Is it normal for the vapor barrier to bunch up this much under the rebar?

Those folds in the vapor barrier are definitely going to be a headache once the pump gets moving. While the weight of the concrete will flatten out some of the smaller ripples, thick bunches or overlaps near your columns are a different story. If the plastic is doubled or tripled up, it creates a void where the concrete can't properly displace the air, leading to a thin spot in your slab depth. More importantly, those high spots in the poly have a nasty habit of floating up into the bottom third of the slab as you're dragging the hose, wich can lead to ghosting or even cracks later on. It is absolutely worth the twenty minutes to cut out the excess and tape it flat before the truck shows up. You don't necessarily have to pull up all the steel; just snip the tie wires in the problematic areas, lift the mesh slightly with a pry bar, and smooth out the yellow jacket. If you have huge folds, slice them open, lay them flat, and hit them with some **seam tape**. You want that barrier as tight as posible so the pump hose doesn't catch a lip and tear a giant hole in your moisture protection.

Since you're working around columns in a tight interior space, make sure you've got some **turtle shells** or even just scrap pieces of plywood to throw under the hose couplings. Dragging a pressurized line over rebar chairs is hard enugh, but if the hose catches a fold in the plastic, it'll bunch it up even worse right where you're trying to pour.

If you're planning on a smooth power trowel finish, those air pockets under the poly can cause weird bleeding patterns or soft spots that won't set up at the same rate as the rest of the floor. It’s a Friday pour and you’re probably tired, but fixing the prep now is way better than chasing a blister or a hollow spot during the finish. Just flatten it out, tape it down, and you’ll have a much more predictable afternoon.

Listen, if you're going to slice those folds like the other guy said, don't just use any cheap tape from the hardware store. It'll peel up the second the mix hits it. I always keep a few rolls of Stego Tape in the truck for exactly this reason. It's the only thing that acutally bonds to that yellow poly when things get messy. Once you flatten those bunches out, slap some Stego Tape over the seams and it won't budge even when the pump hose is dragging across it. Seriously, don't risk the moisture barrier failing becasue of a weak seal.

I’ve seen guys try to 'pour over' those humps since the 70s and it always ends the same way—a spiderweb crack right where the plastic was bunched. Back then, we didn’t even have tape that would stick to wet poly, so we’d just weigh it down with a handful of mix as we went. If those folds are near your columns, check your depth. If you’re only getting two inches of mud over a thick fold, that slab’s gonna snap like a cracker. Take the time now or you’ll be out there with a jackhammer on Monday morning.

I’m super new to this and mostly just lurking to learn, but I keep hearing about this Stego Tape. Is that stuff relly that much better than just regular heavy-duty duct tape? Also, when you guys talk about 'ghosting' from the plastic moving, what does that acutally look like on the surface? I'm trying to visualize how a fold at the bottom shows up on the top once it's dry.

This all sounds so intense! I'm just getting started with my first small driveway project, so reading about 2400 square foot slabs is making my head spin! I'll definitly watch out for those folds now. Speaking of prep, since you're working around all those columns, do any of you guys use those laser levels to check the height of the pour, or is that overkill for an interior slab? I saw a video of one that looked like a lightsaber and now I realy want an excuse to buy one!