining wall. The truck's chute was pushing the cage right into the mud. I grabbed some old bricks I had lying around and jammed them between the rebar and the dirt wall as a temporary spacer. It kept the steel from hugging the edge while the concrete set up. If you've got some heavy rocks or chunks of broken concrete nearby, just toss those in to pin the cage back toward the center. It’s not pretty, but it’s better than having your rebar poking out the side next spring.

I'm brand new here and totally obsessed with these DIY projects lately! It's crazy seeing how the rebar behaves during the actual pour. Quick question though—since you’re right up against the asphalt, did you have to worry about the driveway edge crumbling while you were digging? I want to do this next to my garage, but I’m terrified the weight of the truck might crack the existing pavement if I dig too close. Also, do those blocks come in diffrent colors or is it just the standard grey?

Back in the day we didn’t have those fancy blocks, we just poured the whole wall. If your cage is walking on you, you're lucky you didn't have to deal with the old wooden forms blowing out from the pressure. Since you’re digging near roots, you better watch for heaving. I’ve seen clay lift a footer two inches in a bad winter becuase someone didn't dig deep enought past the frost line. Did you throw a layer of gravel down first, or are you pouring straight onto that clay? If that base isn't solid, your rebar centering won't mean a lick when the mud starts shifting under the weight.

You realy need to grab a bag of Aztec Castle Chairs before your next pour. Those scrap bricks or rake handles are okay for a quick fix, but those chairs acutally clip onto the rebar and stay put even when the truck is dumping heavy mix. They’re way better for keeping that steel centered in the trench, especally with that soft clay on one side. I used them on a similar retaining wall project last summer and the cage didn't budge an inch. It’s cheap insurance against that spalling everyone is worried about.

Quick update — I actualy managed to snag some old bricks like one of you suggested to space out the cage before the mix hardened. It definatly helped keep the rebar from hugging the dirt. However, now I'm worried about that point about clay heaving near the roots. Do you think I should add extra drainage behind the blocks to stop the soil from shifting?