Learned the hard way: don't try to power trowel wet concrete in a morning fog

Last week in Nashville I poured a small driveway and figured I'd get a jump on the finish by running the power trowel while there was still a heavy fog hanging around. Big mistake. The moisture from the air mixed with the bleed water and turned the surface into a sticky mess that gummed up the blades and left swirl marks I couldn't get out. Ended up having to grind down the top eighth inch and recoat with a thin overlay just to hide the damage. Took me an extra 4 hours and cost me about $80 in materials I didn't plan on. My buddy who's been doing this 20 years told me he learned the same lesson in Birmingham back in '08. Anyone else run into issues finishing when the humidity is through the roof?

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dylan_thompson2d ago

Ha! Man that's rough but I'm not surprised. One thing I don't see people mention is how fog can basically turn your slab into a salt lick if you used calcium chloride accelerator. That moisture pulls it right to the surface and you get this nasty white crust that ruins your finish before you even start. I've seen guys blame the trowel or the mix when really it was the fog activating leftover accelerator. Might be worth checking if your buddy used any in his mix back in '08. Just something to keep in the back of your head for next time.