Why does nobody talk about overworking your concrete with the float
I was finishing a driveway in Boise last Tuesday and the surface started tearing up on me. A guy watching from the sidewalk said, 'You're floating it to death, that's your whole problem.' I had no clue that working the float too long brings the cream up and weakens the top. So how many passes do you all actually do before you call it good?
Boise in July is a rough place to learn that lesson, the sun sucks the water right out of the mix before you even get going. But I'll push back a bit here, a weak top from too much floating is real, yet I've seen way more driveways torn up from guys hopping off the float too early because somebody on the sidewalk spooked them. Cream is just the paste and fines sitting on top, and a couple good passes with a magnesium float will work it back in, it doesn't wreck the slab by itself. The real damage comes when you float a wet mix with too much water in it, then yeah, you're just pushing mush around and the top turns to chalk. So the number of passes matters way less than your mix, your timing, and whether the bleed water is gone before you ever touch it.