I picked a magnesium float over a steel one for a big garage floor and everyone said I was wrong

We were finishing a 40x60 garage slab in Boise last spring, and the crew was set on using a steel bull float for the first pass. They said it was the only way to get it flat and tight. I argued for a magnesium float instead, because the mix had a lot of pea gravel and I was worried about the steel digging in and leaving tracks in the softer spots. The foreman laughed and said I'd end up with a 'spongy' finish. I stuck to my guns on my section. The magnesium glided over the aggregate without catching, and I could keep working it longer without fear of scarring. When we came back for the final trowel, my area was just as hard and way more uniform to start on. Their sections had a few minor low spots from where the steel had pulled material. I'm not saying steel is bad, but for that specific pour, magnesium was the better tool. Has anyone else had to fight for a different float on a job?

3 comments

3 Comments

danielb432d ago

Yeah, that bit about the steel pulling material and leaving low spots... I heard a guy on a building podcast say that's the exact reason he switched to magnesium for most pours. He said steel can almost act like a squeegee on wetter mixes, pushing the fines and cream around. Makes total sense with pea gravel in the mix. Good call sticking to your guns.

gracet222d ago

Wow, I used to think steel was fine but you're right.

nancy5241d ago

Wait, but doesn't magnesium warp way easier in the heat? I've seen steel floats hold up better on big driveway jobs in full sun.