Hot take: a magnesium float is not always the right call for a broom finish

I was working a driveway in Tampa last Tuesday, maybe 80 degrees and humid as hell. Wanted a nice broom finish so I figured I'd use my magnesium float to open it up smooth before the broom. Big mistake. That float sealed the surface just enough that when I hit it with the broom, it left these weird drag marks and the aggregate wouldn't push through evenly. Looked like a cat walked across it. Ended up having to run a light rub with a sponge float to blend it all back together before it set too far. Customer was watching from the window the whole time too. Has anyone else run into this issue trying to broom after a mag float?

2 comments

2 Comments

the_nina12d ago

Whoa, I gotta say I used to be on the opposite side of this. I thought a mag float was always the way to go before a broom, just to get it extra smooth. But your experience really makes me reconsider. I can totally see how that sealed layer would cause the broom to skate instead of bite, especially in that humidity when the surface sets up faster than you'd expect. Never thought about the aggregate not pushing through either, that's a good point to keep in mind.

evannelson12d ago

Tampa humidity is a beast, I know it well. That mag float in 80% humidity will trap surface moisture and create that slick skin you described. Next time, try a wood float instead - it leaves enough texture for the broom to grab without sealing the top.